kz900 strange engine noise

As I read through this tread, with each new pages I was hoping to see that you found the problem. I wish I knew the answer...I don't.
I do have a suggestion. There's been some debate if this is tolerance/clearance problem or lubrication issue. The noise doesn't start until the engine heats up. Heat expands the engine metals, but also thins the oil. The noise stops when you lean the bike. This could be due to changing the side loading on a bearing or other surface. However, it also changes the oil levels inside the cases. Which is causing it to stop?
Try this. Start the bike cold and time how long it takes for the noise to start. Let's say it's a minute. Shut the bike off for 5/10 minutes and restart it. Again timing how long until the noise starts. Everything should still be warm/thin, so it should start quicker. Let's say 15 seconds. Now shut the bike off and change the oil as quickly as possible. Ideally you'd want this to be about the same amount of time (5/10 minutes) as the earlier test. The parts will still be warm, but the fresh oil will not have thinned. If the noise starts closer to the minute, you've got a lubrication system issue. If it comes back around 15 seconds, it's probably a clearance problem.
This may not solve your problem, but it point you in the direction you need to focus on.
Good luck and I look forward to your "found it!" post.

I just want to notify all of you who are interested in this mystery, it seems that I solved the problem. Few days ago I received manual tensioner that I ordered.
When I warm up my engine I tightened manual tensioner while engine was running and knocking sound disappeared. I didnt over tightened tensioner bolt, just as much as is enough with my two fingers :blink:
For every case, I loosened and tightened tensioner few more times just to be sure that is that, end every time knocking appears and disappears...
I do not know what happened, even I do not know if I fixed the problem but I am satisfied for now.

Sorry big guy but this needs to go in the Wall of Dumbass for wasn't this mentioned like in the first two replies and numerous times thereafter? ... :laugh: :laugh: :laugh:


OMR

Good... now you can get a good nights rest, as you were probably losing sleep over it!!!

Old Man Rock wrote:

Sorry big guy but this needs to go in the Wall of Dumbass for wasn't this mentioned like in the first two replies and numerous times thereafter? ... :laugh: :laugh: :laugh:


OMR

It seems so :silly: till the last moment I believed in stock automatic tensioner. It was working excelent, but maybe that spring behind tensioner rod was just to weak.

Maybe I'm miss understanding but my KZ900 OEM tensioner doesn't work that way...

Translation, all the spring does is let it snap forward against the cam chain at ideal tension when the side bolt and nut bolt are loosened (@ TDC 1 & 4 for adjustments)... It doesn't automatically adjust while riding...

Maybe yours is different...

Anyhoot, glad you found the problem.... Keep your fingers crossed...

OMR

Old Man Rock wrote:

Maybe I'm miss understanding but my KZ900 OEM tensioner doesn't work that way...

Translation, all the spring does is let it snap forward against the cam chain at ideal tension when the side bolt and nut bolt are loosened (@ TDC 1 & 4 for adjustments)... It doesn't automatically adjust while riding...

Maybe yours is different...

Anyhoot, glad you found the problem.... Keep your fingers crossed...

OMR

You are right, my tensioner work that way too but obviously spring was too weak to snap forward enough to make proper tension on chain.
Also, when I put manual tensioner first time, I was doing everything by the book. Engine was not running, I found TDC 1 & 4 for adjustments, tightened manual tensioner, turn over crankshaft few times, tightened again...and when I started engine sound was still there.
Just when I tightened manual tensioner while engine was running knocking sound dissapear. And many people said dont do that while engine is running, I dont know why!

Wow, you have a beautifully maintained KZ900 gotta get going on mine she's been sitting for the last year and 1/2 waiting to be put back together and get back on the road. Your most recent video is awesome-some high speed driving, twistys and a beautiful view at the top of the mountain!

This was a great string with lots photos, videos and solutions offered up and a final resolution. I just wish you had kept the videos of the initial noise problems for the future(might help someone else diagnose their problems...). I also checked out your webpage-very nice, I just need to translate some of it!

Aloha from Hawaii,
Jonesy

very nice bike and beautiful ride one question

did u have a problem with ur speedometer cause its bouncing back and forth like crazy?

Happy you found your problem. video, love it. Doug

ditchdriver wrote:

very nice bike and beautiful ride one question

did u have a problem with ur speedometer cause its bouncing back and forth like crazy?

It is probably weak magnet, return spring on the needle or internal damper above that spring. That is happened only at high speed or fast accelerating. In normal drive they are ok.
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