390xp case match.

[Geraint]

Hello everyone

I have my 390xp apart at the moment and I’ve read that you can match the transfers to the case using the gasket as a template. Could anyone tell me if the part marked in the photo below is the bit that need blending in?

Thank you for any advice.

Ger

 

[Yotaismygame]

The way I understand it is case matching is referring to the part of the cylinder that goes down into the case gets trimmed so it matches the recessed area in the case. Hard to explain without pictures. Do some searching for 372 case matching and you'll find the answer.

 

[Ketchup]

You're pretty much right with the gasket. Just put the gasket on the case and check it before you start grinding anything.

I haven't done a 390, but if I was going to case match, I would cut the flange back to the gasket line as well. It works great on 346 and 372, but I don't know about 390.

Welcome to a great place!

 

[Huskybill]

Match the gasket to the transfer ports on the cylinder, knife edge the center rib for a smoother, more even flow, then match the base gasket to the crankcase.