Dumb question - good answer? [?]

[Klaus]

I've always wondered what these black little rubber pucks are supposed to be good for on new air cooled engines? They sit between the fins, I'm sure everybody has seen them at some time, and sooner or later they disappear, fall out. What's their purpose, I wonder?

 

[BobS]

Klaus

In the 1970's, I had a BMW bike in the US. BMW sold those little rubber pieces as an accessory to reduce engine vibration and noise. You installed them in between the fins on the cylinders.

BobS

 

[Klaus]

Hi Bob, I thought about vibrations, but especially BMW would come up with a better idea? Usually those things disappear after a few thousand miles, and I haven't noticed a difference. Just sold a Kawasaki Boss 175 and the guy asked me what those rubber things were for, I didn't know what to say. Vibration and engine noise on a 175cc engine? There's got to be another explanation!