#1 Use a skate board wheel on the lower chain run to keep the drive chain from dragging on the frame casting.
#2 Use a 1/1/2″ belt drive for a late 30’s Knucklehead… And trim 1/4″ from the belt width… Use aviation tin snips.
#3 You may need to open the frame slot for the trans lug a wee bit… Use a hand file.
#4 If you are retaining a tank shifter.. Take the steps out of the shift lever guide… Flip the ratchet shifter lever upside
down.. Make a custom shift link from 1/4″ rod with ball swivel ends.
*You can run up to a 26t trans sprocket, depending on what your engine can pull…
Other approaches to this upgrade will work… This one is pretty easy and requires only hand tools and a few bits from the hardware store… We’ll post pictures in a bit.
- You may want to add a stiffing plate under the trans/frame lug… That will allow support for the 5th mounting bolt, closest to the kicker side… This will eliminate the trans from eventually cracking from the kick starting forces.