Not many. Not even that many in the UK. They were only imported here and in the USA for a limited amount of years. Very very popular in Continental Europe. The French really seem to dig them. Main problem was that Yamaha priced them at almost FZR/ThunderAce/R1 prices but they only make about 80 ponies at the rear wheel (torqey tho').
Your local Yammy dealer should be able to get parts (consumables and things like calipers are the same as many other yams) no problems.
Engines last forever unless stupid people don't read the manual and adjust the oil level when the engine is cold (not a good idea as they're dry sump engines). Grunty and can rev with the 5 valve FZR style head. Get almost 60mpg (dunno what the hell that is in Km/l). Running costs were cheaper than my GPX600 and servicing is low. Cruises all day at 145Km/h and max out at 225km/h. Most comfortable bike I've ridden. Most comfortable pillion according to missus. WHY THE HELL DIDN'T I IMPORT MINE.
Certainly much nicer on the gravel than any sportsbike but not up to serious mud plugging. Crazy people fit them with spoked wheels/dual sports tyres and go mud-plugging or cross deserts.
Mk1 model up to 1996. 180 deg crank I think. $hit 5 speed gearbox.
Mk2 model up to 2001(i think). 360 deg crack. Detuned TRX motor. Much better lights. More slipper bodywork with better wind protection. Slightly less $hit 5 speed transmition
Mk3 model. 900cc engine. Fuel injection. Aluminium frame. Lighter. R1 brakes. Good 6 speed trans.
Mk4 model. Rumour is Yamaha are bringing out a 1 litre version.
Try www.carpe-tdm.net
Bookmarks