GPZ750 Cam chain adjuster

[Eastoe]

guide inside cover

[h.b.bear]

Are they the original cam sprockets? and are the cam shafts been fitted properly if they have the only other thing id try turning your rocker cover around. Now I know your not that stupid so disregard my theories and wait for the almighty Gos !! He will know

[Gosling1]

....Are you running the cam chain under the center roller or on the top? It's meant to run underneath.....

.....This model doesn't have the centre roller of the Z650. Cam chain is heavier too. I think they called these a hyvo chain or something......

no centre roller in these motors, only the cam-chain guide in the middle. Yeh these are hy-vo chains, meant to be quieter but in practice I reckon they are noiser than the old peanut-roller style.....

Eastoe - what you need to to is this - rotate the crank to 1/4 TDC as per timing marks. Make sure the exhaust cam is positioned with the timing mark exactly where it needs to be adjacent to the cam cover gasket surface. Hold the exhaust cam sprocket with a 10mm socket so it doesnt move, and rotate the crank clockwise as much as you can - which should be SFA. What you are trying to do is get the CC as tight as possible on the front run. Once you have this done then hold the crank still and rotate the inlet cam sprocket with a 10mm socket as far clockwise as you can - this is to get the rear run from crank to cam sprocket as tight as possible. The exhaust cam should not have moved at all and you should end up with all the CC slack between both cams, so the tensioner does not 'bottom-out' on a tight top-run of the cam chain.

From the pic you have, it looks to me like there is very little slack in that top run ? This will cause the issue you have. You need to get all the slack in that top run. It may need the CCT backed off/removed, depending on how tight it is. There is meant to be a lot of slack in that top run of the CC - at least 10-12mm. This gets mostly taken up when you fit the cam cover, and fitting the CCT will take care of the residual.

Have a shot at this and see how you go mate .

[Eastoe]

maybe I should just buy a commadore, lower it, get some mag wheels and a loud exhaust.
frigginfarchanbluddybastardfrigginfarchanrepeatrepeatrepeat

[steve086]

The commodore idea could work or the other option is stop playing with 4 strokes and play with tz's again

[Eastoe]

It's alright Steve, I'm just chucking a virtual tantrum.
I'll have a couple of days away from it and come back with new enthusiasm.

[Gosling1]

that's what I generally do - and its amazing when you do go back after a few days and the problem can be fixed in 10 minutes !!

[Eastoe]

Uh-oh?? Well I tried it. Got virtually no movement when trying to rotate the crank vs the exhaust cam but when I rotated the inlet cam vs the crank the chain virtually jumped a tooth on the sprocket or it felt like that anyway.
See picture for how it looks now.
Previously it looked like the chain wasn't really sitting deep into the teeth of the sprockets but now as well as having heaps of slack between the cams the chain seems to be sitting in the cam sprockets better or maybe I'm just imagining that part of it.
(thinking as I'm writing)
or was that tooth jumping feeling the cam chain adjuster pushing back in, hence all the slack.
i'd like to turn it over and check the cam timing now to see how it all looks but I think i'll wait to hear back from you Gos to see what you think.

[Eastoe]

BTW Cam cover sits on beautifull now.

[h.b.bear]

Clever boy that Gos ! I would have never in a million years thought of that being the reason but to be 100% sure I would re check the cam timing if you thought it jumped a tooth whilst you have the cover off.

[Gosling1]

that looks heaps better Eastoe. yeh that feeling would have been the CCT backing off and pushing back in. The amount of slack in that top run looks just right to me. You can re-check the cam timing now by just making sure that the timing mark on the exh. sprocket is right where it should be, the crank is bang on the TDC mark at 1/4 down at the igniter coils, and the pin-count between the exh timing mark and the inlet sprocket timing mark is correct.

If all these 3 are in spec - its good to bolt up the cam cover, finish off any other jobs - and kick her in the guts Barry

[Eastoe]

unbelieveable. I won't forget the feeling of that crack and tension release when the cam chain fell back into place.
Like being a chiropractor for motorcycles.

[Eastoe]

Fired it up for a short time this morning. Still surprisingly quiet with just a small amount of cam chain noise now.

[Gosling1]

Good to hear mate - then next thing on the list should be a balance - a good balance will help the motor run really smoothly at idle, can also help reduce other noises as well.

[Eastoe]

Strangely enough I hadn't touched the carbs untill now. Usually the first thing on an unused bike but I put fresh fuel in it when I got it and it started and sounded ok and I just didn't want to root around with that airbox but as one thing allways leads to another I removed them this morning and have ordered a radioactive rebuild kit from Japan. Surely the must have been in the fallout area as $24 to rebuild 4 carbs is way too cheap. Just like the $55 gasket set.
http://www.ebay.com.au/itm/181027062698 ... 1423.l2649
So i'll wait a week or so for them to arrive and see how that goes. I did have a real good set of suzuki carb balancers but a guy who worked with me decided he needed them more than me. I've got a set of old motion pro balancers but I think there was an issue with the mercury in one tube and i'm not up to speed with how to use them properly.
This was gunna be just a quick freshen up and do the rest later but there allways seems to be something else. At least it will save me doing it later.