Why the high idle?

[Rusnak_322]

OK, got the electrical sorted. Now the idle is high (guessing 3000 rpm, no tach).


Looked over the throttle cable, look like there is slack (new single cable and new throttle on the bar).


Set timing and points.


The carb boots look good, no cracks or other places that I can see leaks.


I rebuilt the carbs last year but I recently reset the floats to 21mm and went up on size on the jet.


before I re-jetted, I didn't have this issue, but I was having problems with the RPMs dropping back down slowly after you blipped the throttle.


I am running stacks and scrambler pipes with emgo mufflers.


What else should I look for? The bike runs good, the acceleration is strong (will get up to 80mph no problem). It recently started to back fire on me through the exhaust.


I bought a HF timing gun, and it doesn't work.


thanks,
Eddie

 

[Rusnak_322]

Not that it should matter, but the bIke is a 1974 Honda CB360

 

[OJ]

I had/have the same issue and after some diagnostics, think I located the issue being the right carb insulator boot. I'm still waiting for new boots so I haven't been able to verify if the new parts will fix the problem.

In my case it is just the right cylinder while left runs ok.

 

[Swapmeet Louie]

from what jet to what jet did you go...?

 

[OJ]

Mailman just dropped off the parts, so I'll test this thing tonight.

 

[djelliott]

How are the carb diaphragms? Also, do the slides move freely?

 

[Rusnak_322]

Mailman just dropped off the parts, so I'll test this thing tonight.

I will have to look. I think that I went from 110 to 112 on the main jet.

The carb diaphragms looked good, but I have not had them opened up since last year when I rebuilt the carbs. When I had the carbs off to do the floats, the slides moved fine.

 

[Sonreir]

Carbs synced up OK? Have you hooked up a vacuum gauge?

 

[OJ]

Ignore whatever I said. The boots weren't the culprit in my case...i.e I have no clue what I'm doing. My idle is still 3000-4000 rpm and can't make it better.