You know, 2M has a point and he knows these engines better than anyone here I think .... perhaps a rubber hose mounting of the carb and have the carb base bolted to the frame ?
I've seen vibrations turn carbs into junk before.... My brother in laws 305 scrambler back in the day was so heavy in the vibration department
that it broke the frame destroyed the carb floats several times ( they were brass luckily so we resoldered them) , it got to the point that the emulsifier tubes would fall out ..... the main jets would wind up in the bottom of the float bowl and we'ed have to fix it on the highway, and in general made it Hurt to ride,.... the Buzz put your butt to sleep in a few miles,..... but it had twice the HP my 305 dream had ! LOL
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Bob.......