Classic Motorcycle Insurance with Bennetts - the UK's top bike insurer.
Get a great deal on your bike insurance from Comparethemarket Bike Insurance to see how much you could save.
Bikesure is the 100% British specialist classic bike insurance broker.
Thinking of upgrading your bike's headlight to HID? Read here for things to consider and save 35% on an HID Kit
Reviews
Set Your Theme: 
The Yamaha TZ series part 1
Every now and then a machine comes along that grabs the racing world by the scruff of its neck, and opens up a whole new range of possibilities for the private racer. Inconceivable in modern times, during the 70s, it was entirely possible to afford and buy a competitive machine from your local dealer and, with a little preparation, be the owner of a machine capable of winning a club race or grand prix alike. This machine was the Yamaha TZ twin, evolving from the air-cooled TD3/TR3, these buzzy two strokes turned out to be competitive, cheap to run and supremely reliable. The basic engineering involved meant the TZ was a doddle to work on too.
The TZ all but dominated the racing the globe over throughout the 70’s and very nearly lifted a few world titles too, keeping many other manufacturers honest as they did so. The crankcases and general layout of the TZ is very similar to those of an RD but that is just about where the bloodline ends. A six-speed close ratio gearbox forms the transmission and this was fed its vicious power via a large dry clutch and straight cut gears for extra energy transfer efficiency. The barrels are a one-piece liquid cooled affair allowing all of the tuning lessons learned during the sixties to be put into good use. The 250 was good for a reliable 50bhp in standard trim while the later versions of the 350 could put out well over 70bhp making them very handy tools to have around.
The TZ story begins for real in 1971 when air-cooled factory twins bikes first appeared with four lugs already mounted on the front down tubes, upon which the radiator could be mounted as and when required. By the end of that year the first prototype water-cooled top end was in existence ready for the start of the 1972 season. These were used to great effect by several favoured riders that season, but none more effectively than Jarno Saarinen, who clinched the 250cc championship that year, and finished a close second in the 350cc class behind Agostini and the MV Agusta.
By the end of 1972 the Yamaha factory was ready to start production of the water-cooled production race machine, the TZ350 A. Based loosely upon the R5 roadster, no doubt to make it eligible for US competition, there was some notable differences, the primary gears provided the drive for the water pump, and the barrels were a one-piece design enabling the transfer ports to be larger than with separate cylinder castings.
Power output for the over-the-counter machine was a unprecedented 65bhp at 9,500 revs and it cost a very reasonable £1200.00. For this price you also got a comprehensive spares kit enabling a whole seasons racing without further expense, providing you stopped on it that is. This package, with no viable alternative, was enough to become the favourite mount for a multitude of riders from club level all the way though to GP’s. Once the power band was mastered the bikes were very easy to ride, the 350 being the more flexible than the 250. Saarinen gave the new water-cooled machine the perfect launch by taking one to the USA, beating the established Superbikes of the time to win the prestigious Daytona 200.
The 250cc version of the TZ followed the bigger machine into the dealer’s showrooms midway through 73 and was once again a great deal for the privateer. Many riders found that working on them was so easy they only had the one machine, choosing to change over the top ends between races, thus competing in both classes with little extra expense but with a potential increase in income should success be had in both races.
For the early TZ, the A/B, the chassis was lighter but virtually identical to the RD save for the necessary lugs etc used mount side stands and suchlike. The steel tubing of the TZ frame was much lighter, but even so the RD chassis made a good conversion into a pukka race machine. The Maxton range of TZ powered racers incorporated many of the road bike cycle parts, forks, discs etc in their TT and GP winning machines.
Yamaha placed great emphasis on their race successes with these RD based machines during the 70’s, but in reality they never did officially win the 250 championship as a factory effort. After the initial flurry following the bikes launch, Saarinen’s title in 72 and the one further privateer title in 73, when Dieter Braun took the overall victory, albeit with most points scored on his air-cooled TD3, the 250, TZ or OW never again clinched the crown. The TZ350 faired little better with one world title, when Jon Ekerold clinched victory with the Bimota framed, TZ powered, Solitude. In between those times only the factory 350cc OW machines ever won a world championship and these were wildly different from the customer version.
The OW 16 and, its smaller capacity sibling the OW17, first seen in 1973, looked exactly like the TZ from a distance, but keen eyed observers soon noticed the fairings were much shorter and higher off the ground; this was because the engine was a fraction of the size of the TZ. The OW racers where largely fabricated out of Magnesium and other lightweight materials so, at 29kgs (60lbs) lighter, they tipped the scales far lighter than any TZ. The crankshaft rotated backwards, enabling huge inlet ports without piston damage and the drive was then delivered to the clutch via a jackshaft taking its drive from the centre of the crank, in a similar way to the TZ500 and 750 fours. Power output was well into the high seventies and this was enough to give the Yamaha factory riders Agostini, and Johnny Cecotto, the title in 1974 and 75 respectively. They missed out on any title hope in 73 due to the untimely death of Jarno Saarinen and the subsequent withdrawal of the Yamaha team for the remainder of the season. The Monoshock frame was first seen on Agostini’s OW factory bikes towards the end of 1974 before becoming available to the public in 1976 with the TZ C model.
Cecotto began his 74 championship season with a TZ, but around the midway point of the year, when it looked like he could take the crown, Yamaha provided him with factory support, and with it came the OW16. That was to be the last world championship for the factory twins, Takazumi Katayama did become champ in 77 but that was achieved largely using the European developed 350 triple, based on one and a half TZ250 engines utilising a shorter stroke via TD2 crankshafts, to achieve the 349cc capacity.
