My bike wont idle properly when hot

Trevor

New Member
Jul 2, 2016
3
0
0
CA
Everytime I ride my bike for like maybe 5 or 10 minutes, when I pull the clutch in my bike will start revving really high and the revs will starting bouncing. I've got the NT carb by the way. I have tried adjusting the idle screw but it's either too high or dying no matter how I adjust it. I'm thinking maybe it's my offset intake manifold causing the idle issues or possibly an air leak but nowhere on my intake manifold is there oil leaking and I tried using propane to find an air leak but didn't really see the idle change from that. Help! I have no idea what to try anymore
 

Slogger

Member
Sep 8, 2014
545
4
18
nohio
Hi Trevor.
When these engines rev up like that it's almost always an air leak, so I think you're on the right track. It's important to make sure the NT carb is pressed firmly over the manifold, there are two big gaps that can leak if it isn't seated all the way.
Next I would put some sealant goop on the manifold connections, whether you can detect a leak there or not.
Then torque the head down good and try it again.
And make sure your throttle slide is in right and travels freely up and down.
That's the stuff I would look at first. If this doesn't help you could pull the side covers off and look for oily residue on the coil or the drive gear. It might have blown a seal.

Good luck and hope you sort it out.
 
Last edited:

Trevor

New Member
Jul 2, 2016
3
0
0
CA
I've got a new intake manifold gasket on the way. I think I might try to get an o-ring too for the manifold-carb connection and I'll see of I can file it more flat too. Is there anywhere else that could really leak and cause this?
 

Slogger

Member
Sep 8, 2014
545
4
18
nohio
Yeah, the cylinder to cases joint, the split case joint, the seals, and maybe the exhaust to head joint but people run them without a pipe so that can't be it.
I have one of those o rings in the carb mouth, don't know if it helps much.
You can use permatex copper gasket sealing stuff to make sure, it works well for me.

The face of the manifold flange can be smoothed and flattened with the old sand-on-a-pane-of-glass trick.