I had to remove engine, jack shafts, and gas tank from frame to modify both left and right side of rear stays on frame.
I cut and welded notched out sections to accommodate the sheave for belt drive and the knobby tires.
For more than safety I am designing more complete covers over the dual jack shafts that have pulleys, belts, sprockets, and a chain. This is since I removed the stuff temporarily to not get damage from near by welding I was doing on the frame, I saw how grimy the chain and sprocket had gotten.
I sort of wondered if complete covers over chain have been done before. I know the new thing is shaft drive and then it is all concealed.
Belts don't need lubrication and do not get that much grime, but small pulley less than 2 inch diameter sucks trying to not slip with 21:1 ratio 3hp 4stroke Briggs trail bike. That is where a short section of chain between two sprockets I use chain lube.