The TZ, although not as successful as our memories would like us to think, was the tool to have for the privateer, as with little or no modification it was good enough to grab the odd race win here and there and score heavily in the overall standings. Many a professional racer relied on the good old TZ to earn his keep, every machine in the top ten of the 350 championship of 1975 was a Yamaha twin, either factory or private, a testimony to the types ability. Everywhere the race spectator looked, whether it was at a club meeting, or international event, the Yamaha twins were prodigious. There was precious little you could do to tune them without seriously affecting the reliability, so riders knew that they stood an equal chance at whatever level of racing they participated.
The Yamaha engine was generally very tolerant of all kinds of abuse and many featured conversions enabling the use of the 350 in the 500 class where, in the absence of other commercially available machines, it was a force amongst the lower rankings during the early and mid seventies. The common mod was the fitting of an eccentric crank pin increasing the stroke by half a millimetre, and with it the capacity to 351cc, enough to let it into the premier GP class.
Very little was done to the TZ over the ten years of continued production, the single most drastic change came in 1976 when, to bring it in line with the 1975 factory bikes, the C was introduced with radical Monocross suspension and the single disc brakes used on both the front and rear wheels. This replaced the twin shock suspension and the massive four leading shoe brake arrangement of the previous models and at £1500 for the 250, was met with great enthusiasm by the racing fraternity. For the first two years of its life the TZ had been modified in such a way by a multitude of specials builders like Harris and Spondon so Yamaha were finally giving the public what it really needed.
Pretty soon every top racer in the UK had a C model, and the outdated drum braked bikes were either converted to a disc set up, using mainly RD parts, or consigned to club level.
The subsequent D and E models were little different from the C only minor internal modifications, like revised port timing, was deemed necessary. For the rider, the most important improvement would have been a new design of forks, the front end pattered under load but nothing much was ever done about by the factory, it being left to the suspension specialists to cure. The next, and final, transformation came about in 1979 when the F model was announced. This was a development of the machine that Kenny Roberts and his team had built in readiness for his assault on the 250 world title in 1978. Once again the Roberts machine bore little resemblance to the commercially available version with its extensive use of machined down components and trick parts.
Roberts had used a trick TZ in a GPs some four years before (Actually the yellow and black bike seen here) when he endured a one off ride at Assen, leading the race by a good margin before stepping off towards the end of the race and rejoining to finish 3rd. That race was also very nearly the end of the Californians GP hopes, Kenny recalls “luckily I remounted to finish third and as stood on the rostrum I just kicked off about the amount of money I had just won for a GP placing, and believe me it was a pitiful amount, I could easily have earned more in the US club racing! So when the man with the microphone came around and stuck it in front me, instead of praising my sponsors, I carried on with the rant about the clowns paying to work in the circus.”
It may well have been true, but it went down like the proverbial lead balloon with the organisers so much so that when Kenny and his team left that day, it was made quite clear, that it would be some time before he would be allowed back into the GP’s. Luckily he did return.
The overall design of the F “Lowboy” layout gave the impression of a shorter wheelbase, when in actual fact it was 5mm longer than the previous models, with the tank sat well into the frame tubes and much effort made to reduce weight. Manoeuvrability was addressed via a sharper head angle and, on paper at least, the bike had the makings of a winner. The F model was well received but it soon became apparent it was little better than the previous E version, the front end still pattered terribly and the headstock tubes cracked. This problem carried over into the G series and became so bad that Yamaha had to replace all of the TZ frames, most of them with English built Harris or Spondon replica items.
The 350 F suffered incredible piston wear, thanks to an increase in inlet port area, while the 250 was a poor performer against the latest Rotax powered machines that were starting to be developed to great effect. Yamaha’s immediate answer was the TZ250G, this featured an increase in bore size giving a capacity of 249cc, and whopping 8mm removed from the rear of the piston skirt, saw the power up by 4bhp.
To calm down the rush of power the power jet carburettors from the 350F were used to boost midrange. By now the price of a new TZ had doubled over the price of the 1976 C model and with little improvement was becoming not such a good proposition. The forks stanchions were made thicker, and were re-valved internally, in an attempt to stop the patter, but in reality this never worked and the bike disappeared almost without trace into a sea of Rotax powered inline twins.
The following year, 1981, and for the quarter litre class anyway, the original TZ story was over. Yamaha had the all-new TZ250 H, complete with a price increase to £4500 but it really was half of the factory OW48 racer, with its power valve exhaust mechanism, separate crankshafts, and pressurised lubrication to the gearbox.
Despite its short life, and the up coming end of world championship status for the capacity, the TZ 350G was a success, and once the chassis problems were sorted perhaps, the best they ever made, continuing to be a favourite mount for many a future star, actually carrying on unchanged into the early eighties with the 350H model. In 1982 the 350cc GP class was dropped forever and with it came the death knell for this little machine at world level. They did live on however with many rolling chassis being robbed for the upcoming Formula two series and a new series, The Promoters 350 class, to be run a national level in the UK keeping the remaining TZ’s operational. The sidecar boys also had a use for the twin cylinder engines using it almost exclusively in the F2 championship until the 600 four-stroke engines caught on and subsequently took over.
Yamaha TZ350A Specifications
Engine - liquid cooled, twin cylinder, two-stroke, piston port
Capacity - 347cc
Bore/stroke - 64 x 54mm
Power - 64bhp @ 9500rpm
Torque - 35ft-lb @ 8200rpm
Carburetion - 34mm Mikuni VM34SC
Transmission - 6-speed dry clutch chain final drive
Frame - steel tube cradle
Suspension - 34mm telescopic forks. Twin shock rear
Brakes - 260mm double twin leading shoe drum. 220mm twin leading shoe drum
Wheels - 3.00 x 18 3.00 x 18
Weight - 115kgs
Top speed - 145mph
Wheelbase - 1331mm
Fuel capacity - 23ltrs
Enjoy this site?
