Mike is it safe to assume you want the fat tire? My brother did this with a complete custom frame he made it was sick he sold the roller before he finished it I think he bought the hub from eBay with the axle and bearings. Ill check I think I have a tire or two I can hook you up with
On the Onan motor do the pistons go horizontal ? If the 8 hp motor is a Honda the best thing to do is buy a new crank and thats $155 and comes with a new bearing installed...I have a blast in the pitts at Milan at noet......i`m up 3 hotdogs and a cheeseburger..lol