I have an issue with the '81 Yamaha. According to "Haynes" she should idle at about 1200. Start her up and she will run just under that for a while then chug..chug.. stall. Fair enough, zip her up the road a bit and she will idle at 1200 for ever. Ride a bit and suddenly she won't drop under 3000, I thought it may be related to engine temperature but for no apparent reason all of a sudden she will idle at 1200 again. :dunno:
The bike sounds good and at 10K purrs like a kitten, well almost! This happens regularly but in no set pattern. :x :o
My best guesse is sticking float or somesuch, I am not madly keen on stripping down the carbs, far too many small and fiddly parts for my liking. Anyone have any ideas as to probable cause? If it is floats is there any way of cleaning by addatives rather than stripping. "Redex" added to last fill seems to have made a small improvement. Is there anything to be gained by draining the carbs to see if there is any visible gunk in there? :?
Cal,
Maybe a sticky slide in the carbs? Did you check the throttle cable and make sure it's not binding in any way. For example, mine used to bind when I had the bars turned too far to the right and it would idle away at 3k till i straightened the bars.
cheers
Jake
Jake, I'm pretty sure it's not the cable, I tried to "wind" it down and it seems all the way. I noticed it at 1200 and 3000 sitting at lights, bars straight but I'll double check by messing about with bar positions. Unlike the GS it is a single throttle cable.