Show your support by liking our Facebook page:
Suzuki RG500 Gamma
In 1984, a Yamaha advert quite boldly stated “ No one has ever built a road machine so close in technical basis to a current GP winner. Quite frankly we do not expect that any one else ever will”.
How wrong they were and just one year later they had good cause to regret that statement as the Suzuki RG500 burst onto the scene. Thankfully Suzuki were brave enough to give us not only the visual image, but also a real taste of GP performance with the Gamma. Endowing the machine with plenty of fire from within its four-pot belly, rather than the somewhat castrated, and over weight effort that Yamaha made with the RD500.
Place the RD500, NS400 and RG500 Gamma side-by-side and you would have three of the top manufacturers attempts at producing a replica of their respective GP racers, however, with all but one of those machines, all you purchased was a mere shadow of the original design. That is not to say the others were rubbish, far from it in fact, but the RG was definitely nearer the mark, and actually far closer to the race machine than you might ever imagine.
The Suzuki is almost an exact replica of the race machine, its roots can be traced directly to the 1983 factory XR45 and the crankcases, barrels and general engine layout are virtually identical to the bikes ridden by Sheene, Mamola, Crosby and the rest of the factory boys.
The bore and stroke is identical in design to the race machine, as indeed are most of the engine components although a shock damper was added to the lay shaft to reduce loads between the cranks and the clutch/ gearbox. Starting the engine is achieved by kick-starter and, unusually for a Japanese machine, as the mechanism does not drive the clutch outer gear, but the input shaft of the gear box, the engine has to be started in neutral rather than simply leaving it in first and holding the clutch in.
The engine breathes through four flat-slide Mikuni VM28SH, mounted like the racer in pairs either side of the engine. When viewed from the side these carburettors are incredibly short, only 36mm, and is key to good power from a disc-valve engine. Just like the real racer the gearbox is a cassette type and can be removed in double quick time giving access to the gear wheels enabling different ratios to be fitted for all of the gears. The factory race bikes of 83/84 could utilise up to six different ratio’s for the first four gears and five for fifth and sixth and this feature was retained for the roadster. The ratios chosen for the roadster gearbox are, apart from the ridiculously high first gear, pretty well matched for high-speed use, although the five locating dogs on each pinion do slow down the selecting mechanism somewhat.
It would be reasonable to assume that, although no race kit was announced or in fact produced by Suzuki at the launch of the Gamma, it was obviously originally designed to accept go faster goodies, thus creating a formidable production class race bike. A theory suggested by Graham Dyson, whose UK based company, Nova designed and built a race gearbox for the RG, was that the Gamma was so close to the RG, the factory correctly assessed that a race kit would detract sales from the real thing by providing a much cheaper yet still competitive alternative.
All this power was managed by the Suzuki Automatic exhaust control (SAEC), which utilised a servo power gate that opened up a chamber in each barrel/ head assembly increasing the volume of the exhaust down pipe. The SAEC valve is controlled by the AEC box, fed by signals from the CDI box, then via a stepper motor and cables to the valves. These rotary valves only actuated below 7500rpm by which time they would be fully opened up. This was Suzuki’s variation on the YPVS exhaust valve, and Honda’s ATAC system. The SAEC gave the Gamma an impressive spread of power with good pull available from 5000revs with things getting really serious at 7000 before shooting completely through the 10,000 redline to a worrying, but non the less fantastically exciting, 12k According to the Suzuki published power curves there is no actual increase in power above 9500rpm, but it certainly does not feel like that when riding the RG.
Exactly like the race machine, the four water-cooled cylinders are arranged in a square above two stepped crankshafts, with the pistons set at 180 degrees to each other so that they fire in opposite pairs, giving perfect mechanical balance. So smooth is the running of the Gamma that, unlike the 50-degree V-four layout of the Yamaha 500LC, no power sapping balance shafts are required to dampen out vibration, saving much weight and space in the process. The RD will lose something like 8bhp just because of the balance shafts.
Power is plentiful and with a little fettling can be improved enormously. Mildly tuned machines have recorded as much as 108bhp and 55ft lbs of torque. A common mod is the fitting of aftermarket pipes and these can, with a little rejetting, instantly transform your machine. The main reason for this is the original manufacturer has to comply to various limiting noise regulations at certain engine revolutions whereas the after market guy doesn’t.
Total weight for the Gamma was a rather portly 154kgs, but this is due to the equipment required to make it road legal, with this removed the weight soon drops to a more competitive 130kgs. Surprisingly in standard form the Gamma is actually 9kgs lighter than the Honda NS400R. The aluminium square section frame, constructed along the same lines as the GSXR 750 but with a much heftier steering head, held everything nicely in place and gave a very precise ride, the massive steering head doubles up as the entrance to the six-litre air box and filter housing.
The handling is very good particularly on a track although the sixteen inch front wheel sometimes makes the RG a little frisky when on the bumpy, pot hole ridden, queens highway. By today’s standards the tyres, 110/90V 16” front and 120/90V 17” rear are skinny but back then this was the very forefront of chassis design. The front forks where the usual telescopic oil damped units with spring pre load adjustment, air valves and the dreaded “anti dive” mechanism, although this one worked reasonably well, located on the front of each fork slider. The rear “Full-floater” suspension system, operated by a rocker arm assembly, was adjustable via a remote knob. For such an agile machine the head angle is a lazy 30deg, with a largish trail of 110mm too. Two 260mm floating discs grabbed by a pair of 4 pot calipers, identical to the GSXR750 of the time, providing the stopping power, with a much smaller rear disc and basic caliper performing the duties at the rear.
