Idle acting funny; weather related issue?

[245luigi]

Recently the like has been acting a little funky after being started after being off for at least 30 minutes. When I go to start the bike one of two things occur:

A) Start the bike, bike idles at ~1800rpm, rev the bike, revs go up come down and hang at 4k and stay
B) Start the bike, bike idles at 4k rpm

Then I go off and ride the bike and the problem seems to fix itself after some time. Idle will return to normal (~1800rpm). Just prior to fixing itself, I can hit the rear break at a stop and the 4k hang will drop back down to proper idle speed.

A couple weeks ago I installed a tach. Prior to that I had been playing with airbox, jets and idle settings for research purposes The newly installed tach indicated I had set my idle 300 rpm lower than stock spec (1850 +/- 100 rpm) So I fixed that and all was well.

Zee Background information:
Stock carb with autochoke
I adjusted the proper idle speed in about 75 F (21 C) weather.
Currently it is about 45 F (4 C) weather.
I never played with the air screw, it is still at its stock setting and is adjustable
I have the stock airbox, 88MJ and Tecnigas exhaust

So in summary, the idle is high (~4k), when riding and stopping idle goes to the 4k, when it gets better (after some time) the rear brake will force the bike to return to correct idle, after a little bit more time the problem goes away. Any ideas??

Side note: The 4k idle is right below when the clutch engages so a very light twist of the throttle and Im on my way! It has made the issue a little bit more fun

[245luigi]

FYI I figured this out. It was because the air screw was too lean. I turned it in 3/8 turn and the bike no longer has a hang! I did a couple mile ride and there were no running issues. I think I may have gone a wee richer than I wanted though because it seems like some lower rpm power (torque?) is gone but I can still hit my max speed. Another day Ill back it out 1/8 turn and see what happens

[Stig / Major Tom]

FYI I figured this out. It was because the air screw was too lean. I turned it in 3/8 turn and the bike no longer has a hang! I did a couple mile ride and there were no running issues. I think I may have gone a wee richer than I wanted though because it seems like some lower rpm power (torque?) is gone but I can still hit my max speed. Another day Ill back it out 1/8 turn and see what happens

Good recovery~!!
(all my vehicles for 30 yrs have been EFI - except for my old Sears lawnmower - and the secret to that seems to be to never change the oil, & never add stabil during the winter and never sharpen the blade....! Sucker runs like a smoking Swiss Watch! I do not miss carbs!)

[naughty lee]

Recently the like has been acting a little funky after being started after being off for at least 30 minutes. When I go to start the bike one of two things occur:

A) Start the bike, bike idles at ~1800rpm, rev the bike, revs go up come down and hang at 4k and stay
B) Start the bike, bike idles at 4k rpm

Then I go off and ride the bike and the problem seems to fix itself after some time. Idle will return to normal (~1800rpm). Just prior to fixing itself, I can hit the rear break at a stop and the 4k hang will drop back down to proper idle speed.

A couple weeks ago I installed a tach. Prior to that I had been playing with airbox, jets and idle settings for research purposes The newly installed tach indicated I had set my idle 300 rpm lower than stock spec (1850 +/- 100 rpm) So I fixed that and all was well.

Zee Background information:
Stock carb with autochoke
I adjusted the proper idle speed in about 75 F (21 C) weather.
Currently it is about 45 F (4 C) weather.
I never played with the air screw, it is still at its stock setting and is adjustable
I have the stock airbox, 88MJ and Tecnigas exhaust

So in summary, the idle is high (~4k), when riding and stopping idle goes to the 4k, when it gets better (after some time) the rear brake will force the bike to return to correct idle, after a little bit more time the problem goes away. Any ideas??

Side note: The 4k idle is right below when the clutch engages so a very light twist of the throttle and Im on my way! It has made the issue a little bit more fun

This sounds normal. The bike has an auto choke which appears to be doing its job correctly. By giving more fuel to a cold engine, you would expect it to tick over higher than when the engine has reached running temperature. Put the air screw back to its original setting I say