The gear that drives the chain on the gearbox side rides on a 1" shaft.
Last season I seemed to be shearing the shear bolts off for no apparent reason (not often but just more than normal with no obstructions) last season so I pulled the gear off the shaft.
It rides on a 1" shaft and the gear is 1" diameter on one end and 1 1/8" on the other. Guess that would provide some reason.
Unfortunately, there is no bushing and no doubt that gear and bracket assembly would be pricey so I'm going to get my buddy who's a machinist to drill out the gear and make a bushing for it.
Might even get him to make me a spare if he has time.
Hopefully this solves the shear pin problem.