idle speed increases with temperature

[nander]

I'm posting this one in "carburation" because I'm hoping it's a carburetor rather than ignition issue.

Here's the problem: On my CB77, between cold startup and warm running, there is 500-1000 rpms difference in idle speed. Currently, I have the idle adjustment set so that the motor runs at about 1200 when hot. This means that at startup, I have to hold the throttle slightly open because it won't idle (wants to be at >500 rpm).

If I set the adjusters to let the bike idle around 800-1000rpm when cold, the motor will be idling near 1800-2000 rpm when hot.

Anyone experience this issue before?

Thanks,
nander

[Wilf]

I wonder if the increase in temperature opens up a slight vacuum leak and leans out the mixture?

Wilf

[LOUD MOUSE]

This is not at all uncommon.
When I first start/ride I find the same thing and I always Start it then after apx. a minute I take off and never a IDLE problem when I stop. ...............lm

I'm posting this one in "carburation" because I'm hoping it's a carburetor rather than ignition issue.

Here's the problem: On my CB77, between cold startup and warm running, there is 500-1000 rpms difference in idle speed. Currently, I have the idle adjustment set so that the motor runs at about 1200 when hot. This means that at startup, I have to hold the throttle slightly open because it won't idle (wants to be at >500 rpm).

If I set the adjusters to let the bike idle around 800-1000rpm when cold, the motor will be idling near 1800-2000 rpm when hot.

Anyone experience this issue before?

Thanks,
nander

[nander]

Thanks LM -- It's good to hear that this is not uncommon.
Wilf -- I had thought it was some small vacuum leak that I would need to chase down.