Engine noise ?!?!

HELP!

I have a 1977 KZ650 B1 model. I rescued it from an old farm shed, cleaned it up, put fresh fluids in her and have done a lot of basic mechanical work (carb tune/sync, new tires, steel brake line, new regulator/rectifier, new battery, new chain/sprockets, etc.) to get this bike back on the road. I've taken a few short trips with it with no hassles since putting it together.

This morning, however... it fired right up and I let it warm a few minutes in the 44-degree temps. Got out on the highway and after the first few miles I started to get a high-pitched mechanical squeal from the motor (not a grind or clunk, but a loud sound, almost like a fan belt that's loose or a starter motor straining). Needless to say I pulled off on some side streets. The speed of the bike or the gear I was in didn't change the noise, but after a few miles on city streets the racket dwindled, then stopped. I drove home no trouble and got on a different bike to get to work.

But what the... where do I even start? Anyone had the "unexpected" occour and how did you start to track down the trouble?

I'd start by draining the oil and looking for metal filings. If I found em, I 'd check something easy like the cams. If they're OK I'd get ready for some real work. Sorry I can't be more help.

KZCSI

Did it change the performance of the bike? Does your starter still work. I would check the oil also. I was thinking head gasket leak, but I could be wrong, but retorque your head. Oil check!

After searching this very useful site (and I mean that sincerely!) I found a similar entry... and the culprit was an aging speedometer/tachometer and a dry cable. The noise did subside when i slowed on city streets to 30 - 40 mph and I didn't notice any other changes in bike performance. Maybe it's just the speedometer hub/cable or tach cable that needs some lube. I will try the simple stuff first before I get into a major engine teardown.

Could even be coming from the front end.Maybe a wheel bearing...or brake pads vibrating on the rotor.That speedo issue is for sure another one to look into.

Does this noise occur when the bike is just sitting,idling?
Try to narrow it down,before You start pulling parts AND/OR Your hair...good luck.

The tach and spedo cables will make noise just before they break.If your guage s still work it could be something else.Wheel related noises usually change pitch
when the MPH changes.If the starter clutch is hanging up
it will soon be a kickstart only bike.The starters on
650 kwackers are alot harder to change out than most bikes.Lets hope it's a cable.

UPDATE #1

I think I am losing my starter clutch, or starter completely. When I got home from work today I immediately went to work on the KZ. Turn on the key, turn the switch to RUN, tap the start button... click. click. click. Starter did not turn at all. Flipped out the kick start lever... kick... VAROOOM! Off she went to a nice fast idle with the choke. Let it run a few minutes, gave it some rpms in neutral... no strange noises. Lubed the tach and clutch cables and the speedo drive on the front wheel. Put the bike up on service stands, front and rear wheel spin freely, no wobbles or squeaks.

Let the bike sit a bit, the tried the start button again. Click. Click. Then one or two cranks. But no fire.

Can I just disconnect the leads for the starter motor in the short term and not use it or will this throw off something in the wiring harness?

P.S. -- I also discovered the previous owner had, ah, "customized" the starter lockout switch on the left handlebar by cutting the wires and wiring them together. That may be part of the problem as well. I'll be able to take it for a test run tomorrow and see if my noise has gone away.

My friend has kicked his 650 for years.
Check your wiring,the botched wiring
might be the cause of the noise also.
It might have tried to run the starter
while you were riding.