In 1986 Padgett’s of Batley began development of a Gamma based TTF1 machine. Having already experimented with the overweight Yamaha, Padgett’s turned their thinking to the Gamma as a potential contender. The F1 rules of the time allowed 1000cc four stroke and 500cc two stroke road based machines, and from the very beginning of development the Padgett’s RG Gamma was competitive, producing power and speed not far off the performance of the real thing. At Hockenheim, that season, the Gamma passed the speed trap at 171mph while the pukka race RG clocked 173mph, a mere 2mph difference.
Lincoln rider, Mark Phillips convincingly won the Shell Oils TT F1 championship in 1986 on the Padgett’s Gamma amongst a sea of FZ750 Yams and GSXR Suzuki’s. Mark remembers “The F1 bike was something very special indeed, actually lighter than the MK10 RG I was racing in the open classes. At Assen, after fitting a race ignition, I had to keep backing off the throttle because it was revving so high I thought it would blow up, of course it never did. In that championship year we only had one mechanical misdemeanour when a gear broke at Mallory and spat me off, after then the problem was sorted and she ran all season”.
A very special Gamma indeed
With out doubt the most famous person to race a 500 Gamma was Kevin Schwantz, already an established star in the US, Schwantz was keen to make a favourable impression with the European GP bosses. Schwantz had already set the UK scene alight earlier that year when he stormed the Transatlantic challenge on a GSXR750 and was poised to make a similar impact on the GP circuit. For TT F1 World round held at Assen, the US rider rode a virtually standard 500 Gamma literally taken out of stock at Suzuki GB and race prepped the week before.
Chief Suzuki race technician at the time, Martyn Ogbourne takes up the story, “No engine modifications were carried out, there simply was not time, just the removal of unnecessary parts, lights etc and the fitting of competition tyres. Assen is deceptively fast with a Donington Park like string of corners, I knew the bike would be out paced in a straight line but relied heavily upon Schwantz and his undoubted riding ability. The gearing required for Assen is identical to both Daytona and the TT with top speeds in excess of 190mph being the norm in the big bike classes.”
The future 500 World Champion finished an impressive second behind Joey Dunlop and his factory V-four Honda. Ogbourne “I had assessed that, with the right jockey on board, the Gamma would lose around three places per lap down the straights but then make up five around the sweeping twisty bits”. Just as amazing is the end to the story, following the Assen race, the RG500 Gamma was returned to standard road going trim, placed back into stock and then sold having had only the one “careful owner” from new.
It is out there somewhere and you could be riding it.
Suzuki RG500 Specifications
Engine - Liquid cooled square-four two-stroke disc valve induction
Capacity - 498cc
Bore/stroke - 56 x 50.6mm
Power - 95bhp @ 9500rpm
Torque - 52.6 ft-lb @ 9000rpm
Carburation - 4 x 28mm Mikuni VM28SH
Transmission - 6-Speed wet clutch chain final drive
Frame - box section aluminium
Suspension - 38mm telescopic forks, hydraulic anti dive. Full floater rear
Brakes - 260mm discs 4-piston calipers. 210mm disc 2-piston caliper
Wheels - 110/90 x 16 120/90 x 17
Weight - 154kgs
Top speed - 133 mph
Wheelbase - 1425mm
Fuel capacity - 22ltrs
Enjoy this site?
Show your support by liking our Facebook page:
Kawasaki H2 750
Mad as a junkyard dog
First of all came the light switch power delivery of the 500cc Kawasaki H1 of 1969, then common sense prevailed and things calmed down considerably. Engines grew in capacity, and became tamer too, but still crazier than the rest of the early 70’s Japanese pack.
Although a basic engine by design, there is something strangely attractive about any multi-cylinder two-stroke. Whether it’s the array of pipes necessary for the engine to function correctly, or simply the noise it makes, kicking a full-blooded stroker into life always turn heads. This is most certainly the case with any of the Kawasaki triples as, at any part in the rev range, the characteristic burble produced is quite unlike anything else. Combined with the resonance of the cylinder fins as they ring in time with the slap of the pistons the sounds is in a class of its own.
The engine is pretty bullet proof too; over engineered crank components keep the bottom end well cared for, while the hefty crankcases hold it all together nicely. Even those big bore pistons pumping up and down the cylinders rarely give any cause for concern as the loads they encounter remain negligible, mainly thanks to the power and torque sitting so low in the rev range. To add to that, the bottom end is well balanced, employing a triangular crank-web design, rather than the usual round section items found on other two-strokes. The H2 is a substantial machine too, matching the size of the three-cylinder engine perfectly to create an aesthetic balance that is still attractive, and modern looking, nearly 40 years on.
The mix of one pipe down one side, and two passing by the other, creates unmistakable look that is uniquely Kawasaki, the only other Jap triple producer of the 70’s opted to split the centre cylinder into two silencers slung below the two outer ones, to give a four pipe look that technically, at least, isn’t supposed to work for a two stroke engine. The Kawasaki, with its correct exhaust set up, does work however and the engine produces power in abundance albeit, in such a manner that makes it among the most manageable of its generation, while being right up there as the fastest too. It’s a great package that, suspect handling apart, adds up to being a really special production motorcycle with a real personality, the like of which we rarely see from the modern bunch of plastic rockets.
Keeping any Kawasaki triple running shouldn’t prove difficult with several, comprehensive, online sites offering advice and help while a burgeoning owners club has all you could ever need in the shape of support to keep your Kwak triple on the road and in great shape. There doesn’t seem to be any shortage of bikes either and many are finding their way over to the UK from the States, many in immaculate condition and with few miles on the clock too, even so prices remain high for as new examples so be prepared to dig deep if a bit of 70’s stroker madness is your desire.
