No, you can change the countershaft seal and shifter seal after the engine is installed, if necessary.

Yamabond, Three Bond or Loctite flange sealant, like 518 would work well for the case halves.

Is there a preference of the three? And as for what seems to be left of existing seal on the two halves, just take a razor blade to them or something else?

Be careful with a razor, as it could easily gouge the aluminum. I use the back edge of a razor, since it is stiff without being too sharp. With nitrile gloves, you could also try a small stainless brush and some acetone. Beware of fumes.

I don't have a preference between the three flange sealing products. Whichever is cheaper.

In good 'o days those aerosol gasket remover contains loads of DCM which is very efficient :clap:

Alright, finally got the two halves of the crank case cleaned up and put back together. I'm getting ready to order parts and need some input. A while back i picked up a complete top end. Cylinder, head, valves, cam, sprocket, the whole nine yards. Basically should I use my original cylinder and just order the parts i need, or should i just order a bottom seal and a set of piston rings for the complete top end. The original low compression has me a little worries that i'm going to get this thing put back together and still have low compression. Thanks for your help and advice.

m0t0

I can't believe I missed your last post; if you're still watching this, please clarify what you mean.

Are you asking if you should reuse your old cylinder? If you have a new one, I'd just use that. Before installing the new cylinder head, I'd set it upside down on the bench, and fill the chamber with acetone, paint thinner or whatever. Let it sit overnight, and see if any leaked past the valve seats. If not, you have a winner. :D