gsxrscooter

I am currently rebuilding 2 sportmaster drives (RH & LH)and wondered what gears determine the final drive ratio. Do the prop shaft gears remain the same and the crown gear on the drive shaft change? If so does the spacing between the prop shaft gears have to change? I have 1.75:1 drives and I am considering going to the 1.62:1 ratios for slightly more top end. I'm just touching the rev limiters now so I could carry a little more ratio. I am relatively new to these drive units, any help would be appreciated.

Thanks,

Scott

ziemer

I believe you would need to switch out the full gearset.

When I replaced mine about a year or so ago, I ordered a new gearset and they sent me the pinion gear, forward, and reverse gear as a set.

Get your wallet out, because list price is around $850+ per set.

gsxrscooter

Thanks, I was afraid of that, I have 3 sets of gears now, 2 @ 1.75:1 and 1 @ 1.62:1 so worst case I will only have to buy one more. I,m also making up my own gear case vents with a vented, remote reservoir under the cowl, maybe I'll gain a little life out of the gear sets. Have you heard of this being done on outboards before?

John the Drive Man

It is the combination of both the upper and lower gears that determines the overall ratio. On the Sportdrives there are 3 different ratios for the lower. Depending on the ratio you are looking for, you may be able to get it by changing only the lower gears. But sometimes you have to do both. It depends on what you are after.

gsxrscooter

Thanks John

Hopefully a week away from seeing the lake.