Breathing noise with Mikuni upgrade

How is it on the pull rope? Is it still tough to spin over? I wouldn't run it too long like that. Improper valve lash could be causing your issue
Glad you found the air leak
The pull rope is fine. I don’t think it’s an issue with the valve lash, more with the carburetor. I just don’t know why the bike dies when the enricher is off. I’m not sure if there is another air leak.
I'm still suspecting air is leaking in at your manifold gaskets. So much so that enriching is only way to meet fuel needs.
Is there anyway to test to see if the issue still is an air leak. I think Minimichael is right, and even though I removed the black seperater gasket, I still think that air is leaking which is causing bike to die when enricher is off.

*Edit: I'll spray some carb cleaner to see if there is a change in rpm at idle, to hopefully find an air leak.
Last edited:
so the biggest jet that comes with these carbs is too small, it's like a 90. it's cutting out at high rpm because it's too lean. your elevation will be dependent in the end of how big a main jet you really need but the standard size I always start with on those carbs with a basic stage 1 motor is a 120 main jet. I never have to mess with the pilot that comes in the carb, it always does fine, only mess with the fuel screw on the bottom in order to achieve best responsiveness off idle.
The bike was backfiring blue flames out exhaust yesterday cus I had fuel mixture screw tightened too much. I loosened the screw more so its at 1 3/4 turns. The bike still backfires when I let off throttle, just not with the flames. Is this normal?