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80cc carb set up?

Posted: Fri Jul 13, 2018 11:34 pm
by Ncp546
This may be completely wrong or potentially not true ( have not measured the bore myself) but I purchased a spree that I was told was bored out to a 80cc. Its the stock cylinder 49 but he was a machinist and did the work himself. The spree than sat for 2 years and our ethanol fuel we have gummed up the carb. I then cleaned out the carb and now for the life of me cannot get it to run good. Stock carb, stock air filter. He told me to back the air mixture screw out incredibly far. But after tinkering with it for a few days now im at a loss. Im starting to think I need a different carb. 91 octane running 32:1 with a new spark plug, new cdi and coil. Any help would be appreciated. :thumbwink:

Nick

Re: 80cc carb set up?

Posted: Sat Jul 14, 2018 6:47 am
by Meatball
To achieve 80cc on a Spree with a stock stroke, youd need a 52mm bore. I call :bs: on boring the stock cylinder to get there. Even then, youd never get the stock 13mm carb to work with 80cc.

Typical story here. Guy tries random things to make his scoot faster...it doesnt work and sells it.

Re: 80cc carb set up?

Posted: Mon Jul 16, 2018 6:59 am
by cancunia
Backing out the air screw will make the mixture leaner. What colour is the spark plug after you've had the engine running? What notch is the carb needle on? What size jets do you have?