1998 cbr 600 f3. Ok compression reads 40 0 0 90 mechanic said bad valve seats at the least. Should i get new valves or a new head or a new motor all together? If new head, can i frankenstein with other cbr generations? I know u can with a lot of their cars. Also how much do i need from an F4i to do a motorswap to injected.

 

Mechanic answered a lot of that for me. He said he can shim the intake valves but he cant gaurentee that it will work fine. Im not rebuiling the engine. I dont have the funds, tools or knowledge for a rebuild

 

Though ive not needed to re-shim my cbr, valve shimming in general is a pretty simple process. It shouldnt be too bad of a process for you

 

I don't understand how you got 0 and 0 for your two middle cylinders???? And 40 or 90 is not good compression either, it should be 160-190 across the board. Shimming isn't going to fix that low of compression unless there is NO clearance between your valves and shim buckets and your valves are constantly open.

 

You can't diagnose something when everything else is out of spec. Set the valves correctly and try again then go from there.

 

I guess from what i understand, the valves werent closin so the fuel and air couldnt be compressed for the spatk.

I dont know exactly how they work. Just hope the bike is ready today

 

Do you know what the valve clearances were/are?

 

Nope i think previous owner did a valve job and forgot to do the intakes. He said all exhaust valves were perfect and intakes were messed up

 

I don't believe anyone who was able to reach the valves and attempt the job would be able to miss half the valves. Hopefully a reshim fixes it...

 

Got bike back yesterday. Compression jumped up to 210 215 212 217. Fires right up.

Mechanic said this is the last time it can be shimmed. But also said its got stage 2 or 3 jetting, done correctly. He said it was so