750 cam chain.

Alright, I just bought a minty GPZ750 (84) with 41,000km's on the clock. The bike has been very babied and has an awesome maintinence record and most of the km's on it are highway. BUT, i notice at lower RPM, like when it is warming up when it's idling a bit rough, it has some camchain noise, and even after it's warm, but not as bad due to the idle smoothing out. Now what are the chances of a worn out chain on this thing? I don't figure a ton of wear due to oil changes every 2000km's older lady owned and used for touring more or less...It still has the original tensioner on it, is there a way to see if you can take up slack??

OH and i do have a haynes manual, but it sucks.

Post edited by: tnutz, at: 2007/02/07 16:27

im guessing that new of a bike has an auto tensioner on it,so im not sure how much you can adjust it.maybe measure the links to check for wear,id reccomend a factory shop manual if you can get one they are a lot more detailed;)

alright, well. It had the valves done last year, so maybe i will wait till the next adjustment to get er done. It's not horrendous or anything. But of course i notice it.

I can't see it being worn enough with the km's it has, manual tensioner maybe???? heard the automatic ones suck

If it looks like this then its manual and can be adjusted .
Chances are though that on an 84 you have one of the newer "automatic" tensioners.
Wonder if what you are hearing is primary chain chatter which on mine and is evident at idle. I hear others saying the same.

Alternative would be to use one of these.

Primary chain eh? learn me!!! i have no clue what chain that is? It is definetly an automatic.

Post edited by: tnutz, at: 2007/02/07 21:54

well i just read some stuff when i searched and it said alot of primary chains seem to make some noise, and I know what cam chain sounds like (thanks to an 86 GS550ef suzuki i have with about a bajillion km's on it) and this does not sound like that at all.

The suz i have with a hyvo thats worn bad sounds like a can of marbles, this is like a lower type of sound that is lower down in the engine, and goes away with higher rpm, and when the engine warms up.

Post edited by: tnutz, at: 2007/02/07 22:18

Classic symptoms of a worn primary chain.

I have been told (and research seems to support it) that 81-83 Honda CB900C primary chains are the same size as the KZ/GPz750 primary chains, and a whole lot cheaper.

I'm not losing any sleep over my primary chain just yet. It chatters a bit at idle and goes away when I'm running... and I have about 57,000km on it
Best way to find out where exactly the noise is coming from is to use a mechanics stethoscope (?) or or an improvised one. I use a big screwdriver, put the handle to my ear and the tip to various points on the motor. A 1 inch wood dowel or similar will also work. That should help pin it down. If it seems to be coming from the crankcase then it more likely primary chain.

Good luck

it's def. down low. I know what worn cam chain sounds like and this isn't it. But now that i know what it is i'm not losing sleep over it either.

Just a thought but are your carbs synched? If your carbs are not synched the primary chain will rattle at idle. Depending on how far off the carbs are the rattle can get very loud.