KZ750N2 Spectre Engine rattle

[pipes66]

Ive got a noisy rattle at idle on my 1983 KZ750N2 Spectre.The carbs are clean and I thought it was a balance issue causing the noise so I sync`d the carbs,it made it slightly better.I was a bit worried that it was a crank problem but if I put her in gear and let the clutch out a little with the back brake on the noise goes away.Is it a bad cam chain tensioner?

[sheldonbourgeoi]

Is it a rattle sound, or more of a "chucka-chucka chucka". These engines, as they get a few miles on them, will omit the "chucka-chucka-chucka" sound at idle. It's caused by the primary chain slapping around a bit which is due to the fact the chains stretch a bit. It's totally fine, and synching the carbs, having no vacuum leaks, and setting valve clearances makes it better. As the engine warms up it should all but go away.

If it's a really rattly noise then it's more than likely the cam chain. The automatic tensioners suck. I installed a Krieger manual tensioer on my GPz 750 2 years ago and it hushed all cam chain buzz and I haven't had to adjust the setting since. The Krieger was very well priced, comes with simple directions for installation and the needed gasket. Regardless of if you need it or not, I'd suggest putting one on, to be safe.

kriegercamchaintensioners.com

[pipes66]

I have ordered one already from Mark @krieger ,what do you reckon regarding putting it in gear and holding the back brake on though,if the noise stops does it suggest cam chain tensioner? I guess its hard to tell without hearing it and I imagine having it in gear would stop the primary chain rattling as well....

[sheldonbourgeoi]

Kawasaki Air Cooled GPz750 ZX750-A3 - YouTube -At 50 seconds onwards you can hear the primary chain making the "chucka-chucka-chucka" sound.


Kawasaki zx-6r automatic cam chain tensioner - YouTube This is the sound of a bad cam chain tensioner. You can hear the cam chain slapping off the engine case.

[pipes66]

Both those vids are the same is the cam chain noise on that one too?,my noise is the chucka chucka though.I havn`t checked my valve clearances yet as I have only just cleaned the carbs and just wanted to get her going.I thought balancing the carbs might do it,does doing the valves quieten it down a bit?

[sheldonbourgeoi]

Funny, I see 2 different links and when I click on them both are different vids.

[sheldonbourgeoi]

Both those vids are the same is the cam chain noise on that one too?,my noise is the chucka chucka though.I havn`t checked my valve clearances yet as I have only just cleaned the carbs and just wanted to get her going.I thought balancing the carbs might do it,does doing the valves quieten it down a bit?

It will quite it down, but it's still going to make a bit of noise when the engine is cold. You'll always get some of that noise, it's just how these engines are. If it really concerns you you could spend $$$ to have the engine split and half and a new primary chain installed, but after a some mileage on the new primary chain it's going to make the noise again.

I keep my bike in top shape. Resealed the carb boots at the engine last year, carbs in synch and valves perfect. Get a wee bit of primary chain noise when cold, but when warm next to nothing. I may be the exception. The guy in the YouTube vid I linked, his Gpz looks immaculate and the idle is nice and steady, but still hear primary chain. As I said, it's the nature of the beast and won't harm the bike in any way.

[sheldonbourgeoi]

It will quite it down, but it's still going to make a bit of noise when the engine is cold. You'll always get some of that noise, it's just how these engines are. If it really concerns you you could spend $$$ to have the engine split and half and a new primary chain installed, but after a some mileage on the new primary chain it's going to make the noise again.

I keep my bike in top shape. Resealed the carb boots at the engine last year, carbs in synch and valves perfect. Get a wee bit of primary chain noise when cold, but when warm next to nothing. I may be the exception. The guy in the YouTube vid I linked, his Gpz looks immaculate and the idle is nice and steady, but still hear primary chain. As I said, it's the nature of the beast and won't harm the bike in any way.

Kawasaki Spectre kz750 - YouTube You can hear the primary chain,e specially when the idle is low.

[pipes66]

Ive made a video and uploaded it on youtube,how do i put a link to it on here?

[pipes66]

I hope this works,this is with the idle quite low.

KZ750 engine rattle - YouTube

[sheldonbourgeoi]

That's definitely your cam chain. Don't run the bike anymore until you get the Krieger installed. When it comes time and you need help, just message me.

[pipes66]

Thats a weight off my mind!!! Thanks a lot for chatting,may be a week or 2 comin from the states so i`ll re-post then.All the best...

[pipes66]

Manual CCT fitted.Bike a lot quieter now although still got a primary rattle on tickover.Other than that ,sweet as a nut.

[thejij]

Rattle.. hrmm.. okay I have a 750 N1 .. and its not really a rattle.. its more a really bad noise !!! Sounds like its in the bottom end. I have already replaced the CCT with a kreiger (awesome btw). If I post a video.. will someone have a listen and advise?? thanks