Thumping good fun
The 70s was a time of great technical advancement within the Japanese sector that left the rest of the world struggling to keep up. Yamaha turned the clock back a few years with one particular model however and, in doing so, started something really big.
There is something unique about the Yamaha XT500. Being a really basic and understated machine, in a sea of late 70s technically advanced and ground breaking machinery, it successfully captured a new audience with its stomping ability while also catching the eye of the old Brit iron brigade. It lacked social graces like an electric start, making it a real riders machine and created a whole new generation of multi tasking two-wheelers, a genre that lives on strongly, many years on. Now every manufacturer has a large capacity all rounder in its line up and, in more recent times, the class of Adventure Tourer has been created to accommodate the more complex of these machines, all tracing their roots back to the original XT500 concept and its many developments over the last 30 years. It also, arguably, spawned a series of simple roadsters, the Yamaha SR500 being little more than a tarmac focused XT, and a style much copied since its introduction during 1978.
The big single, once started, is a delight to be on although off road, it isn’t as sure footed as on the road and at speed across anything other than smooth terrain you do feel as if you are taking a back seat in the control department, the big lump of a bike does handle the bumps and jumps well, it is just that you have little say in how or where it goes afterwards.
Ground clearance too, off road of course, is a major problem with the tall engine sat low in the steel single down tube cradle frame so as not to make the bike too top heavy. This is helped greatly by having the engine oil stored in the frame down tubes reducing the need for a dirty great sump but still the big bottom end gets in the way should you find some low speed lofty bumps. Thankfully, on the 1977 specification machine onwards, the team at Yamaha chose to fit a thick aluminium bash plate that saves all but the heaviest encounters with terra firma. Not surprisingly the XT in standard trim is more at home on the roads and dirt lanes, rather than any serious off road stuff, a terrain best left to the swarm of two strokes from the period, with their more favourable power-to-weight ratios. On the dirt it does adopt a rather bullish attitude, and it is this pig headedness that sees it through obstacles that would stop the two-stroke trailies dead in their tracks. The XT bounces off big rocks, and rushes up steep inclines in a rather ungraceful manner but, you tend to emerge unscathed, yet rather out of control looking, on the other side of such obstacles.
On the move the XT500 is a very well balanced bike lending itself to some silly corner speeds, particularly on trail tires and is a great machine for getting about on. Thanks to nice little weight saving touches like motocross specification forks and suspension the bike is a real sweet performer. Adding to this sugary ride is that thumping big single engine feels far more powerful than the mere 32bhp it puts out, as does the midrange torque which, at 29 ft lbs isn’t excessive but the riding position makes it feel double that. By the time those horses produced at the crank get to the rear wheel they have dissipated to around 28 at the rear wheel but the combination of spot on carburetion and cam shaft timing combine to produce a flat torque curve between 3000 and 6500 rpm making the most of the power at hand. This makes the XT500 a doddle to ride, and the need to be in the correct gear for the speed you are going, becomes of no particular consequence, providing you pull away in the first two, you would never notice which ratio you were in at any time. It doesn’t make a jot of difference if you rev it to pull away or simply dump the clutch at tick over, the mighty Yam will just get on with covering your ham fisted approach and probably pull a minger of a wheelie for you as well. Carburetion wise, and typically Yamaha, the set up is so good that no matter what rev range you decide to open the taps, the engine subserviently pulls away. In later models, this is aided by the accelerator pump, but to be fair, the very first, none pump assisted, version was equally as good in this department.
Tipping the scales at all of 149kgs dry the 500 isn’t a lardy machine by usual standards and this shows when being punted around the road but once the tarmac has been left behind that weight becomes more noticeable and certainly a liability when pitched against other trail bikes. At times on the dirt the XT’s torque and the fast way it picks up power from way down in the rev range does over power the closely treaded trail type rubber and would probably benefit from a more aggressive MX tyre certainly on the rear but then the superb manners its displays on the tarmac would be lost forever and this would be a shame.
