crank-mounted starter sprocket

[Dick Eastman]

I went through my stock of sprockets, rotors/parts, and found two that were within specs/good shape to re-bush with hard bronze. One was from the Dream parts engine [s/n 10098xx], the other a SuperHawk [104xxxx]. It appears Honda made a thickness change, as the Dream sprocket does not have a step. The inside face of the rotor ass'y is .565" to the bottom; the stepped sprocket is .545" from the nose of the sprocket to the stepped face, which means the sprocket face will contact the rotor face, with .020" to spare. The Dream sprocket is .575" from nose to face, i.e., the nose of the sprocket will bottom out in the rotor before the two faces contact, with .010" to spare. See the photos.
My Q is: Does any part of the sprocket [face or nose] make contact with the rotor, besides the rollers? I realize the sprocket "floats" on the crankshaft to center itself with the starter motor sprocket via the chain.
The last pic shows the step [rt sprocket], and on the crank in third pic; the second pic is the Dream sprocket on the crank, showing space [.010"] between two faces.

[LOUD MOUSE]

<<<I realize the sprocket "floats" on the crankshaft to center itself with the starter motor sprocket via the chain. >>>

There is a part "starting sprocket stopper" which won't allow the sprocket to move away from the engine toward the "starting clutch outer" and if you install the sprocket without taping the center into the crank seal that "stopper" may seize the sprocket and not allow you to turn it by hand. .................lm

I went through my stock of sprockets, rotors/parts, and found two that were within specs/good shape to re-bush with hard bronze. One was from the Dream parts engine [s/n 10098xx], the other a SuperHawk [104xxxx]. It appears Honda made a thickness change, as the Dream sprocket does not have a step. The inside face of the rotor ass'y is .565" to the bottom; the stepped sprocket is .545" from the nose of the sprocket to the stepped face, which means the sprocket face will contact the rotor face, with .020" to spare. The Dream sprocket is .575" from nose to face, i.e., the nose of the sprocket will bottom out in the rotor before the two faces contact, with .010" to spare. See the photos.
My Q is: Does any part of the sprocket [face or nose] make contact with the rotor, besides the rollers? I realize the sprocket "floats" on the crankshaft to center itself with the starter motor sprocket via the chain.
The last pic shows the step [rt sprocket], and on the crank in third pic; the second pic is the Dream sprocket on the crank, showing space [.010"] between two faces.

[Dick Eastman]

<<<I realize the sprocket "floats" on the crankshaft to center itself with the starter motor sprocket via the chain. >>>

There is a part "starting sprocket stopper" which won't allow the sprocket to move away from the engine toward the "starting clutch outer" and if you install the sprocket without taping the center into the crank seal that "stopper" may seize the sprocket and not allow you to turn it by hand. .................lm

Thanks, Ed
I had forgotten about the stopper. I did notice some of the sprockets on hand had some heavy wear marks on them where the stopper rides, as well as excessive wear on the bushings on those - also appeared that the chain was predominantly rubbing one side of the sprocket teeth. This combination of wear indicates that the two sprockets were not in line, and the lateral force of the stopper/chain prematurely wore out the sprocket bushing. I think a better stop for the sprocket on the crankshaft would be to make two thrust washers - one between the sprocket and bearing shoulder, the other between the sprocket and "starting clutch outer" - this only after starter motor installed for alignment between the two sprockets. This would help with the life of the crank sprocket bushing. Honda had to mass produce their design within manufacturing tolerances, and probably some sprockets had more side force from the stopper than others, the bushing took the brunt of the lateral force. I'll continue this once I get to that point in assembly.