Engine revs high once clutch is pulled in then slowly idles lower until it dies

Jaycee604

Active Member
Joined
Dec 7, 2021
Messages
190
So i have made several of these bikes. But this problem is getting anoyying with this build. After i pull in the clutch while coasting or getting ready to stop (obvs while engine is on) it revs half throttle (sounds high) then Slowly relaxes until it eventully dies. I adjust the idle screw and know how to use it. This does nothing, the carb needle is tuned to rich like all my bikes, only upgrade on this on is high performance cdi and some port work on the jug. Could this be an air leak near intake? It also takes slightly longer to start then my other bikes. Let me know what you guys think
 

DAMIEN1307

Moderator
Staff member
Joined
Jul 23, 2020
Messages
5,202
Could this be an air leak near intake?
More than likely...I use a "viton" O ring in the carby where the intake tube slides into the throttle body and also have noticed, (at least with mine), that the stock, cheapy, Chinese intake gaskets are garbage.

In the past i have just cut my own from thicker, decent, sheets of gas/oil proof gasket material with my trusty exacto knife.

Take the carby with you to an auto parts store to get the viton O ring and match it to the throttle body where the intake slides in...If it still does that after this you will be looking for base or head gasket leaks most likely...DAMIEN
 

Chainlube

Well-Known Member
Joined
Jan 5, 2020
Messages
6,251
The easiest way to get an air leak is for the carb to be resting on the clutch cable mount, not all intakes are created equal. I've had a couple of those and just pulled the holder out and put a plug in the hole and made a remote for the cable.
 

Chainlube

Well-Known Member
Joined
Jan 5, 2020
Messages
6,251
If it's the bike in your avatar, you don't have what I'm thinking. The big screw that goes into the case that the cable runs through, I've had those fowl the carb before.
 
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