Forums
Some timeago I put Mk3 isolastic conversionson my Mk1 850. The bike seems to have more vibration at low revs than with the original type.
Is this because the Mk3 types have both buffers and main rubbers moulded out of the same type of rubber? Looking at the original type of isolastic, it seems the main rubbers are softer than the buffers.
I amgoing to rebuild the isolastics this winter and am leaning towards putting the original type back in with Mick Hemmings type adjusters.
It would be nice to hear some thoughts on this.
Paul
Paul Could be because the…
- Log in to post comments
Paul
Could be because the original main rubbers have been hammered over the years or someone replaced with later/different parts. The buffers only come into play occasionally. If they were in regular contact vibration would be severe. I know that from a bent frame and one buffer being in continuous slight contact (severe angle on main bolt). It's commonly known that the rubber compounds did get harder over the years and one US guy has done comparative tests. There is talk of soft rubbers available but I don't know what that means compared to 1970'ish originals. I have Norvil 'vernier' kit in mine and they are quite soft but I didn't keep the original Andover std replacements previously used to compare. What I do notice even with 10-12 thou clearance front and rear there is higher frequency vibration at 4k+. It's not bad but I don't have the 'turbine' smoothness many Commando owners talk about. All my ISO tubes have been squared and the offset front and rear made the same to correct weave and to help with even clearances around the end caps.