What is that noise?

I have a 1980 KZ 1000 LTD. Upon start up the engine is quite. However after about a 20 minute ride it sounds like the the valve or timing chain is making alot of noise. You only hear it in the top end. I tend to think it is the timing chain as the noise is constant and not a tapping or rapping. Any suggestions would be appreciated.

i am having that problem with my 74 z1 90. I think it is the cam chain rubber parts that have deteriorated over the years. Maby someone one here with some personal experiance can chime in.

have you trid to adj the cam chain to see if it goes away

I have been struggling with a mystery noise for years now. The best thing I did to help figure it out was purchase a mechanics stethoscope and use it to pinpoint the location where the noise was the loudest. Turns out my clutch hub springs were rattling around in their housings.

The typical low rpm death rattle is often reduced by carb sync and pilot mixture adjustments (preceded by first assuring all valve clearances, can chain tension, and ignition timing are up to specs, and new plugs).

As known, carbs should be addressed last because carb performance is dependent on all the other components. Even perfect carbs can't and won't compensate for other components being out of spec.

That is GREAT advice. I use almost that exact statement in the disclaimer part of my ebay ads for carbs that I rebuild and sell for other bikes. I learned that lesson myself on my kz. My WG BS34's did make a substantial improvement, but it didn't fix my mystery problem.

All three of my bikes do that. It sounds like they have a magneto with an interruptor, the way they clatter. I pulled one engine apart twice looking to see what was causing the noise, no joy. I used a stethoscope but it did not help pinpoint the rattle. Now, I just ride the bikes. If it is something serious, I will find out what it is when it breaks. The milage on the bikes is 22000. 38000. and 46000. chris3