So,  I got my cylinder bored (CT3), have a new piston w/rings. I took the engine off the frame and flushed the crankcase of whatever little black crap was down in there with some premix.  Before I install everything, I tried a leak down test without the new piston, just the jug and head with a brand new oem head gasket.  I am roughly losing two pounds of pressure per minute from the head gasket from two leaks near the bolts on the clutch side.  I sanded the head surface on a glass plate with 800 grid paper which made little difference.

I was wondering if it matters that the piston isn't installed or that the engine is stone cold or that the head gasket has never experienced running temperature.

Also,
can any machine shop flatten the head surface?
is there a specific term for flattening a cylinder head?
if the head was warped from over heating is it possible the cylinder could also be warped?

Thanks for listening. 
Rob





 

If it were me I'd take both head and cylinder to a machine shop and ask them to check them to see if either are warped and if so then true them up.

I’ve had 4 CT’s and 2 AT’s. Never had any head or cylinder warped issues. I would put it back together and torque the head and go for a ride then let it cool down and retorque again 2 or 3 times heat and cool cycles 

If it were me--& i'm never sure if i'm me today--i'd anneal the head gasket to soften the copper now it's been squashed, & then wipe grease over it & torque it down. I guess you got a 175 gasket & not a 125 one by mistake--same stud pattern. Be careful annealing because by memory 175 gaskets are quite thin.
Piston has nothing to do with head leaking.

Why not true the cylinder surface on your glass plate?

Anneal gasket is a good idea.

K&W Copper Coat works good on head gaskets. 

Thanks for all the advice.  I just shipped out my head and cylinder to Bill Bune. Local machine shops just give me the stink-eye when I show up with a motorcycle part.
 

Hope they don't take too much off but probaly not or you might need to run two base gaskets or make a bouble thickness one. I hate making gaskets but do if i have to.