Re: Electra Straight 8 3i
I own an earlier version of the straight 8, back when they used the chopper style forks on it, but I am sure the pertinant mechanics haven't changed. There are two major obstacles to mounting on of these kits on the straight 8. The first is the extra fat tires. The motor would need to be offset to the side in order for the chain to clear. The second obstacle is that the hub where the drive gear would need to connect is extra large so the large center whole in the drive gear would need to be made even larger.
BOTH of these obstacles could be overcome by using a shift kit and simply driving the bike through the regular chain (and give you three speeds to boot). In short, any solution will cost extra money.
This is on top of finding a way to get the engine to sit inside a "non-vee" shaped frame.
Once I identified these issues I gave up on the idea. In the end I built my first motorbicycle on a Electra Coaster 7D frame and it's still my main rider today, four years and four other builds later. Doesn't stop me from looking at the straight 8 or Rally Sport (another older fat tire Electra Cruiser) I own and wishing. The Rally Sport has the additional problem of a frame piece right where the motor would need to go.
If you do this, please please PLEASE post photos.