A couple year's ago, I tried to do what you're doing now. I got some sprockets from an online site. When I drilled them to accept a .5" BMP driveshaft, there wasn't enough meat to notch the keyway. So I gave up the project in favor of a center/mount shift kit assembly.
Come to think of it, I shoulda welded the sprocket directly to the BMP shaft. Shafts and sprockets weren't that expensive, so I coulda made a couple with different gear sizes.
I forget where I got the sprockets, but you can google here or on the other website.
Throw out that question regarding GEBE size. Someone's bound to answer.
I asked that same question, so it's prolly in that same thread of mine.
I'm not sure what size to get or from what type of other application. The gebe one won't work without modification to both spindle and sprocket. I am thinking that a piece of belt epoxied to the spindle could work. If it does then the pinion will be about 7/8" maybe larger. When I flipped the mount the turnbuckles aren't long enough now and the one one the belt side had to go cause the belt was touching it. so i need a longer better quality turnbuckle on the engine side and that should be sufficient I hope, the only other option is to use some clamps on the frame down tubes to attach some strut straps similar to the axle mounted ones.
