Been wrenching soooo much....no posty...best I've found for a 103....Gates 5VX350. It sits lower into the cheek than a BX...even though it's 3mm taller....because maybe the 2 degree difference on the taper of the belt.. I dunno...but it does. And...the teeth of the belt actually touch the hub! What? Yeah.
It's a stiffer belt.. more like a kevlar. Running this with a doppler clutch pulley.
Starting. ...well....if you have decompression it's 100% gonna hook up. For my no decompression malossi 70...still no problem...it will almost turn over just pushing....but what works for me it's to give it a push and get a foot to the lunch lever...boom.. yeah...you have one right? Game changer.