kz900 strange engine noise

Hi, few days ago my engine start to sound realy weird. I can here some slaping or knocking sound from engine. I cant locate where. I change oil, silkolene 20w50 and oil filter and sound is still there. I check my timing chain, check my carbs on vacum and everything seems to be just fine. Bike has power and works ok. Last year I arranged head, valves and all in relation with the timing chain. Front cam chain guide was broken so I put a new one, so I cant belive that this guide broke again. I didnt change cam chain cos it was ok. Maybe its streetched to much now. I dont know, do this sound like camchain problem? Or maybe sound like starter clutch, connecting rod, crankshaft, piston or I dont know what.

I will put some videos so you can here this sound. First video is when I start cold engine. When engine is cold it sounds ok, there is no sign of this slaping or knocking sound at idle (about 100 knocks in minute).



Second video is when engine is hot and there is that sound in the background (clack-clack-clack...) Above 2000rpm I cant here that weird sound. Just when engine is hot and below 2000rpm.



Does someone got any idea?

Sorry for my english, Ill bet that is better than yours Croatian

your right my Croatian is terrible but your english aint bad! it sounds like the noise you have is at half speed of the engines rpm sooo i would suspect and i could be way off that somethings up with the cam drive. id pull that valve cover and have a look in there. sweet looking bike by the way. fix it before something bad happens to it...steve

cam chain?

At idle, the timing between knocks seems tightly constant for timing chain itself, related yes but seems more as in a camshaft rotation or something that is on a constant/fixed rotation... I would think the chain would have some slap at different/offset intervals...

As mentioned, take off the valve cover and visually inspect... Have a look at the inside of the valve cover, see it you can find where something has been hitting it especially on the cam cap areas (sides).

Inspect the cam end cap areas to see if the camshafts themselves have shifted over to close to on side or the other.

Manually rotate the crankshaft and inspect the shims under each cam lobe.

One tool that is very useful and cheap as well.... I got mine and Kano's at Harbor Freight Tools for $2.99....

I try to listen engine with that stethoscope, and I try long screwdriver also, but I am just even more confused.
If it is a matter of life or death I would swore that the sound coming from the transmission :S But the transmission smoothly selects all the speeds and never happened to fail. Clutch is working ok and sound does not change when squeezing clutch lever. I can here slapping even when engine is in neutral or when is in the gear.
I thought someone would recognize that sound so I do not have to wander about all possible and impossible things about that.
The only thing that is left to check is the cam chain and timing parts. If I dont find anything then engine goes to the reparation table.

It sure sounds like excessive timing chain slapping. My KZ 650 was loud also. I replaced the tensioner with an automatic from a 1981 or later. The tensioner is a double wedge type and works great. My chain is very quiet now. Nice bike! Bob

Sounds like some sort of high spot on the cam chain or maybe two links on the cam chain not swiveling freely from each other. Does the cam chain have a master link? Maybe the master link is slightly larger or wider and is making a different sound when it hits the tensioner or tension strip in the top of the cam cover.

I'm really not in the same league as these other guys as far as engine analysis....just wanted to say that I really admire how beautiful your bike is....hope I can get mine even close to looking that good.

Watch out for those motor gremlins with their tiny little hammers..:lol: Sounds like the oil pump but what do I know...

My kz1000 sounded terrible after the rebuild - until I found an exhaust header that wasn't torqued down correctly.

Syncing the carbs helped a bit too.

I ordered a cam chain and I am waiting to come from z1e.
But I realy think that this isnt sound of bad cam chain. In the meantime I noticed another strange thing. When I hold motorcycle on the side stand or straight it knocks, but when I lean motorcycle to the right side, knocking sound immediately disappears. This is fuc*ing unbelievable.
I realy think that I have some kind of problem with starter clutch. I visually checked the starter clutch, but I think I'll have to dismantle the entire circuit, rotor, starter clutch and gear and review it.
I really dont know what else could be the problem

i listened to the youtube clip before reading the last below staement....and was thinking the same thing,when you had the camera down on the chain cover area i could hear it clearly, the starter gear or a bolt working free in the alternator,stator and cover ect.. or somthing like that.....when you pull that cover i bet you see the grind spot and culprit....any shavings in your oil???....unbelievable bike...just really...really niceOldSchoolHr wrote:

I ordered a cam chain and I am waiting to come from z1e.
But I realy think that this isnt sound of bad cam chain. In the meantime I noticed another strange thing. When I hold motorcycle on the side stand or straight it knocks, but when I lean motorcycle to the right side, knocking sound immediately disappears. This is fuc*ing unbelievable.
I realy think that I have some kind of problem with starter clutch. I visually checked the starter clutch, but I think I'll have to dismantle the entire circuit, rotor, starter clutch and gear and review it.
I really dont know what else could be the problem