National sidecar - clamp inadequate- anobody with the same issue and fix?

[Nils_r]

Hi- I have a National sidecar attached to my 16J- it includes the vibrasorb connection for the below the seat attached bar (which is connected to the sidecar frame via the vibrasorb). Problem is that the vibrasorb unit it will move during driving - sliding on the frame tube- ie rotating- making the bike go from leaning out to leaning in. Wondering if there are some parts missing or if the clamps were inadequate on these cars- any fixes or advice? I could of course weld a mount to the sidecar frame but painful to do as it is all painted and shining. I have the feeling I have seen national sidecars being attached with a more straightforward clamp as well.
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