In use the Kawasaki has a number of different personalities from mild mannered street machine to a full on heart pumping Superbike. The combination of high levels of horsepower and torque produce one of the best rides on the planet, unfortunately this isn’t matched by its spindly steel chassis and is always the first to cry enough well in advance of either the rider or the engine. Japanese chassis design was well behind the development work beng carried out in the go department and as such the H2 is among the worst of the 70’s wobblers, especially when pushed or ridden aggressively. It is one of the few machines of the period to feature an effective hydraulic steering damper, and it needed it too. To make matters worse, there is precious little ground clearance to play with, so cornering can be fraught with many fears, be it not being able to hold a tight line as the frame flexes or the pipes dragging along the ground and trying to lift the wheels off. Compounding the chassis woes is the single front brake, it is barely adequate if the H2 is allowed up into the upper reaches of its performance, many owners fitted a second unit to the mounting lugs already on the right hand fork leg and this improves things no end.
It isn’t all bad news, in fact this was the case with most machines of the period and beyond, it is simply how things were back then and in reality a bit like taking a trip back in time. The H2 has a few quirks that adhere to the old ways, neutral being right at the bottom of the gear box being one such thing, requiring the gearbox to pass all the way through the five ratios, before it will sit in a safe position for traffic lights etc.
Keep the revs down around the 5000 mark and the big Kwak will potter around all day, never suggesting it might oil a plug or even produce a cough in disgust of such treatment, let the revs rise a further 1000rpm however and the story changes quite dramatically. The peak torque and horse power occur within 300rpm of each and they produce a massive hit when they sing together, the front wheel becomes lights in the lower gears, easily leaving the ground in the first two, and requiring a good throttle control or risk looping the whole show as the full force of the 74 horses has its way. Once the foibles are factored in, the H2 is a delightful bike that exudes personality. The engine is almost talking to the rider and there is little need to check the tacho dial, such is the surprising spread of power on tap, the five-speed gearbox even makes sense in this package too each ratio being spot on in relation to the next one either up or down while the well set up 30mm Mikuni carbs allow precise metering of the fuel and with it the way the bike behaves when the throttle is opened up. It isn’t hard to see why the H2 was such a hit in its day, there was nothing around, certainly not a standard road bike, to hold a candle to it performance wise while its looks were both sleek and stylish.
Kawasaki H2 Model history
First seen in 1971 the H2 was little more than a scaled up, and mechanically beefed up, version of the already popular 500cc H1 of 1969. The H2 was a child of the 70’s when bigger was viewed as better and among the current crop of dated designs it certainly was. Opting to remain with the air-cooled formula, much weight was saved compared to the similarly designed Suzuki GT750, and the outright performance was high as a direct result. 120mph was a seemingly unattainable figure for a road bike back in the early 70’s and yet the Kawasaki triple could achieve it daily, and without the help of a tail wind, while standing start times were even more impressive. The engine was usable too, the piston port design proved to be tractable and a real pussycat compared to Kawasaki’s earlier attempts with large capacity two strokes. The H2 quickly gained a reputation a serious tool, while its racing counterparts proved to be equally as effective, the basic engine design living on in the staggeringly fast, liquid-cooled, KR750 race machines with Mick Grant being timed at 192mph at the TT in 1977.
By 1975 the pressure from the environmentalist movement had grown and the writing was on the wall for all but the most technologically advanced two-stroke machines, this left the air cooled motors with little future and the H2 was removed from the Kawasaki line up. Kawasaki switched from making high performance two strokes to concentrating on the up coming four-stroke machinery that they excelled at too, although the H2’sreplacement was a relatively dowdy performing four-stroke twin. The type remained a legend however and is now a highly prized machine that can still turn heads among a sea of modern machines.
Kawasaki H2 750 Specifications
Engine - air-cooled, 3-cylinder, piston-port, 2-stroke
Capacity - 748cc
Bore/stroke - 71 x 63mm
Power - 74bhp @ 6800rpm
Torque - 57ft-lb @ 6500rpm
Carburetion - 3 x 30mm Mikuni VM30SC
Transmission - 5-speed wet clutch chain final drive
Frame - steel tube double cradle
Suspension - 36mm telescopic forks. Twin shock rear
Brakes - 275mm disc single-piston floating-caliper, 180mm single-leading-shoe drum
Wheels - 3.25 x 19 400 x 18
Weight - 206kgs
Top speed - 120mph
Wheelbase - 1410mm
Fuel capacity - 17ltrs
H2 Model Timeline
1969 Kawasaki H1 500
The first of the Kawasaki triples, the staggeringly fast H1, was borne, easily the fastest bike around if a little wild.
1971 Kawasaki H2-750 chassis number H2F-00001
Kawasaki goes one better in 1971 when the 750 H2 was launched. Controllable power and huge amounts of torque combine to take the world by storm.
1973 Kawasaki H2-A chassis number H2F-23671
Chrome front mudguard and graphics apart, there was little separating the first model from this later version.
1974 Kawasaki H2-B chassis number H2F-32201
This model saw a number of changes not least a complete redesign bringing the styling in line with the new range of middleweight triples. Numerous engine enhancements were implemented too, along with a lengthened swing arm to keep the front wheel on the ground a little more often.
1975 Kawasaki H2-C chassis number H2F-42547
A new longer tank was introduced for this year while the hydraulic steering damper shifted sides from the right to the left. This marked the end of the line for the big Kwak stroker.
Enjoy this site?
Show your support by liking our Facebook page:
Yamaha FS1E “Fizzie”
Yamaha Fizzie Fifty
In the 70s there was but a few thoughts that occupied a young lads mind, of course girls was the major distraction, as was the dream of being a pop star, but getting on the road as soon as possible must have ranked up there among them. At sixteen the wide world beckoned and the only way to achieve mobility without mum and dads taxi, or a pushbike was to get a ped.
