Help 61mm bbk too much pressure oil leaking.

[James2132]

I have a taotao 150cc scooter. I just installed a ncy 61mm bbk and after a few minutes of driving I have oil spraying everywhere! The scooter bogs and shuts down. So I just reinstalled my original 150cc piston n cylinder back in till I can get some help. I'm thinking the problem is too much pressure. I bought a ncy decompression tube and there's still too much pressure.

[Wrisberg]

I have a bb 180, heavily modded for more compression, and no spray of oil at all.
Did it starte and ride allright with the bb?
The oil could come from your valve cover, head gasket, maybe?
There shouldn't be much difference in pressure inside, not this much anyway.

[ragtopdodge]

Did you machine the crankcase? Anything bigger than 59mm, u need to do that.