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SOHC timing....please help!!

OK guys thanks for your help - I am a complete numpty!! First bike engine is my excuse. Used to car engines - anyway I had been rotating the engine backwards instead of forwards. so when the inlet valve was closing I had the exhaust opening virtually immediately.
As soon as I rotated it the right way it all fell into place - what an idiot I am - he ho - they reckon you learn by your mistakes

Appreciate the responses though and thanks again.
 
Grinding valves and lapping are two different operations. I was referring to having the seats cut with new correct angles and valve seat margin and concentricity for proper valve seal on the new valves. Its generally best practice to have seats cut if new valves are used...new parts=new machined surfaces. Valve lapping will work but chances are your contact margin is way too wide which can cause issues. Did you change valve guides? Exhaust are generally bad if there is mileage enough to warrant valve replacement.
 
Grinding valves and lapping are two different operations. I was referring to having the seats cut with new correct angles and valve seat margin and concentricity for proper valve seal on the new valves. Its generally best practice to have seats cut if new valves are used...new parts=new machined surfaces. Valve lapping will work but chances are your contact margin is way too wide which can cause issues. Did you change valve guides? Exhaust are generally bad if there is mileage enough to warrant valve replacement.

Dirtdigger, the valves weren't that bad - I just wanted to replace them as I had the engine stripped - your terminology is different to mine, we often say grinding valves in instead of lapping - but the valve faces in the head were fine.
This is not the first head I have had to deal with just the first bike head, I recently did an MGA engine and the valve seats had been cut so deep I had to have new seats inserted. When I lapped the valves I was checking the amount of surface area being worked and it looked fine to me, in what has been my experience.
I didn't change the valve guides as again there was n't anything suggesting they needed changing.

I spoke with a guy who sells and rebuilt and project bikes here in England and he said he hardly ever has to do anything to these engines. Mine ran fine before I took it apart - but it hadn't been on the road for years so it seemed sensible to check it out by removing the head and cylinder block. As it turned out I could have left it all but at least I know for sure now it is OK.
I appreciate the advice and suggestions made - all good stuff and I expect as I get the engine back in the frame and get started on the rest I will no doubt have other queries
cheers
 
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