Does anyone know how much length we gain if we add only the Kawasaki rear pulley?  The reason I ask is because I was looking at the voodoo vintage custom hard tail and wondering if I could make up the extra 4" of length with the smaller Kawi rear pulley.  Even if I had to make some adaptations to bring it a bit closer.  I switched from the pulley to the chain and sprockets several years ago and could never figure out why I went through a chain every thousand miles.  So switched back to the belt and stayed off the freeway.

The Kawasaki KZ750 pulley is 3 teeth smaller.....I will go out an measure the difference - but the extra length is likely going to be an inch or less.

There is another Kawasaki pulley that has a lot less teeth and might get you a lot more change....I can't remember what model it is.

I also believe some of the Kawasaki belts could be longer.

I believe the KZ440 used 2 different size pulleys:

This one is the big one (same 65 tooth as the KZ750 but fewer mounting holes).
https://www.ebay.com/itm/1983-80-83-KAWASAKI-KZ-440-KZ440-LTD-BELT-REAR-PULLE...

This one is smaller - but I don't know how many teeth (and it could also be narrower).

https://www.ebay.com/itm/KAWASAKI-KZ440-LTD-REAR-PULLEY-Belt-DRIVE-SPROCKET-H...

One version of the KZ440 belt is 129 tooth.
https://www.ebay.com/itm/GENUINE-Kawasaki-KZ-440-Final-Drive-Belt-Pulley-129-...

The Vulcan 500 also uses the same type Bando belt.....not sure of the length of that belt or the KZ750 belt.

There is a lot to look at and explore.