The selection of the gear ratios in the five speed box is also a work of genius, if you rev the engine to peak power around 6200rpm and then change gear the engine revs after that shift are, as if by magic, bang on peak torque at 5300rpm, absolutely spot on stuff and evidence of the thought and work that went into designing the big single.
XT500 Model history
In 1975, Yamaha responded to a request by Yamaha America for a big powerful trailie and, as such, originally intended the XT solely for the US leisure market. The idea behind the concept was to combine the very best features of the sorely missed classic British single, with its slightly over square engine configuration, with an all terrain, enduro like capability, a pastime that was becoming a very popular Stateside. At first the Japanese designers were reluctant to turn the clock back with such a project, Shiro Nakamura was the man responsible for the XT power plant and later went on to create all of the Yamaha four strokes of the 70s and 80s. At first he tested several hitech options including oil cooling and a DOHC head, but in the end reverted to a basic and simple design. The US got the XT during 1975 but once released to the rest of the globe during the summer of 76, it was the Europeans that really caught onto the appeal of the single cylinder design.
Yamaha made significant changes to the XT500 throughout its life, the very first specification XT500 came with a rather obtrusive exhaust down pipe that ran the same course as the frame down tube, all the way around to the swing arm pivot, before threading through the frame and exiting just below the right hand rear indicator. This low-slung exhaust became a nuisance every time the bike lay on its right side, no matter what the speed, as the total weight of the machine then lay on this hot and fragile piece of tubular steel, eventually flattening it. What the XT500 did get bang on from the onset was the design of the engine with all shafts and spindles spinning on ball bearings instead of plain metal ones, this was another smart move by Yamaha who realised that this type of design required considerably less oil pressure to lubricate the bearings, and was also cheaper to manufacture and repair. One other clever feature was the use of the frame tubes to hold the engine oil, saving a good few inches in engine height due to the lack of a sump.
Yamaha XT500 Specifications
Engine – 4-stroke single-cylinder air-cooled SOHC
Capacity – 499cc
Bore/stroke – 87 x 84mm
Power – 32bhp @ 6500rpm
Torque – 29ft-lb @ 5400rpm
Carburetion – 32mm Mikuni
Transmission – 5-speed wet-clutch chain-final-drive
Frame – Steel single down tube
Suspension – 36mm telescopic forks, hydraulic/pressurised nitrogen rear shocks
Brakes – 160mm single leading shoe, 150mm single leading shoe
Wheels – 3.25 x 21 4.00 x 18
Weight – 149kgs
Top speed – 84mph
Wheelbase – 1415mm
Fuel capacity – 8.8ltrs
Yamaha XT500 Timeline
1976
The first XT500, the 1E6 model appeared. Easily recognisable by its low slung exhaust, later that year the European spec 1N5 model also appeared, identical in many ways the biggest difference being the lack of spark catching silencer.
1977
A total revamp saw the introduction of the 1U6 model; it retained the look of the original XT. A new high-rise exhaust system kept the pipe work out or harms way while the sump was hidden behind a hefty alloy bash plate.
1978
Beefier fork yokes held the front end in place, while a longer chain guard stopped the chain oil flying all over the pace at speed.
1979
Larger engine fins aided cooling, as did vents in the rear portion of the front mudguard.
1980
Extensive work to the steering head and front forks saw the road handling improve and the front wheel spindle moved to its new place on the front of the fork legs. The XT goes all posh too with a polished alloy tank and gold anodised wheel rims.
1981
Cosmetics apart, this model was identical to the previous years version, the following year its successor, the XT550, made it appearance followed by a whole succession of ever larger capacity trailies. The XT500 would remain in the Yamaha line up, and in its original form too, for the next five years until the 12-volt equipped XT500 was introduced. This model was still around in 1990, some 14 years after the first XT.
Yamaha XT500 Gallery
[dmalbum path=”/wp-content/uploads/dm-albums/XT500/”/]
