by pumpguy » Mon May 30, 2022 12:11 pm
Back when I was riding a 55 Hummer, I never had a problem with a slipping shift lever. Rode this bike to and from work as well as scrambles and enduro competition.
That said, I wouldn't try a drilled through shear pin. If slipping were a problem, one thing I would try would be a round key.
Drill a small hole, say 1/8" or maybe a bit smaller along the axis of the shaft right were the clamp slot is, tap in the round key, and then tighten the clamp bolt. The drilled hole has to be partly in the shift shaft, and partly in the shift lever.
Sorry, I don't have the Hummer parts to check how feasible this idea might be.
During this same time period, we were running a 197 cc Villiers. The kick start shaft and shift lever were very soft material, and even though they were splined, sheared splines was a common problem. This round key idea was the recommended solution.