The Wheel-Stand King – History of the Yamaha XT500

In Blog, Dual-Sport, Japan by Cas VanderwoudeLeave a Comment

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Preface
To me, the Yamaha XT500 is like the archetypal farmer’s daughter: Strong, slender, capable of doing just about anything, and likes to let her hair down when the work is done. Some of my fondest memories of motorcycle riding when I was younger were of my 1978 Yamaha XT500. I purchased it because my 25 mile trip to work included about 10 miles of rough track and my Suzuki GS1000S was not the best off-road. It was a purchase of necessity. To this day, I can not understand my enduring love of this machine – I was into speed and the XT was no race bike…

Early history
The XT500 was first released in 1976, the very middle of the most exciting decade of motorcycle design and it was only Yamaha’s second attempt at a four stroke motorcycle. Yamaha was languishing at the very bottom of the Japanese “big four” in terms of reputation. Honda had the CB750, Kawasaki the KZ900, Suzuki, the GT750 Water Buffalo and Yamaha, the rather pretty, but underpowered, XS650 (basically a Brit twin copy). The competition between manufacturers in Europe, USA and Japan was very much centered on the big displacement superbike. The off-road market had been somewhat forgotten, except for a few token two strokes from Europe and Japan…

The author's current ride - a 1981 model.  Photo by Cas Vanderwoude.

The author’s current ride – a 1981 model. Photo by Cas Vanderwoude.

Then along came the XT. Designed by Shiro Nakamura, in response to market research that suggested American ranchers and off-road enthusiasts were looking for a reliable replacement for the English scramblers they used to buy (BSA had filled this role but had gone out of business). At first, Shiro was going to go all high-tech on the engine’s ass (oil cooled and DOHC), but after some thought, built a Japanese version of the classic British 500 single. There were differences – this one was going to be reliable, light, oil tight, easy to work on and pretty much bullet proof. The design team’s motto was “A yen for every gram” in an effort to make the lightest possible design. I don’t know for sure but I believe the target weight (much like a weigh-in for a boxer) was 300 pounds. This means there are a lot of aluminum parts that might normally have been steel (the gas tank is one example) and the bottom engine cases were actually magnesium. It did retain a manual decompression though, and starting this bike has thrown many a rider over the handlebars before they discovered the purpose of that little lever. The model was imported to the US until 1981, going through 3 minor iterations (C and D; E and F, G and H versions). These three model series had different frames which means seats and tanks were not interchangeable. They were exported to Europe until the late 1980’s.

The author's current ride - a 1981 model.  Photo by Cas Vanderwoude.

The author’s current ride – a 1981 model. Photo by Cas Vanderwoude.

The Yamaha sales department did not think it would sell very many units – and how wrong could they have been! After the TT500 dedicated off-road version received 5 of the 6 podium places in the first 2 Paris-Dakar rallies (1979 and 1980), XTs sold like hotcakes. They became the standard all-purpose motorcycle on every US ranch, Aussie station, and South African boerderij. Why? – it was easy to maintain as long as you fed her clean gas, air and oil. Electrics were very simple, major exterior bearings could be repacked through grease nipples, and, well, these things just kept on going. If you live on a ranch that’s 2-6 hours drive from a shop, it was exactly what you needed. Why they sold so well in Europe has me baffled. Maybe it was the macho image of riding to the coffee shop on an enduro instead of a Vespa. Yamaha added a dedicated off-road version, the TT500 and a road bike that resembled a British single – the SR500. All possessed essentially the same engine. The engine design stayed pretty much the same and is still in production today as a 400CC road motorcycle for the Asian market (and recently re-released in the US with fuel injection).

This bike seemed happiest on one wheel. With the blip of the throttle you found yourself staring at the sky. Minimal effort is needed to master a wheel-stand on this bike, in fact I was able to run around on one wheel for pretty much any distance I desired. Even my current rider, which has been seriously geared for street use, pops her front wheel with the smallest throttle blip. It was also the bike I learned to do my own maintenance. Armed with very basic tools, A Haynes manual and a shed with a dirt floor, I could do pretty much anything needed to keep the old thumper running.

1979 model restored by the author.  Photo by Cas Vanderwoude.