On the 15TH December 1971, transport minister, John Peyton decreed that all 16-year olds should ride only mopeds, the government of the day reckoning the legislation that required a moped to have pedals would mean that the machine would be little less than a bicycle with an engine bolted on, but how very wrong they were. The manufacturers simply added all but useless pedals to their existing ranges and the end result was a breed of nifty fifties that quickly gained cult status, and with it a whole load of bragging rights about the top speed these diminutive machines actually got up to.
The most popular of these machines was, and still is the Yamaha FS1E, even before the paint job became something that King Kenny would be proud to wear, the Fizzie proved to be the best seller by a good margin. One could argue the competition wasn’t strong, the Honda SS50 didn’t perform as well, and the faster and more expensive Italians lacked a consistent presence on the high street, leaving the Yam a clear run into the affections most teenagers. Suzuki had a good stab with their AP50, but it came with a higher price tag and was a shade more fragile under pressure. The early models sported drum brakes all round and, with little weight to haul up, these worked very well, even so the FS1DX model of 1976 appeared with a hydraulic disc brake up front. This mimicked the styling of the larger Yams a treat and was more than enough to keep the Fizzie ahead of its nearest rival, Honda responded, some two years later, by fitting a cable operated disc brake to its slow poke SS50.
In use the Fizzie is a pleasure, the engine is powerful enough to keep up with the traffic, while the chassis is surprisingly taught and sweet for such a humble beast, one can only guess the manufacturers were cashing in on banking way of thinking where people rarely left a bank after opening their first account. Many a Fizzie rider would have returned to the dealer to part chop against an RD twin a year later and with that move stay within the Yamaha camp that little bit longer. The all down, four-speed box is a little strange for those used to the usual one down and the rest up transmission, but it soon becomes second nature with neutral all the way up. In first gear it is important to keep the revs up to save the engine bogging down as the clutch is released, but once on the move the disc valve keeps things smooth and quite torquey too. Everything about the small Yam is a delight with the exception of having to carry a small bottle of 2-stroke oil around with you to add to the petrol as you fill the tank. Later models had the autolube system to simplify this task but the original Fizzie didn’t despite having the castings in the cases to enable the oil pump to be fitted. The pedals are nothing more than complex footrests, a simple loophole around the law that demands their presence, but in reality they are about as much use as a chocolate teapot. They do extend and, once a lever has been moved to engage the chain drive, will administer motion to the rear wheel, but they can never propel the Fizzie at any speed that will make walking a less attractive option.
Yamaha produced well over 200,000 of the original Fizzie, and the type lived on for a good many years after its initial rise to dominance. During the late 70s the Fizzie, like all mopeds, lost its pedals and was castrated too, with its top speed limited to just 30mph, the styling changed considerably in keeping with the rest of the Yam range and those in the know soon realised the parts needed to liberate the extra 15mph were exactly the same as those from the earlier version making it a doddle to derestrict. As the 1980s moved on, automatic scooters grew ever more popular, and the day of the geared fifty was coming to an end, they do still exist but not in any major manufacturers model range making the Fizzie obsolete for all but the 40 something’s who look back lovingly on their time with the breed.
These days, and with so many having started their biking careers on them, the FS1E is a popular restoration but with that comes some hefty price tags for mint examples. Parts are plentiful, although some genuine Yamaha parts are getting rarer and with it pricier, however with the pattern market taking up the slack it enables the FS1E to be used as a reliable day-to-day transport should that be your bent.
Yamaha FS1E Specifications
Engine - Air-Cooled 2-Stroke Single disc valve induction
Capacity - 49cc
Bore/stroke - 40mm X 39.7mm
Power - 4.8 bhp @ 7000rpm
Torque - 3.6ft-lb @ 6500rpm
Carburation - 16mm Mikuni VM16SC
Transmission - 4-speed, wet clutch, chain final drive
Frame - Pressed steel back bone
Suspension - 26mm telescopic forks, Twin shock rear
Brakes - 110mm single leading shoe, 110mm single leading shoe
Wheels - 2.25 x 17 2.50 x 17
Weight - 70kgs
Top speed - 45mph
Wheelbase - 1160mm
Fuel capacity - 6ltrs
Enjoy this site?
Show your support by liking our Facebook page:
Kawasaki KR500
Kawasaki has had a fleeting romance with premier class of GP racing over the last thirty odd years or so, first of all during the early seventies with Dave Simmons and Ginger Malloy on the air-cooled, roadster based triples and then with a full on radical design for a short period during the turn of the eighties before returning in more recent times with a four stroke Moto GP machine. Only the roadster-based racer to date has been ultimately successful with the Malloy chasing Agostini and the MV home for second overall in the 1970 championship and the late Dave Simmond’s winning the 1971 Spanish GP, so far the best result in a 500/Moto GP race by latter day Kawasaki is third place.
That first triples along with the modern day Kawasaki racers were and are quite conventional when compared to the rest of the opposition while the bike in the middle stood no such comparison against any machinery of the day or indeed since. The KR500 featured a monocoque aluminium chassis and a completely new design of engine based upon the same thinking behind the all-conquering square four disc valve RG500 Suzuki. We say all conquering of course but this isn’t strictly true, as “King” Kenny Roberts on the ancient Yamaha inline four had quite convincingly won the 500cc class for the three previous seasons. Although the Yam wasn’t such an advanced design it would appear that the nut holding the handlebars was sufficient to take the title for the tuning fork brand. A very similar thought could be aimed at the KR500 because on paper at least the square four machine is so very nearly there performance wise and the imaginings could well be if only they had sat a top jockey upon it, it may just have won something.
