Need little help choosing best gear set for my dio spree.

[akurtzer57]

Got the dio swap done in my spree and before I do my big bore etc going do some basic stuff going with a keli variator, new polini belt and a gear set. I was thinking 9:1 but have no idea whats best for top end whats low end etc. Looking for top speed 55 or so when my build is fully done. Any help appreciated. Also very confused when there listed as 15x42 16x42 etc What is what here?

[Wheelman-111]

Greetings:

9:1 gives OK take-off and a top speed of 55-60, more depending on the max RPM of your setup. With its stock carb and muffler, Flash 9 seldom revs above 9000 and will hit 55.
Final drive ratio is easy to calculate if you keep in mind the two sets of gears that mesh together.
A. The clutch shaft.
B. The bigger gear on the countershaft.
---------------------------------------------
C. The smaller gear on the countershaft.
D. The big axle shaft gear - Hard Press fit.

So it's B/A multiplied by D/C.

See Aftermarket Tooth Tally and Mousewheels' helpful tables to see that 16/42 secondaries yield 9.1:1 Final Drive.

[bonesv]

I have this list I use for reference but it may not be exact.

15*42 = 9.8 to 1
16*42 = 9.1 to 1
16*41 = 8.96 to 1
18*41 = 7.97 to 1
17*41 = 8.44 to 1
18*39 = 7.5 to 1 ???
19*38 = 7 to 1 ???
19*37 = 6.8 to 1
Then there is this chart which will help you

gear ratio to rpm for top speed graph.jpg (155.76 KiB) Viewed 8749 times

[akurtzer57]

Looks like 9.1 will be my choice. I tore apart inspect make sure it didn't have a variator already. Didn't think it did tops out at 30mph but hey never know. Rollers pretty worn and flat spots. Im not sure if this is stock or not any ideas?

[bonesv]

It's stock.

[MrJumps]

Okay technically speaking here could you mix gears from difrent sets around like the stock seperate singal gear that dosnt require an press could be swapped with a 9:1 setup but the stock gear on the shaft stays the same. Will the gears mesh or if they dont would it still be a change in gearing that would effect you?

I know this may be an weird question but when your younger and on a super budget you try to find the cheapest way to do things.

[Wheelman-111]

Greetings:

NO!! You must swap gears as a set. Otherwise the circles won't overlap, 0oOor they overlap too much dig? If you can be sans scooter for a few days and pay postage, there are several Forumistas who own presses who will step up to press your new gear onto the shaft for you.