Topic: Piston/Valve Interference?

[TOOLS1]

I just installed a cam out of a 76 K, and now it feels like the valves are hitting the pistons right at the (T- top dead center mark). Any body else had this problem?
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[raymond10078]

I can't speak to this personally.

But . . . your situation doesn't make sense to me.  I have talked to others that have done exactly what you have done - with no problems.  The pistons differ from the K bikes (to achieve the lower compression).

I may be confusing you with another - but was this an otherwise stock bike or was this a previously modded bike?

[TOOLS1]

I found the problem, actually three problems. First the line on the cam was stamped out of center. Second was the stretch in the cam chain. Third I think it is an aftermarket cam. I can't find any markings on it though. However the bike it came out of had a lot of modifications, including a Maxi-dwell points plate. Because of the stretched cam chain, and the line stamped off center I had it a tooth out.
So the A has lower compression pistons. Is there any difference in the heads between it and the K? Also what happened to the rest of my post about the gearing changes?
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P.S. Why do I have to type in the funny words in the box to post here?

[raymond10078]

The heads are the same as the K bike.  Both models share the same Honda part number for the head:  12200-392-000, which is common to the following bikes:

76-78 CB750A
76 CB750F
77-78 CB750K

In regards to the rest of your post - my fault - they were accidentally deleted during the move.  Sorry for that.  You said:

• I have found the quickest, and easiest performance improvement is to install a 16/48 sprocket combo with a 530 chain. I often ride with a friend that has a slightly modified 1978 CB 400. He can get some lead on me in first gear, but while he is shifting into second I am gone! And I can still do the TON.

If you could cut/paste this into a new post in that thread - I would appreciate it.  I can't fix my screw up without your help.  HELP!

I think the answer to the last question is only because you haven't posted much on this site yet.  I believe that you only need 5 posts to get rid of that nuisance.