Having Problem Engine Noise?

Any help will be greatly appreciated, I have a 1982 KZ750 Spectre, it has 12,000 miles on it, excellent shape it looks like its 6 months old (not almost 30 years), the engine ran great with the exception of a small tic noise from the engine and a little smoke if you cranked it up past 8000RPM. I decided to rebuild the top half of the engine, compression was a little low 120PSI so I’ll re-ring it check and adjust the valves, I’ve been a Tech. for about 30 years now (cars though not bikes) but an engine is an engine, tore it down found the valve guides and cylinders were bad so I went a little overboard sent out the head and cylinder block had new guides, valves and springs installed as well as reseating the valves. The new rings turned into a set of Wiseco 3mm over pistons the kit is really nice brought it up to an 810cc plus raised the compression ratio to 10.25 to 1 from stock 9.5 to 1 did all the work myself aside from the machine shop work adjusted all valves with the correct shims for clearance. The bike’s been back together now for a few months I’ve put about 1500miles on the build and all is well, runs great no smoke pulls hard right to 10,000RPM starts right up don’t need the choke for the first ten minutes any more and you can feel the little extra boost from the pistons even with the stock exhaust on it. Now that you have the bikes history here is my question the tic is still there it is hard to diagnose because you only can hear it when under a light to moderate load you can’t reproduce it in the shop at idle or at 2000RPM, 3000RPM or even 4000 to 5000RPM no tic, if you put a real heavy load on it you can’t hear it either I’m not sure that may be because the exhaust noise may drown it out, it almost sounds like a header tic from an old big block Chevy but I’ve eyeballed the pipes and replaced the copper exhaust rings, I can actually use the throttle and turn the tic on and off by manipulating the throttle up and down or wide open, no one here I can go to for help on this locally so if any one has and idea or has seen this I could use the help thanks.

Exhaust leak would have been my guess. I have one side that will leak no matter what with only one gasket, I have to put in two on the right side or I hear it.

The other thing could be a lifter. On mine, the inside surface of one lifter was rubbing on the valve spring and it made a high pitched metallic sound at idle that drove me crazy for a while.

You need to get somebody else on the bike revving it to get the sound so you can use your ears to localize the are it's coming from.