Honda Spree and Elite 50 Forums

Hey, new to the forum but been referencing here for a long time.
I'm having an issue post big bore that I've never experienced: No matter what jetting I run the scooter always seems to run lean. I can even jet to the point of it hardly being able to run and it still gets hot at anything but idle.
Currently running the NCY 82cc big bore kit with a 24mm Polini carb, the jet sizes are 55 and 135 respectively. The scooter also has a bigger intake and high flow exhaust on it. The fuel is currently 40:1, but I've also tried 32:1. My spark plug is an NGK B9HS. Currently checking head temps with a thermostat that goes on the spark plug
If I'm missing any more important details let me know, thanks!

Greetings:

Your symptoms are very suspicious for an air leak. If you can get to idle, spray something flammable (Carb cleaner?) around the intake manifold, base gasket, head gasket and don't forget the crank end seals. If the idle changes speed you have your leak.

Wheelman-111 wrote: ↑Sat Apr 30, 2022 4:44 pm Greetings:

Your symptoms are very suspicious for an air leak. If you can get to idle, spray something flammable (Carb cleaner?) around the intake manifold, base gasket, head gasket and don't forget the crank end seals. If the idle changes speed you have your leak.

I'll give that a try tomorrow, thanks for the advice!

Saturn wrote: ↑Sun May 01, 2022 4:27 pm

Wheelman-111 wrote: ↑Sat Apr 30, 2022 4:44 pm Greetings:

Your symptoms are very suspicious for an air leak. If you can get to idle, spray something flammable (Carb cleaner?) around the intake manifold, base gasket, head gasket and don't forget the crank end seals. If the idle changes speed you have your leak.

I'll give that a try tomorrow, thanks for the advice!

Update: It was the crankshaft seal behind the variator. Thanks again for the help!

Greetings:

Glad you found it. Not too hard to replace?