19" front rim (cb750) laced to a rear drum

[gribbs]

This is possible right? Everything should mate up kosher, no? Anything pressing I need to keep in mind?

Better yet, could I some how attach the rear sprocket to an existing front 19" wheel, and use the stock disc brake as well as to have a rear disk brake setup?? That would be pretty rad

 

[Fishhead]

I tried to use an 18 inch rim that was for a small (disc brake) hub on the rear of a drum brake CB 750.

The spokes were on a bind at where the spoke and nipples meet and would have been the weak link in the lacing and prone to break. The angle of the spoke holes are drilled different depending on what hub (size AND width) it is made for. They could possibly have been redrilled for the smaller hub.

I ended up lacing the same 18 inch rim to a front hub and converting it to rear use. I made an aluminum sprocket adaptor and changed the bearings to 20mm and changed the brake to disc.

The sprocket adaptor has an extra bearing added in the hole in the end.

I ended up going with a twin piston underslung caliper.

Anything is possible, but it would be easiest to get a rim that has the correct drilling in it (angles) for the larger drum brake hub.
I chose to do it "my way" to specifically change the rear to a disc brake.
The Yamaha XS 650 guy "Omar" sells a kit to convert a front wheel to rear use (XS 650).