Cam chain tensioner query

[clive1]

Hi All, I am new poster here but have followed this forum for a long time now and have found it very very helpfull, i am building a Z1000A1 1977 model and have the engine stripped down now for cleaning and polishing, my question for now is this, the camchain tensioner wheels/cogs have a black ring around them each side i suppose its to dampen the chain noise, is this ring meant to be rubber as mine is rock hard i'm asking this because all the rubber dampers 6 of them have also gone very hard and i know they are rubber originally, so i'm wondering if i need to replace these items there are 2 cogs and the top centre cog which is caged,
any help here would be much apriciated.
cheers,
clive.

[Pigford]

As you've got thing in bitz - it'd be best to change the wheel as the hardened rubber could break up and thats not exactly desirable

[clive1]

thanks for the reply pigford, thats what i was thinking, i justwondered if they set off life as soft rubber or where allways like a hard material.
cheers again
clive

[z1bman]

you can get them from debben performance but not cheap

http://www.debben.co.uk/acatalog/Z900.html

[zed1015]

thanks for the reply pigford, thats what i was thinking, i justwondered if they set off life as soft rubber or where allways like a hard material.
cheers again
clive

They were originally soft rubber and designed to dampen camchain noise by allowing the chains side plates to cushion against them.
They go hard after many heat cycles and eventually break up which presents itself as black silt in the sump.
The sprockets will happily run with the rubber removed with hardly any or no audible difference.
Most after market or performance replacements (Liska etc) are undamped solid steel items. See Debbens web site for prices.
Your original sprockets can be modified/reclaimed with billet centers and a new bearing if the teeth are still good.