The trouble with those thoughts is it did have several “top jocks” sat firmly upon the lengthy lime green machine including four times 250 and 350 world champion Kork Ballington, antipodean superstar Greg Hansford and future multiple world champ Eddie Lawson, all had a punt around on it and still never got to the very top step of a GP podium. Ballington did make it into the first three at GP level on several occasions, also nabbing the UK domestic 1982 Shell 500 trophy as well as finishing second in the open class against stiff opposition from the Haslam’s and the like of this world.
What’s it like?
Sat in the pit lane warming this twenty three year old machine up before the off amongst a whole host of open megaphone and rasping race bikes, the KR felt very crisp and responsive to throttle inputs. From the moment we took to the track the Kawasaki was “rev happy” and willing to hoist its skirt up and get on with it. Braking into Redgate for the first time felt absolutely spot on and as the session went on this sensation got better and better and is perhaps one of the finest machines ever in this area. The chassis stays flat and stable, never trying to stand on its nose like so many other race bikes of the period, this is directly attributable to the mechanical anti dive that uses the caliper action upon the disc to lock up the front end and prevent it from diving into oblivion. This pays dividends a few yards later on when the gas is applied as the chassis is not out of shape and struggling to rebound, it just sits square as the brakes are let off and the rear refuses to squat into the all too common potential high side.
The result is a confident application of power all the way to max revs quite quickly. Acceleration is brisk and business like with the engine pulling very strongly above the 7 k mark and maintains a good hefty pull to 11 and above. If anything the engine is as good if not slightly better than the opposition certainly once a bit of momentum is gained within the workings although low down it does lack grunt compared to the benchmark RG500 of the time. Several laps into the test and things were starting to get more race like in pace and the KR still behaved impeccably although Coppice corner began to be one long, but predictable, tail slide as the lengthy chassis struggled to keep up with the speed of cornering.
Technically speaking
Chassis wise the 1980/81 spec Kwak, being a true monocoque, construction that sees the tank formed as part of the aluminium chassis, is like few others from the period or since. The thinking behind this is to keep the weight down for a low centre of gravity and the frontal area small for high-speed aerodynamic effectiveness. The bike is so slim and aerodynamically effective that the front mudguard has to be formed into a duct at the rear to force air into the huge radiator.
We now know that a low centre of gravity is not necessarily a good thing for high speed as a bike has to lean further for any given corner speed although the advanced streamlining is a very good idea. Originally the one piece ally frame was attached to the front of the engine via down tubes running from the headstock but early tests proved these to be the cause of a severe vibration so bad that the clip-on’s had to be rubber mounted which in turn gave a squidgey feel to the steering. Kork’s brother Dozy was also the chief mechanic on the project and he elected to run the first bikes with these down tubes loosely attached instead of firmly bolted and that all but cured the vibes. As can be seen here the later variants did away with the tubes altogether.
The suspension is pretty radical too with the mechanical anti dive operating via the brake calipers torque reaction to the discs and the rear “rocker arm” suspensions soft, compliant approach to damping. Almost all of the rear suspension travel can be used up just sitting on the bike but in use this absorbs all of the track bumps and hollows effectively giving a sure footed ride particularly around the recently resurfaced Donington circuit.
Kork’s take on it
We took the opportunity to ask Kork about his experiences with the KR500, catching up with him at his home in Brisbane where he now runs a successful fasteners business.
KB
The bore and stroke was about the only similarity between the KR500 and KR250. I think the emphasis of the factory was stability and strength, we could have hung a V8 in that Chassis! The KR500 was at least 100mm longer than the Yamahas and Suzuki’s of the day so it did feel incredibly stable but was more suited to touring rather than racing. The 3 cylinder Hondas that appeared around ’82 were possibly a bit shorter still than the Yams and Suzys. Their years of experience in GP resulted in wheelbases that were more appropriate for racing. Kawasaki’s inexperience in 500 racing led them to develop a bike around the requirements of their test riders who were doing the bulk of their riding on the bumpy 5.5 km banked oval test track near the town of Yatabe called J.A.R.I. (Japanese Automobile Research Institute). This is why the KR500 is exactly as you describe it. It was very stable on very fast corners and very difficult to change direction on, the approach to Maclean’s a good example.
It was terrible in chicanes and no settings would get it through them effectively. The only solution would have been to shorten and lighten it, which the factory steadfastly refused to do. Unfortunately in GP’s chicanes were becoming prolific and fast corners were disappearing.
I had no problems in that dept. Gregg never complained, however he never did too much racing on it due to injury. Eddie Lawson raced one in the states without success. I would love to get his view. I know they stopped racing the ’82 model because, as written by USA Journalist Dean Adams: “Kawasaki packed up and pulled the KR500 out of the class halfway through the season after Eddie Lawson hurt himself trying to keep up” (with Mamola and Roberts.)
It was awesome on brakes and was the only real area where I was at an advantage against the others.
I think they did develop the bodywork in a tunnel so it was probably as efficient as you could get a 500cc machine.
The ’81 KR500 was never as fast as the Yam or Suzy, particularly accelerating from slower corners, so it was difficult to beat them to the corners in the first place! No traction at the rear once the tyre was hot made it extremely difficult to keep up let alone stay ahead.
If a long wheelbase such as the KR500′s created faster cornering speed then all factories would have made their bikes as long. Shorter, well-balanced GP 500s have just as high a cornering speed. Short wheelbase bikes are less harsh on the rear tyre, grip like crazy and tend to have a more violent breakaway whereas long bikes get to a limit and drift lazily (causing unwanted extra heat in the rear tyre) limiting what you can do but do not have a higher cornering speed than the short bikes. Long bikes might be a bit easier to ride in fast corners but not faster under GP racing conditions. Short bikes achieve the same corner speed with slightly less lean than longer bikes. Hardly a problem when touring but it makes a difference at the limit particularly with rear tyre profiles designed around the short bikes.