1979 model restored by the author. Photo by Cas Vanderwoude.

Back in the day, younger riders, like myself, discovered it was an excellent (and cheaper) replacement platform for the classic British Cafe racer. We preferred the XT over the SR because they were lighter and had a stronger frame. Not a lot of effort was needed to transform this dual-purpose scrambler into a neat, light, sleek cafe bike. Being Japanese, it was easy to find parts from other motorcycles that could be customized and the result was a wonderful array of custom racing bikes. Not especially fast, but easily as quick as its British competition. The Yamaha XT500 has a huge cult following in Europe, South Africa and Australia – both as a dual-purpose motorcycle and a platform for a 500cc racing motorcycle. God bless Shiro Nakamura.

1980 model restored by the author.  Photo by Cas Vanderwoude.

1980 model restored by the author. Photo by Cas Vanderwoude.

The engine had two small design flaws – oil feed to the rockers leaves the exhaust side under-lubricated. I think, in order to save weight, the designers kept the oil line as short as possible, connecting it near the inlet valve. The oil then needed to go through an intricate network of little lines cast into the head before finally reaching the exhaust lifter. There is an after-market oil-line that feeds both rocker shafts simultaneously and saves having to rebuild the head every 10,000 miles or so. The other flaw was discovered by people who took the bike to its limits. If (actually, when) the chain broke, the remaining chain would propel itself towards the engine and shatter the bottom engine case. This was an expensive if not terminal end to a day’s riding. An aftermarket guide made from pressed aluminum prevents the damage and is a very good investment.

Maintenance tips
• These old thumpers run hot. Change the oil regularly – every 1000 miles. I use Mobil 1 20/50 V-Twin synthetic.
• Although the engine is a dry-sump type, a small amount of oil stays in the engine sump (about ½ pint). When changing the oil, be sure to drain this and clean the screen filters. There are 3 – one in the sump and 2 more in the line between to oil tank and the engine. There is one at the bottom of the down-tube and often the nut that holds it there is impossible to loosen. I shove a long screw driver up there to puncture the screen to make sure oil is not blocked.
• You will need to become adept at adjusting the valve gaps – they seem to move around a lot.
• Get a grease gun and use it – especially on the swing arm
• Starting problems are often caused by the carb. A rebuild kit is cheap. Take it apart and replace the jets, needles etc and give it a good cleaning.
• Each individual bike seems to have its own starting ritual. However, the one thing to remember is to NOT give her any throttle until she’s ticking over happily. It’s very easy to “snuff out” the engine just after starting. Hot starting can also be problematic. Newer models had a “hot start” button on the throttle assembly at the carb. Use it.
• When looking to buy replacement tanks and seats, do not forget that different years may not be interchangeable.
• It’s common for older machines to “wet sump”. Oil drains past the check valve into the sump. Subsequent starting will result in massive clouds of smoke until the scavenging pump gets the excess oil back to the tank. Replacement check valves are cheap. When you install them, be very careful about the engine gasket. Many of the aftermarket ones are too thick. These let oil past the check valve and you will be back at square 1 (I cut my own gaskets). While I’m there, some bikes I’ve restored have a casting fault at the check valve that limits the flow of oil. It’s easy to spot and file away the excess casting.

Buying guide
The XT500 and its road-going sister the SR500 have a huge cult following but are still readily available for restoration or rebuilding into a custom motorcycle. Price estimate: Expect to pay $1000-2,500 for an unrestored running example, $4,500-6,000 for a good restoration and up to $8,000 for a custom build. The 1976 model is especially sought after due to its relative rarity especially if it has the original exhaust system. The 1980-81 models have electronic ignition which I like. However, the stator has a poor reputation and replacements are hard to find and expensive. Spares and aftermarket parts are readily available.

Lossa Engineering custom build of a Yamaha SR500.

Lossa Engineering custom build of a Yamaha SR500.

If you have one and don’t want it, drop me a line. I’d be happy to take it off your hands.

Resources
Stuff to keep her running
The Vintage Spoke
Thumper Talk
Parts Fiche

Performance and after-market parts
Rex’s Speed Shop
Motolanna
KEDO

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