idle speed problem

[toolinalong]

My bike has recently begun to exhibit an odd behavior. When it gets warmish (not really hot) the idle speed drops to the point (500-600rpm) where it almost stalls, in fact it will stall sometimes if I do not blip the throttle. This happens when the ambient temp is around 70 degrees and I have been driving on the city streets, i.e. stop and go, for ten minutes or so, and then goes away once I am back in the canyon headed home. Also when first started up and when relatively cool from driving the canyon or highway it is fine.

2002, 38k miles. I had the full service at 36k last Septmeber, the problem started after a winter lay-up of 4 months. I have put on about 1200 miles since the snow melted in late March.

Any ideas?

[daslimpet]

Exhaust valves too tight? My Virago exhibited similar behavior once. Started and ran fine until entirely warmed up, at which point the idle would drop and try to stall. I turns out that the valve lash was too smal, and when the engine heated up thermal expansion of metals resulted in valves that never completely closed. The resulting loss of compression was most pronounced at low rpms, so the engine idled poorly and weakly.

That's just one guess...

Could be electrical related: hal sensors are vulnerable to heat, as are coils. I sort of think that the bike would not want to run well at any rpm if those were the culprit.



Any other ideas anyone??

GOOD LUCK, TOOLIN'! Let us know how it turns out!

[owldaddy]

Since the engine was running fine before winter lay up. I would suspect partly clogged injectors. Leaving fuel in a tank that long isn't a good idea. Did you use Staybil before parking it for 4 months? If not, maybe a dose or two of Sea Foam or Techron will fix the problem. It sure can't hurt to add some to the tank anyway, it is cheap and may fix the problem.
Don