Top end of first gear haemorrhages?

[MSTRS:Me]

I've tested for smoke leaking out of the wires, and there wasn't any. Time for a new approach.

The clattery rattle racket it makes while running, while possibly some valve noise, is most likely the timing chain. The tensioner is at full stretch. Not good

If it jumps a tooth would it run, or run noticeably out of whack? Yes to both
If the chain is flailing round and hitting things, could that be the problem?

Or you sure that all valves are closing fully? Reduced compression would have it bogging down.
Change the oil. Capture and strain the old oil and check closely for metal filings. If the camchain is loose enough to touch things...well, you can be assured that it is grinding them away. Had a CB100 do that back in the 70s and before I know what I know because of it.

[Staticam]

Or you sure that all valves are closing fully? Reduced compression would have it bogging down.
Change the oil. Capture and strain the old oil and check closely for metal filings. If the camchain is loose enough to touch things...well, you can be assured that it is grinding them away. Had a CB100 do that back in the 70s and before I know what I know because of it.

I think the valves are closing - I can get a feeler gauge blade in there. I'll do a compression test. There certainly was filings in the oil but that was due to the starter clutch bolts. I haven't looked recently. Somehow I think I knew I should have done the timing chain when the sprag was getting fixed. Take the motor out again I guess...

[Staticam]

Reduced compression would have it bogging down.

Compression test showed up 85psi cold (throttle closed, oops). I don't know what it should be except 7.8:1 ratio.

I took it past a couple of shops to test their ear and get their opinions. First one wanted me to leave it (along with an open cheque book I guess) so they could pull it apart for a closer look. The second thought the valve train might be trashed. Both agreed that it isn't making happy sounds.

I'm getting a price for a timing chain, guides and associated gaskets.

I wish I could just throw another motor at it, if it were just that easy... someone might know what might fits.

[MSTRS:Me]

Compression test showed up 85psi cold (throttle closed, oops). I don't know what it should be except 7.8:1 ratio.

Seems very low. I would expect to see somewhere over 120psi , probably 150-ish
Badly seated valve?