I did the same just now..with original belt - was left with luxorious 5mm gap between transaxle housing and motor
update Oct 2012: replaced the worn belt (at 28mm width), now the new belt makes it a bit tighter as it is sitting higher on 2nd..thus it now seems the 5mm gap should become negative..shoot! Now the AMT runs fwd and back without any gas..clutch is pulling the belt from bottom edge.
Its a 13hp Honda GX390 copy. Still need a better aircleaner.
Wow..just had a crazy idea (bulb) ! Why didnt I put the motor in the back!? You know old snowmobiles used to have the motor sitting almost in drivers lap, belt routed forward to driven pulley!? I saw some video or pic of an AMT stripped bare (no tank/battery), its a big space back there!
Pros:
+ shorter cheap belt?
+ easier exhaust line + air filter
+ easy to fix motor (lots of space) especially with these GX copy engines where cylinder leans backward
Cons:
- weight in the back
- reloc tank and battery to front (weight dist improved though)
- looong throttle cable
Motor length is 20in (500mm), from axle cc 12in(300mm) towards cylinder, 8in (200mm) to other end -> motor could sit 4in closer ==>> 8in shorter belt
..just it looks like this narrow belts are no-go in 48in length..