From what I recall you can buy aftermarket clutch bells-shaft and aluminum housings for Honda GX35's on Amazon. You're going to have to come up with some way to interface the Honda spec clutch shell with the little GEBE spec Gates belt pinions.
Frankly I had reservations about the GEBE's when I was looking into powering my green bike, GEBE's present clutch housings were plastic, and I had an old plastic housing from a used Gebe drive that was thrashed. I wanted an aluminum bell housing.
The wheel sheaves have issues if you're using 14 gauge spokes. Also will not work well with high flange and internal gearhubs.
Also their "racks" are just mild steel strapping and quite malleable, and a lot of times new owners have their belts shredded in less than 100 miles because the technique for fettling the belt alignment is less than ideal. Then there's a little steel strap to the seat stay bridge that has had ( in the past..) a tendency to break, causing the engine to swing backwards and pull the throttle on full. That's some pretty damning quality control issues, and it's all chronicled in this forum in the rack mount sub-forum.
There were lots of users who had issues with their kit, problems that should have been dealt with early on. I've ridden a really nicely maintained GEBE drive, it's magical and whisper quiet with a little 4 stroke, but the amount of maintenance and futzing about just drove me to making my own drive.
Why not just a decent 2 stage chain reduction? Use one of Bikeberry's 49 cc freewheeling chain drives. and a regular 410 chain sprocket on the back? that's a 75mm drum and chain reduction paired with a 10 to 44tooth sproket set for the rear wheel that's about 22:1 ratio. That's perfect for a 32 cc 2 stroke or Honda GX 4 stroke.
