Are R69S rubbers still a problem?

[Allan Atherton]

I had an R69S in the 1970's and again in the 1980's. When I owned the first bike, the rubber sleeves in the vibration damper would last about a thousand miles. When I owned the second bike, some rubbers lasted only a few hundred miles. It was a constant problem, so that I would never want an R69S again. Are good rubbers with a long life available now?

[Mark Huggett]

Hi Allan.
You've touched a sensitive point here.... the rubber bearing on the vibration damper is still a sore point today. We sell many rubber bearings with differing results. Some last 2000 kms, others seem to last forever, or maybe people just don't ride any more. Many of the long distance riders as well as all the racing guys simply remove the complete vibration damper unit.

Best regards,

Mark
Mark Huggett GmbH

[J. Stracco]

If I understand correctly, the vibration damper acts like a mini flywheel, absorbing
crankshaft vibrations. The rubber sits in the middle of a steel disk and is sandwiched
two "plastic" washers. A connecting bolt runs throught the center which attaches it to
the Generator mount.

Has anyone manufactured a SOLID flywheel, of apporximately the same dimensions and
weight? It could be steel, aluminum, or hardened rubber, but being that the whole
assembly is one piece, it wouldn't wear out and come apart like the stock assembly.

Could another solution be simply to add more weight to the clutch flyweel?

[Allan Atherton]

The damper is not a flywheel. It does not store rotating energy. It is a mass that buffers the bending of the crankshaft. The crankshaft does not have a center bearing. The power of the R69S is able to bend the crankshaft at high RPM. The bending is accomodated by the special spherical bearings, but needs to be dampened. The resilient rubber insert of the damper absorbs the movement of the front end of the crankshaft, and gives it back when the max flex has passed, dampening the effect.