Compression

[facepants]

Right now I'm testing compression and coming up with none.  The carbs, airbox, and exhaust are disconnected.  Should I still be getting compression without these connected? 

It makes sense that I should, but after all I've done to this bike, I have no idea where else to look.



background:

I had low compression on both cylinders, had them measured.  They are within spec.  So are my pistons.
Had cylinders deglazed and Installed new rings.  Discovered my head was warped and one valve was bent.  Had all valves overhauled at a machine shop and had the head decked.

Put everything back together with new gaskets, and I still have low compression.  I really don't know what it could be at this point.

[facepants]

Another thought...

Do the gaskets need to heat up before they make a proper air-tight seal?  I've read that they have some special coating on them to create the seal.  If I hook up the fuel and run it for a while will it seal off and give me compression?

[Egaeus]

What is your compression reading now? 

Try putting a bit of oil in each cylinder and seeing if it improves things.  If so, the rings aren't sealing.  If it's within spec, I wouldn't worry about it.

[facepants]

Compression reading is 0 on the left and 30 on the right

No improvement with oil on either side

[trumpetguy]

Are you ABSOLUTELY sure about your cam timing?  If it's off, you could have very low or no compression (and the strong possibility of valves getting close or hitting pistons!).

[Egaeus]

Check your valve clearance.  It could be that since the heads were worked over, the shims are too large, and causing the valves to stick open. 

Check your timing.  It could be off so that it's opening a valve during the compression stroke. 

While checking the clearance, make sure that the valves go up and down as the cam turns.  If they don't, I'd find a new machine shop, and see about getting a refund.