I learnt to ride around the bikes faults where possible but the biggest problem we had was one nobody could do anything about and was by far the most frustrating and debilitating thing imaginable. When ridden hard heavy bikes heat up the rear tyre more than light bikes and long bikes heat up the rear tyre more than short bikes. A heavy long bike heats the rear tyre up quickly and effectively to the point where it has no useful grip to be able to race competitively. Pete Ingley (Dunlop’s chief technician) and I proved that the rear tyre was getting way hotter than was considered acceptable by taking the tyre temperatures out on the circuit after laps and comparing them with a shorter bike. Front: reasonable. Rear: too effing hot!
Dunlop had developed their slicks over many years around feedback mainly from the lighter shorter Suzuki. They were not prepared to go to the expense of building a stronger construction slick and experiment with compounds for one very heavy bike so we were stuck with a tyre clearly not suitable.
The rear tyre used to cook within laps and for the rest of the race I would be nursing it home. On a few occasions I finished within metres of podium positions but was unable to challenge because the bike was already sideways everywhere.
If my memory is to be trusted the bike weighed in at around 40lbs more than a works Suzy, Yam or Honda. Although of ally, the monocoque weighed a lot more than a good steel tube or twin spar ally frame. It and a lot of the chassis parts were too robust and It all added up. The mechanical anti-dive was probably a couple of kg more than a hydraulic setup. Original mag cases were substituted for ally ones which weighed more. The ’82 bike came out even heavier!!
One thing I must say is that the motor was always in the ballpark. In 1981 a little short of grunt but by late 1982 with a major ignition upgrade, possibly the most powerful 500 on the circuit. Had Kawasaki gone for a conventional chassis with appropriate weight and geometry it would have done itself proud.
It is really not easy to explain or convince people of the strange, often counter productive way in which they approached the “development” of a GP bike. We often took one small, meaningful step forward in our quest to get the thing competitive only to get shunted 2 huge steps back by some strange decision from far away!
Basically the engineers did not share our opinions therefore did not see things such as the long wheelbase or weight as a big a problem as we did. They had little or no understanding of what was needed to get through chicanes possibly because of lack of experience and meaningful feedback from the test riders. They had no experience of the tyres getting cooked testing in Japan. I am not even sure if it was ever raced there.
Once they had decided to use monocoque construction it was against their policy and character to deviate. That was no real problem because I think it had huge potential. The chassis would have succeeded beyond their wildest dreams if they had made it small and light. In my opinion the chassis designer, Cowboy Hiramatsu, simply would not take heed of what we (Dozy, Stuart Shenton and myself) needed to improve performance.
Case in point: At the end of 1981 Cowboy told me his design for 1982 would only fit a 16 inch front tyre because he wanted the smallest possible frontal area. I was horrified and got him and the Chief tech for Dunlop together to stress that they were not going to develop the 16 inch any further and that 17 inch was the way to go. Amongst a long list of requirements was the fact that the 1982 bike must be able to use 17 and 18 inch front wheels. Was it such a good idea to gain .1 sec on the straight because of a few sq. mm less frontal area then lose .1 sec on every corner on a dodgy front tyre!!
I can only assume that Cowboy’s design was too far-gone to change and have ready in time for the first GP of ’82. There is a good chance that he might not have changed it even if he had the desire and manpower because he had decided that the bike should have the smallest possible frontal area for aerodynamic purposes.
There was no problem with the 1981 spec monocoque except weight and dimensions. My recommendation to them was to shrink the chassis to as near the weight and dimensions of the Suzuki as they could get it. We had it handling very well as you have experienced but to stop cooking the rear tyre and do better lap times consistently it was going to need to be lighter and shorter. The major design change for ’82 came about because the engineers believed the ’81 chassis was too rigid, an opinion I did not share. They redesigned the ’82 chassis to allow some flex!! This deviation from monocoque to an aluminium “spine” style meant the chassis could no longer hold enough fuel so a large heavy tank was added!
1981 Kawasaki KR500 Specification
Engine: water cooled four cylinder two stroke disc valve induction
Bore & Stroke: 54mm x 54mm
Capacity: 494cc
Power: 120 bhp
Carburetion: 4 x 34mm Mikuni round slide
Transmission: six speed, dry clutch
Chassis: aluminium monocoque
Wheels: front 300 x 16” Dymag (18” used sometimes) , rear 400 x 18” Dymag
brakes: front 2 x 290mm discs Kawasaki magnesium twin piston calipers, rear 230mm disc single Kawasaki magnesium twin piston caliper
Suspension: front 38mmm telescopic Kayaba forks, rear; triangulated rocker arm single Kayaba shock
Wheelbase: 1450mm (58 inches) RG500 1360mm OW48 Yam; 1350mm
Weight: 150 kgs ( 330 lbs). RG500 135 kgs (297lbs) OW48. Yam 135kgs (297lbs)
Top Speed: in excess of 180mph depending on gearing
Enjoy this site?
Show your support by liking our Facebook page:
If you have a classic bike review or restoration project worth adding to our database then please email info@classic-motorbikes.net
Categories
- 5TA Speed Twin
- AJS
- Ariel
- Brough Superior
- BSA
- Bultaco
- Coventry Eagle
- DMW
- Douglas
- Ducati
- Francis Barnett
- Gilera
- Greeves
- Hesketh
- Honda
- James
- Kawasaki
- KTM
- Laverda
- Matchless
- Moto Guzzi
- Motorcycle Racing Legends
- Motorcycle Restoration
- Norton
- OK Supreme
- P&M
- Royal Enfield
- Scott
- Sun Motorcycles
- Sunbeam
- Suzuki
- Thunderbird
- Tiger Cub
- Triton
- Triumph
- Velocette
- Vespa
- Yamaha