Rythmic/cyclical tick - 1980 750 LTD 4 cyl

Hi guys,
I noticed an odd noise the other day while riding. At a stop light at idle, I could hear my cams ticking a little bit. Nothing out of the ordinary. Then I heard it get a little louder and then quiet down. Then 4 sec later another cycle, identical to the first. It kept sitting there, every 4 seconds, ticking a bit louder. RPM's unchange and the bike runs fine. BTW, it's a 4 cylinder.

I figured this is really odd, because everything is spinning much faster than the noise was cycling.

Any ideas? Yes, I checked clearances at the beginning of summer, about 2k miles ago and were midrange spec. Oil is 20-40 (or 10-40 can't remember) valvoline motorcycle oil w/ 2k miles on it.

Check for exhaust leaks. Also check for a loose spark plug. (Don't ask how I know that)

lol, I won't.

It just seems so weird with the slow cycle rythm....

Instinct (sometimes wrong) tells me it's oil or oil pump related. I would start by changing the oil, it's time anyway at 2k miles, and I would put in Mobil-1 Racing 4T 10W 40 motorcycle oil (see link) to see if problem dissapears. Ed

Oil

Thanks 650ed.
I was toying with the shell rotella T at wally world too. Some people seem to like it, but I just feel more comfortable putting motorcycle oil in mine. Just gets a bit $ if you put lots of miles on.

This is a synthetic, right?


Would it make any sense to put an oil pressure gauge on that fitting down by the rear brake pedal to see if the pressure changes with the noise?

Yes, it's full synthetic, it has the correct level of ZDDP, and it is made for wet motorcycle clutchs (unlike regular car Mobil-1). I've been using it for several years and it works great in my bike. Ed

i use royal purple max cycle in my kz, runs smooth as you could ask it too. it also runs about 30 degrees cooler too. good luck and have fun riding!

you may want to check the cam chain if the noise continue's after changing the oil. Mine had a noise close to what you are describing and after a couple of months of it the cam chain broke. Very bad thing. I found the automatic tensioner stuck and caused the problem. Since my rebuild I went with the APE manual tensioner and couldn't be happier.

+ to what Vter Bob said. It could be a slight leak from the exhaust gasket at the head.

I just had the same problem with my 550 Zephyr. Thought the valves were ticking and realized it was a leak from an exhaust gasket.

You may have the old style automatic tensioner, which are junk. My KZ 650 Ltd had one and the chain made an awful noise. I put in one from an 81 or 82. It was a double wedge type,(that can't push in). I've had in for 3 years and it runs nice and quiet. Good luck on finding the cause. I'd still can the old auto tensioner. Bob

Thanks guys, I'll check that out.

Just seems so weird though how slow the cycle takes. Literally seconds inbetween cycles.

I think this Image from the Parts pages will help show you as to whether or not the style you have is the older version.

You can plainly see the difference, as the older style, left bottom, has no wedge from the side.