Kawasaki H1 Special

Kawasaki H1 Special

Damien the Kawasaki H1 plus 1 – “Not stock and four smoking barrels”

Kawasaki H1At first glance, Roger Ramm’s machine is just another nice 70s bike, albeit well put together and very well maintained. Many will have passed by without giving it a second glance, as it can take some time, and a close inspection, for the brain to register the extra pipe and cylinder. Once the full extent of the work that has been carried out has sunk in, then one can fully be in awe of the end result. Roger, having carried out most of the work himself, was determined to bring the H1 into the twenty first century by adding modern brakes and the extra third of a power plant, without losing the original looks and style.

Having purchased the H1 from new back in July 1973, Roger, then 19, is still the only name on the log book. It was two-tone green back then, and lasted for all of six weeks before a combination of youthful exuberance, and the bonnet of a Morris Marina, saw the potential demise of his pride and joy. Luckily the machine was rebuilt, after much deliberation from the insurance company, ( thankfully the Marina didn’t fair quite so well) and 8 months later, Roger and the H1 were reunited on the road.

Kawasaki H1 SpecialThe broken arm and leg that Roger suffered bouncing off the Marina didn’t dampen his enthusiasm for the triple, and he set about tuning it to further enhance the already staggering performance. Sprinting became an obsession in the mid 70s and the 500 speedily made its way up the quarter for four years, recording a best time of 12.19 seconds, with a terminal speed of 119 mph. During this period many of the stock parts were junked in an attempt to save weight and increase performance. Among these parts were several very hard to find pieces like exhaust pipes, airbox and the grab rail, something Roger was to bitterly regret thirty years on. Roger also used the bike as regular transport during the eighties before laying it up and neglecting it for well over a decade. Two years ago Roger finally found time to take stock and have a look at the 500 as languished in his workshop. “It was in a terrible state” he admits “ after all of the good times it had given me, this was how I had repaid it”.

Kawasaki H1 EngineAround the same time Roger caught sight of the four-cylinder H2 owned by triples club member John Edge, “ that H2 was the best bike I had ever seen” he admitted. “It was simply superb, Allen Millyard and done the work to the engine and I wanted one, immediately I knew what to do with the 500. A quick calculation revealed the resulting capacity to be as near as damn it 666cc and that was it, I was sold on the idea of a four cylinder machine”.

The next step, getting Allen Millyard to take the job on, was the easiest. He just needed reassuring that it wouldn’t end up as a piece of workshop junk and that Roger was capable of tackling the rest of the work required to fit the extended Kwak lump into the frame.

Four weeks later the completed casings and crankshaft were returned to Roger’s workshop for the fun to begin. Thankfully, Allen had provided lengthy notes on what to expect next when it came time to put it all together. Various parts were ordered or sent off to the relevant suppliers, Hagon built the wheels and supplied the rear shocks while drawings were sketched for a new box section swing arm to be fabricated. Four, 32mm Mikuni Flat slide carbs were acquired and the basic jetting guessed at by Allen’s Performance of Nottingham, the price of the carburettor parts alone adding up to shade under the cost of the bike in 1973.

H1 SpecialWith the motor now considerably wider on the left side by around a third, the casings needed squaring up in the frame by moving it several inches to the right. This in turn meant the all important chain alignment would be out by the same amount; Roger fabricated a lengthened output shaft for the gearbox and supported this with an outrigger bearing support attached to the left casing. The result is a perfectly stable piece of engineering that is more than capable of supporting the huge strains seen at this point of departure for the engines power. Further complex engineering work saw roger machine each barrel to allow the fitting of a 1mm spacer to raise the whole porting. During this operation the lathe grabbed one cylinder and threw it across the workshop. Roger feared the worse and that he had lost a valuable and scarce middle pot but thankfully the gouge made by the lathe was shallower than the job he was trying to do so the barrel wasn’t scrap.

Originally the ignition consisted of a four contact breaker set up powering a brace of Suzuki GT380 coils, but this proved trouble some and has since been upgraded. Sparks for the four pots are now provided by a unique custom made Dyna S system, this gives a whopping spark, almost good enough to weld with. Mark Hutton of A & H performance cycles of Ash in Hampshire is the guy responsible for much of the electrickery found within Damian, Roger is quick to praise his high standard of workmanship and proficiency. Lubrication is taken care of by an oil pump taken from an H2, these have four outlets as standard so can provide oil to all of the cylinders without modification. A special throttle cable had to be made, with five cables now leaving the junction box to provide actuation to the four carbs and the oil pump.

H1 KawasakiWith most of the serious stuff taken care of, it was time to start thinking of the aesthetics. A pair of Pretech calipers were made to fit the standard fork legs, complete with the “666” logo machined on the outer faces. The six-pot calipers grab a couple of EBC floating discs originally intended for a Z1. All that was missing to finish the cosmetics side of the bike was a grab rail, the exact part Roger had dispose of so many years previously. The hunt began but to no avail until triple guru Rick Brett of RB spares uncovered one and duly presented it for inclusion in the project. “The way Rick gave me it you would have thought it was a gold bar” laughed Roger, “ A gold bar would have been considerably easier to find” he added. The paint job, also provided by RB spares, is beautifully applied, being based upon the scheme from the early 350cc triple. The end result is an eye pleasing mix of both modern and old.

