TOPIC:

steell wrote:

I have measured five 750 four primary chains in a search for a good one to install in my GPz750, and every one of them was at or beyond the specified service limits.

I think every GPZ motor out there is like that. I hear that primary chain slapping in every 550 gpz I seen. ...too many clutch-poppin squids, I suppose...

How much longer before they start breaking, I wonder?

Post edited by: loudhvx, at: 2006/10/14 21:12

They never break. You could have a primary chain that's stretched to 8ft long and all it's going to do is make more noise than one only stretched to 7ft.

Alrighty then! I'll replace mine when it stretches to 7 feet... to cut down on the noise, that is.

There are two primary failure modes with a link-chain drive. The first is a progressive failure which results from an apparent elongation of the chain due to wear in the link-pin joint. Failure occurs when the apparent chain elongation has reached the point that the chain begins to skip teeth. Catastrophic failure is not far behind that event.

www.epi-eng.com/GBX-ChainDrv.htm

Important Rebuilding Notes
Chain Elongation: Even though Morse Hy-Vo Products are built to last, when the rebuilder has
the unit down, the sprockets and chain should be checked thoroughly.
Remember that it is very difficult for the aftermarket customer to measure chain elongation. One
reason for this is shaft movement when the unit is apart. In certain cases, when the shafts are
fixed with the cover off, an experienced field estimate may be acceptable.
Morse has special equipment to measure elongation parameters. In addition, each application
could be different depending upon the application parameters.
The accuracy rate or error rate is 50% without using the right equipment to measure elongation
of a chain. Every application has its own variations and the manufacturer’s recommended
specifications for chain tolerances should be referenced.
If the chain has been in service for over 60,000 miles,
if the unit is torn down, or if the unit shows
signs of problems, neglect, or abuse – replace the chain.

www.rsgear.com/borgwarnercat.pdf

Post edited by: steell, at: 2006/10/14 22:35

Steve, just a follow up on Bo's excellent tip about the Honda chain. MrCycles have it listed for $102.58

www.mrcycles.com/fiche_select.asp?mfg=Ho...number=13610-438-004

Post edited by: ibsen22000, at: 2006/10/15 07:39

Steve, not to open a can of worms, but what are your thoughts on changing the sprockets for that chain? Is it even do-able? I know conventional chain-wisdom usually says to change a worn chain along with the sprockets, but ...?

Isnt the front sprocket part of the crank the same as the cam sprocket?

That's what I'm assuming, in that case new crank? Yikes. Good thing I'm stockpiling 550 botom ends in the basement. Oh, and Steve, I may have a 550 trans for ya by spring if all goes to plan.

Post edited by: loudhvx, at: 2006/10/15 13:41

The more 550 trans the merrier, I have a couple of GPz750 motors

The HyVo chain is totally different than the roller chain and I don't think the sprockets wear very much. It's kind of neat the way they work.

Weld those two gears together and it will never make noise again.