Final Drive Mystery

[kfb]

Has anyone heard of this phenomenon before?

I just purchase my 1978 gs750 and found that it had a loose chain and a slapping noise. It also rode like the back end had a wobble. I then realized that the chain was loose or tight depending on the location of the chain on the sprockets.

I checked the wheels and rear sprocket for true and the front one as much as I could see it (I can't get the cover off. I am sure that I will have to drill out the phillips heads). Everything looks aligned and nothing appears out.

I marked the chain with chalk at the two points, the point where the chain has slack and the tight point. Each time the mark comes around the chain exhibits the same looseness or tighness in the same spot.

Could this be a chain that stretched on one side? OR

The wrong chain for the bike? (not likely it appears that it has been on for awhile)

The sprockets are not worn.

If the sprockets or shaft were bent the tightness would be exhibited on the sprocket revolution not the chain location.

My last bike was a shaft drive!

What say you?

[chef1366]

Get an impact driver to get that cover off and replace the chain.
You really should replace the sprokets and chain together.

[Nessism]

Chain is junk. Z1 Enterprises is a good place and can sell you a 530 chain conversion kit for a fair price.

[kfb]

Have you heard of this type of thing before?

Thanks for the replies both of you think that it is the chain... Did it stretch on one side more than the other?

z1 enterprises shows a 630 chain will that work also, or do I need a 530?

[TheCafeKid]

It may or may not have "stretched" (god i hate that explaination for what REALLY happens) Its just flat out worn out bro...It doesnt matter how, where why or what caused it, bottom line is that at this point it is dangerous. A 630 chain is STOCK, but you dont get a whole lot of selection in those anymore...a 530 chain is just as strong, can be found in plain, oring and xring types, its lighter, which means less rotational mass for your motor to deal with, and an entire 530 conversion (thats the chain, sprockets AND the spacer for the countershaft) will cost you as much as just the chain for the 630 type. I would suggest you call Rob at Z1Enterprises and he will hook you up with what you need. BTW, it would be entirely foolhardy and a waste of money to simply replace the chain. It will last half as long as it should because generally the sprockets are what wear the chain out.

[kfb]

Thanks for the conversion info

It looks like a 530 conversion is what is needed. I will give them a call

Thanks guys!