Hi All,

My bike seems to be running great when its moving.  Acceleration is good I only get the occasional puff when shifting from a high rev to the next gear and a tiny bit on shut off.  I have a raptor petcock.

Lately the idle does not seem to want to hold steady.    I have a tach on my bike and when i come to a stop it will go down to 1500rpm(that is what I have it set at with the bike warmed up) but then it will slowly start to fall.  She will get down to about 900 rpm within 20 to 30 seconds.  That is about the time i give her some gas to keep her from dieing.  Oddly I do not seem to have any problems when I am warming her up in the morning.  Any ideas?

So why is your rpm so high at warm idle?

one symptom may lead to the other.

When the weather is warm(as it has been lately) I do not need the choke, but I do on cooler days.  I have adjusted the Fuel/air screw to no avail. I think I have a smaller jet around here somewhere and will try it if all else fails.


I have the idle set high to compensate for this issue.  I had it set at 1200 but ran the risk of stalling out when I clutch in on a rapid deceleration.  I should also mention that this issue is not consistent.  Some days it idles fine, other days it is really bad.  I have not found anything consistent with the weather on when it works or not.

I don't think my exhaust is blocked, but It may be time for a valve adjustment.  

verslagen1 wrote on 07/22/10 at 17:59:30:


Ya it's possible the idle mixture is on the lean side, but I am guessing it's rich, because the problem does not occur until the engine warms up.  I just had a "wandering idle" problem on another bike, that improved when I rejetted the pilot.. actually leaner than stock.

You sound like you are ballpark with your jetting,... idle change may just be because of the heat... Mine does that some when it's hot...
If you don't think it's that,.. I'd look at the slide, to see if it's sticking.... or the decel valve...

When I fire it up & ride off, Im on 1/2 choke, no matter how warm the weather. The idle is low, so I reach down & tweak it up a bit. After the choke is off, ( about 5 minutes down the road), it needs a bit more idle adjust, up a tad. As I ride & it warms up, the idle starts coming up, so I adjust it as I ride, a tweak here, a tweak there. By the time Ive been on the road 20 or 30 minutes, its at full opersting temp & its all settled in. This doesnt bother me at all. I just figure its part of the ride on this bike.

I leaned it out a 1/4 turn on the fuel/air screw and in order to shut up a friend of mine I put some Marvel mystery oil in the tank(talking to him you would think that stuff cures AIDS).  I have the idle set at about 1300 rpm now and it seems to be holding a better.  That said, the temperature dropped in Portland.  I think it is heat related.  in the cool mornings it seems to ride perfectly.  At the end of the day, when its hot, I am still getting some awkwardness in the idle.  We'll see what happens when it warms up again.