Gazelle exhausts of Cardigan, Wales, built the lovely looking stainless steel pipes to Roger’s own design. Once again a top job has been carried out, and the result is totally in keeping with the rest of the machine. The silencers are easily detachable enabling the full on, 70’s un-silenced, sound to be recreated should the circumstances permit it. Surprisingly, considering the guesswork involved in the carburation and other set up matters, the completed four cylinder machine struck up first kick following the build. Much work followed the initial euphoria however and Roger claims “tons of jets were consumed getting the jetting correct and once it was running something like, the clutch gave up the ghost”. Once up rated with heavy-duty plates and springs the clutch has not given cause for concern again.

Dance with the devil

Kawasaki H1Although visually exciting, the big differences in the bike are discovered once riding it. The extra weight is immediately noticeable as is the width, although the latter doesn’t ever become a problem when cornering as the casings are still some way from the tarmac, however you do appear to have a lot of metal in front of your shins. This presents itself as a problem only when trying to kick start the extra wide engine. The kick lever is no longer directly under your right foot and requires more of a sideways push from your legs, rather than a much easier vertical shove. Thankfully, it does fire first time, and the lever can be folded away out of harms way. The engine is responsive and very smooth, a testament, if one were needed, of Mr Millyard’s expertise at welding engines together, as well as Roger’s mechanical abilities.

The clutch is a heavy thing to get the hang of, thankfully, once on the move, you don’t need to trouble it too much. Not quite as cumbersome is the throttle, it does require slightly more effort to twist the grip but, it does have four carb slides to lift, instead of the three found on the original version. Open the taps, and the engine is most unlike a Kwak triple, the crank has been re phased to create a ninety-degree firing order. This despatches four separate bangs to the rear wheel with every revolution of the engine, making for a staggering power delivery from way down low in the rev range. Producing 74 bhp at 9800 rpm, the total power is up by nearly half from the standard H1 figure, this is largely attributable to Roger’s porting and pipe design with a great ride being the result. The 666 Kawasaki goes as well as, if not better than, it looks.

H1 Special KawasakiEqually impressive is the chassis’s ability to keep it all in check. With Kawasaki triples never among the worlds greatest handling machines, the potential for bad handling would have been immense what with the gains in weight and power. This H1has been effectively tamed, chiefly by the substantial swing arm, and now tows the line obediently. A Kawasaki steering damper also chips in with a bit of extra stability for the front end, this was always bad enough with three pistons pushing it along, just imagine what the front tyre would be doing now with four of them kicking in where it not for the damper.

Just looking at the pictures will tell you how good the front brakes are, you don’t bolt equipment like that onto a bike without superb results. The Kawasaki master cylinder gives a good feel while the six-pot calipers react to any movement at the lever, dissipating the energy built up by the engine effectively and swiftly. Roger has chosen to leave the rear wheel as Kawasaki meant it to be, the drum stopper matches the front anchors well, and further modification is just not necessary.

Kawasaki H1The cackle that the four pipes produce is sweet enough at low speed and positively addictive once the power band is reached, developing nicely into a raucous cacophony as the bike rapidly disappears in a cloud of blue haze. Surprisingly, just pottering about is a doddle too, despite the bikes pretension of the opposite. Riding behind the camera car at reasonable speeds, often a major problem for early piston-ported two strokes, proved to be no such challenge for the engine. It cruised along nicely, always willing to go should the signal be sent down those four throttle cables to the asthmatic Mikuni flat slides. The open carbs do cause a small cough as the Kwak clears it throat, but that just gives you a little time to get ready for the off. The 666 Kwak is as easy to ride as a two stroke ever could be with a strong pulling engine and hardly a sign of a power band to battle with. Of course it does have a step up but the transition onto this is a smooth as a modern machine and not at all like a stroker.

Looking around the bike reveals that all concerned with the creation of the beast know their collective stuff, in particular Roger, who has dreamt up the concept and made a large proportion of the components. The end result being a very professional looking and factory finished machine.

666 Kawasaki Specifications

  • Engine – 4 cyl two stroke piston ported
  • Capacity – 665.3cc
  • Bore/stroke – 60 x 58.8mm
  • Power – 74bhp @ 9800 rpm
  • Torque – 40ft-lb @ 7500rpm
  • Carburetion – 34mm Mikuni Flatslides
  • Transmission – 5-Speed wet clutch chain final drive
  • Frame – Kawasaki steel twin loop
  • Suspension – 36mm telescopic forks, twin shock rear
  • Brakes – 296mm discs six piston calipers, 180mm single leading shoe drum
  • Wheels – 100/90 x 19, 120/80 x 18
  • Weight – 174kgs
  • Top speed – 115mph
  • Wheelbase – 1400mm
  • Fuel capacity – 16lts

Kawasaki H1 Gallery

[dmalbum path=”/wp-content/uploads/dm-albums/H1 Special/”/]