Yamaha xs650 special idle problems?
When i first start the bike up it idles ok perhaps slightly sluggish but when it has warmed up from riding and i stop at a stop light or stop sign and hold the clutch in it idles really high. if i hold the brake and let out on the clutch a little it will bog the motor down and regulate the idle again. sometimes it wont. then when i turn the bike off there is always a semi loud backfire. does anyone know what the heck is goin on?
Comments
Sounds like the choke is stuck on.
Are you still using the stock exhaust?!? And has the bike been re-jetted for any new additional exhaust?
If the air filter is clean/unblocked than the carbs probably need a thorough cleaning/rebuild and/or the valves need adjustment along with the cam-chain adjuster tightened.
All the proper specs can be found in a Shop Manual for that bike but the bike has to be over 25 years old so good luck.
If your carburetors are clean, diaphragm intact and synchronized, and still having the problem, then it could be cylinder valve leak. Need to grind and seat the valves. Get a compression test.
Your pilot jets are dirty causing what is called 'hanging idle'... pull and clean them (may as well do a full carb clean while your at it) and all will be well again.
Try synchronize the carburetors.
Next check for leaks at carb tops.
The throttle slide diaphragms stretch, ware out, get torn and leak.