Z1OwnersClub GB

Hello all
I am checking the valve shim gaps on my Zephyr 750 and noticed the the Hyvo cam chain is sitting in a raised position on the sprockets. You can see daylight in the wells of the teeth in the first photo.

I did a search of the forum and also found a photo by z1000puddin
Which has the same gaps showing on his bike with the hyvo chain (Hope you don't mind me sharing the photo)

See the link below.

There's not too much info on the Interweb, but I did find one other post on a different manufacturer forum asking the same question. To which the general answer was 'they all do that sir, its the way they are designed'

My zephyr is a complete new rebuild, with new everything. Just done 2k miles and runs fine (except for a slight rattle which I think is a loose out of spec valve gap) It has a manual tensioner.

Any thoughts from the wise? Do these chains generally sit in this slightly raised position?

Many thanks Paul


download/file.php?id=7659&mode=view

Do the gaps disappear if you apply pressure on the chain between the sprockets like the slipper plate does?
Your not comparing with the chain in the running position.

warren3200gt wrote:Do the gaps disappear if you apply pressure on the chain between the sprockets like the slipper plate does?
Your not comparing with the chain in the running position.

Hi Warren,
Thanks for your reply
No there is no change when I apply pressure to the chain.
Oddly when viewed from any other angle the chain looks normal and secure. It's only when looked at right angle that you see daylight.

Without being pedantic; Hyvo '''sprockets''' are closer to the definition of cogs than that of sprockets. The chains' contact area is spread across the face of the tooth and to qualify for the lofty title of 'Silent Chain', no parts contact that are not needed to make contact. This is partly achieved by not having the pointless extension of the chain links reach to the bottom of the root of the cogs teeth. That gives rise to the impression that the chain is riding high on the cog which it is not. If you have any doubts; look closely at the cog teeth and you will see that even when new there has never been any contact in that area throughout the life of either the chain or the cogs. You can also see that the root is effectively 'back cut' to the transmission face so it would be impossible to have contact without massive frictionional forces being a feature.
AL

Al wrote:Without being pedantic; Hyvo '''sprockets''' are closer to the definition of cogs than that of sprockets. The chains' contact area is spread across the face of the tooth and to qualify for the lofty title of 'Silent Chain', no parts contact that are not needed to make contact. This is partly achieved by not having the pointless extension of the chain links reach to the bottom of the root of the cogs teeth. That gives rise to the impression that the chain is riding high on the cog which it is not. If you have any doubts; look closely at the cog teeth and you will see that even when new there has never been any contact in that area throughout the life of either the chain or the cogs. You can also see that the root is effectively 'back cut' to the transmission face so it would be impossible to have contact without massive frictionional forces being a feature.
AL

Erm...so what your saying is that it's perfectly normal
That's brilliant Al, and makes sense. Thank you for that, much appreciated!

Paul