Rattly 1986 GPZ750

[jj-taylor]

Gday again,

Need a bit of info if anyone would like to comment, My 86 GPZ 750 runs well and has a heap of grunt and will rev through the range smoothly and with a heap of pull, it apparently has had a new set of barrells and pistons put on it not so long ago but at idle it rattles and sounds sloppy, clutch in or out makes no difference. I have put a manual cam chain tensioner on it so I'm assuming its not cam chain related and it appears not to be valve clearance as the noise is down low. So my question really is how bad can the final drive chain be before it is too bad??? Horrible noise but apparently even after replacing these chains the noise can return quickly.

Any help greatly appreciated!!

Cheers

Jethro

[Ozjavelin]

I've done basically the same work with my '82 GPZ750 and it too sounds like a coffee can full of rocks when cold ..
.. I've been wondering the same question about the final drive chain myself.

[h.b.bear]

Gos will be able to tell you for sure but what i can understand it is a common occurance with these bikes ,i read somewhere if you change your grade of oil it will help a little, but once again i only read this somewhere

[MickLC]

Balancing your carbs can also stop some of the rattle

[Lurch]

Balancing your carbs can also stop some of the rattle

What he said

[bonester]

Sounds like primary chain. If it is the older GPZ750- looks same as turbo 750 then it has a primary chain. If it looks the same as GPZ900r then it doesn't. Primary chains make noise on these engine. Lotsa work to fix. I wouldn't worry about a loose primary chain.

[Gosling1]

My 86 GPZ 750 runs well ... but at idle it rattles and sounds sloppy..... the noise is down low......

It won't be your final drive chain - not at idle anyway

This is the water-cooled 750 eh ? baby brother to the 900R ? The general reason these old motors make rattly noises down low from the r/h side of the motor - is due to the tensioner failing on the balance-shaft chain. The balance shaft on these motors is chain-driven, the tensioner wears out over time, is almost *never* replaced - and gets noisy. You should fix it.

In the unlikely event that this is the older air-cooled motor, the main reason for bottom-end rattle is the primary chain. These get sloppy with age, but in almost every case, if you pull the clutch in the noise dissapears. From your post, it sounds like this noise doesn't go away when you pull the clutch in ?

......Balancing your carbs can also stop some of the rattle......

+100%. This should be done anyway if you don't know the last time it was balanced. Can often make a big difference and quieten down the noisiest of motors.

[jefflthomas]

This is the water-cooled 750 eh ? baby brother to the 900R ?

we didn't get that bike here...

does it have the same starter-generator chain tensioner problem as the big brother?

[bonester]

We didn't get it here officially either- Jap import.

[Gosling1]

This is the water-cooled 750 eh ? baby brother to the 900R ?

we didn't get that bike here...

does it have the same starter-generator chain tensioner problem as the big brother?

.....We didn't get it here officially either- Jap import......

That's the one Jeff. Has always been the subject of intense speculation that Tom Cruise actually rode on of these - a 750 - in Top Gun, and *not* the 900R - something about the paint scheme ?? I think it has been done to death though..

Bones - pretty sure these were officially imported into Oz at the time, although only in small numbers. I knew a couple of blokes back in the mid-80's who had 750R's, and neither of these guys were the *importing* type......but they sure are thin on the ground these days....

[GPZNUT]

I had a Kwaka dealership back then and we sold a few of the 750R's ,they WERE imported by Kawasaki, beats me why they wanted them instead of the 900 though , they were only about $2-300 cheaper,
And for those interested , we replaced the primary drive cush drive rubbers in the aircooled GPZ750's to quiet them down.

[Gosling1]

....And for those interested , we replaced the primary drive cush drive rubbers in the aircooled GPZ750's to quiet them down.....

I'll keep that one in mind - although these are probably NLA from Kawasaki Oz......one of the punters here replaced the primary chain in an old Z750 not that long ago, it had flogged out so much that it was hitting the crankcase webbing on the inside !

[Strika]

I had a Kwaka dealership back then and we sold a few of the 750R's ,they WERE imported by Kawasaki, beats me why they wanted them instead of the 900 though , they were only about $2-300 cheaper,
And for those interested , we replaced the primary drive cush drive rubbers in the aircooled GPZ750's to quiet them down.

Yep agreed. Sold a few used ones and traded a few in when running a Kaw dealership in mid 90's. They were definately an Oz Kawasaki import, not a japanese import. I've eyeballed the compliance plates enough times. Also had a mate with one. They were a PFG bike. I liked the motor more than the GPz900R motor.