70cc hobbit full throttle revs at idle

I am new to hobbits and tried to get a build going

New 70cc kit. New stock CDI . New mikuni 20mm round slide carb (down jetted.)

It has never been running since the build started

The problem I’m having is it will not idle for more than a few seconds then it starts to ramp up like it’s at full throttle. Throttle cable has plenty of slack. Slide is all the way down. My guess is air leak? I’ve gone through gaskets after gaskets and can’t seem to find a leak, I’ve racked my brain for weeks trying to figure this out. Any ideas why it immediately revs up that high with a new kit?

Re: 70cc hobbit full throttle revs at idle

Definitely sounds like an air leak. Or like your running way way way lean. What jet are you running and does it do it with the choke on?

Re: 70cc hobbit full throttle revs at idle

^^air leak, if its not carb, nor gaskets, then its crankshaft seals.

Re: 70cc hobbit full throttle revs at idle

Yeah it does it when the choke is on. I down jetted to idle to 17.5 and the main 145. Those were the suggested jets for a 70cc kit. I’m thinking air leak is the culprit.

Re: 70cc hobbit full throttle revs at idle

Seems I may have found the leak. Clutch side of the case is dirty with oil. Looks fresh. Gotta pull the clutch off and take a look.

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