how fast will it go

[jacksmurray]

hey guys im gettin me an old craftsman 11hp an im wondering how fast it will go with my 12 or 12.5 hp murray(b&s) motor with stock pulley and i believe a spicer, 4 speed with a 2 inch pulley

 

[KennyV]

Here is an Easy Pulley and Speed Calculator: Pulley and RPM Calculator | Engineering Information - Culver Armature and Motor
Scroll down on that page and put Your numbers in... It will tell you the RPM changes you will make with any change.

Remember that as you go smaller on the input on the transmission you also reduce the belt contact area on the pulley... so you will reach a point that no matter what the belt will only Slip, netting you zero speed.... :smile:KennyV