Folks,

Replacing a leaky base gasket, rear cylinder, stock 94 EVO, 30k miles. Everything looks good on the head, cylinder, and piston. I am going to reuse everything. Question is: Do I have to and should i use a ball hone to rough the surface of the cylinder slightly in an effort to allow the rings "reseat" themselves to the bore? This is the first time i have been into my bike this far. Any recommendations here would be appreciated.

 

Do not hone the cylinder

 

Don't hone if you aren't replacing the piston rings. But I'd likely replace them while I'm in there. And I would also check piston deck heigth and use base and head gaskets to achieve the proper gap between the piston and head. Especially if the base of the cylinders need to be cleaned up any to get them strraight (see below).

You need to check the cylinder bases to be sure they are true so the new gaskets will seal. Also check the cylinder studs to be sure none of them are coming lose.

Paul

 

Cylinder base has been trued up, I have the James gaskets. So if i reuse the rings then put it back together? No hone?

 

Yes. But at 30k miles, I'd replace them as they are not expensive and the work of getting to them has already been done. And I'd replace the valve stem seals and likely have a valve job done too.

How much was removed from the cylinder bases? I'd still check the deck height while things are apart, especially considering the cylinder bases were cut and it's a good time to set that up properly. It's easy to do and other than time, mostly free.

Paul

 

just a skim .002"

 

Likely just fine with only .002 removed.

Paul

 

the guy that cleaned them up said if they were really bad and he had to take too much off i would have to tear off the front and get that one done as well. The bike ran excellent, just the leak at the base. I'm not sure where i am going with this bike but right now i'm looking for at to run like it did and be reliable.

 

Ok, that makes more sense since you are only doing one cylinder.

Paul

 

No hone.. If you are using James sillycone beaded headgaskets, you'll be back in after another 20-30K.