Re: Need a motor adapter for an 09 Electra coaster 1crusier
I have a motorized Electra Coaster 7D and I mounted my motor by attaching the front to the down tube as usual (this avoids muffler clearance issues) and fabricating a simple rear mount using bar stock and some U-Clamps. The major issue with this frame is that the extension needs to be so long that you need both horizontal AND vertical support. The photo (I know, it's not very good) shows what the completed mount looks like. Note you may need to extend your chain for this to work.
The steps I took are basically...
1) have someone hold the motor to the frame so you can make a cardboard template of your mount.
2) Bend bar stock to fit leaving a tab on the bottom and back to run your U-clamps through
3) Drill holes for the motor mount and the U-clamps. The bar stock I used was just barely wider than the frame and matched the motor mount width pretty closely so the U-clamp holes were really notches in the mount.
4) Bolt the mount to the motor (paint it first if you wish) and install.
Since the Coasters use aluminum frames I cut copper tubes that matched the bike tube diameters in half and used the half on the curved part of the u-clamps (between them and the frame) to provide some additional support and spread the load out.
I'm sure a reverse of this idea would allow you to mount the back of the motor to the seat tube, but then you'd have trouble getting the exhaust to fit.