Minimum mating surface?

[2stroketunah]

Hello,

can anyone tell me what the minimum MM in mating surface is needed for a proper seal of the crankcase.


I cut my case to fit a bigger crankshaft but now the case halfs only have about 1.4mm or mating surface.


is 1.4mm of mating surface enough to make a good seal for the case halfs?


any help greatly appreciated 

[oldgeek]

1.4mm is not very much to make a good seal, but it could be enough. Assemble it, do a leakdown test and see.
What kind of cases are you working with?

[2stroketunah]

thanks for the reply.

its a yamaha Jog 3Kj engine.

building 90cc 2fast setup.

I cut the case for the crank but mating surface is now much thinner (1.4mm) hopefully it seals.

anyone out there with experience sealing with this small crankcase mating surface? im sure someone has built stroker 3Kj yamaha engine.