Hey all...about 200 miles after buying my bike I noticed the reason it was so hard to start was because the left cylinder wasn't even firing until about 5000 RPM.  Yes...I'm that new to motorcycles that it took me that long to figure it out.  Anyway...I took the bike to a shop and he cleaned both carbs, and put in larger jets.  I forgot what size.  Now the bike starts and warms in less than a minute (yippie) but cold idles about 1000 RPM.  After a little riding the idle comes up to 12-1400 RPM and all is good.  Then after warming up more the RPMs start to hang.  Its throttle response is great going from idle to 9000 RPM, but coming back down is very slow usually hanging around 3000.  At this point I usually let out the clutch a bit to pull the RPMs down, at which point idle sits about 15-1600 RPM.
    I know that running lean can cause the RPM to come down slow, but because of the high idle when warm this does seem to be the problem.  What else could be wrong?  Could this be related to the fact that one cyclinder is now firing after who knows how long and the buildup is burning out of it?  Should I just try to adjust the idle?  Should I take it back and tell the mechanic to look at it?  I'm dumb with this stuff...please help me.

Thanx,
Doug Kelly

mine used to do that after a long, sustained high RPM ride, like 170 miles at 6000-7500 RPM. exact same scenario. I turned the idle down so that it idled around 1200 when it was HOT hot, and it stopped. of course, it made my warm-up time go up, A LOT, but the bike is more responsive and just sounds better when i pull up to a light and my bike isn't taking it's time to go to idle.

Wow. sanityfree giving advice. What's the world coming to?!

I'll give that a try...though playing with the mixture knob is what got me into trouble the last time when I thought I was fixing the problem.  I'll post how it turns out.

Okay...so I've tried adjusting the idle screw and nothing.  Yesterday after a 10 minute ride I was the RPM were up to 1500 again.  I blip the throttle and get an immediate respond up to 4-5K RPM, then I count 15 seconds before returning to idle.  I turn the idle screw down to get the idle settled around 1200.  Now I blip the throttle and get another immediate response to 4-5K RPM, and again 10-15 seconds to return to idle.

 I've read that a vacuum leak can lead to return to idle problems.  How does one check that?  Is that just the WD-40 on the carb seals thing...or is there more to it?

Thanks for any assistance...

-Doug Kelly