What size belt fits a 31 tooth front pulley and a 61 tooth rear final drive ? It's a 88 softail but it's been rebuilt with a mixture of parts all HD ..

 

i ran a 128 tooth ( stock belt for 93 softail) with a 32 front and a 61 rear on a 92 softail. they make a 127 tooth also. i did have to buy 93 softail axle adjuster bolts. they are a little longer..