Yes, like Bigfeet, I was hearing some unusual top end noise. Sounded like a loose valve adjustment. But after checking all that and my cam chain tension, I zeroed in on the advance cover as to where the noise was coming from. Found the side play, started the motor with the cover off and it was more evident. So I put my finger right on the nut on either side of the advancer and held the movement to a minimum and the sound went away.
On another thread, I found where Retiredgentleman had put a shim between the end of cam and advance wheel. I'm going to do that tomorrow.
I noticed mine had quite a bit of end play. I could pull the rod out on the advance side and see it move. When I released it, it snapped back in with an audable "click".
I thought this might be happening while it was running and adding to the top end clatter. It wasn't easy to measure, but near as I could tell, I had about .015" end play. I shimmed it down to about .005". You can't go too tight or the advance rod won't advance - it will bind up when you tighten the disc down. Check it by rotating it by hand.
Well, this didn't do anything for the top end noise but the bike seems to run
smoother. Now with a timing light, the marks don't seem to jump around as much.
I think this stabilized the timing and the advance curve a little bit.
A buddy of mine stamped me out a few shims at work in various thicknesses. I was
ready to buy some from McMaster-Carr and now that I know they do something, I
just might. A standard 1/2"I.D. size works. The rod is 12 or 13mm O.D. (I don't
recall exactly). They have metric ones in 12 and 14mm I.D.s but these only come
in 50 pks., way more than you need. The American sizes come in 10 pks. A pack
of .006"s and one of .002"s would allow you to shim from .002" up to way past
.020" in .002" increments. The 2 packs would cost you about $8, just like
buying a set of points. With the rod removed, place the shims on it behind the points cam. Re-assemble and check by hand for binding and end play.
This may be possible the way Hugh cuts and welds the cams he does. But I had mine done by mriggs. He drills dowel holes in the sprocket shoulder then splits the cam through those holes. In using dowels to put it back together, I don't see it getting shorter.
I checked my other bike yesterday evening and it has almost the same play, but I don't hear any noise like on my new build. I think the reason may be the width of my tanks. Old bike, top end completely covered. New bike, you can see the outer head acorn nuts. I think this is probably pretty normal noise wise, and shimming out the play helps with the noise and timing jumping around. I'm going to shim it up some and report back.
I just made a shim of .015" and put that in behind the pamco pick-up wheel. I have between .003 and .005" free play now.
I also didn't like how the magnet retaining washer was bigger than the 6mm shaft. Hard to get centered and looked crazy out of balance when running. So I turned a shoulder on the retaining nut to center the washer. Nice having a lathe around when you need it.