Well me and a buddy put a yamaha warrior front and rear suspension in a 96 formula three frame. We put a honda 750 bike engine in it, and its not done yet but heres the question: we need to know what gearing to use? there will be a chain from the engine to the axle (the first axle which is located where the stock sled axle was) Then there will be a chain from the axle to the actual atv axle! Honestly I dont even know what gears to start with! I kind of thought two gears that are the same from engine to first axle but no idea what size. assuming smaller! But any help would be appreciated. Thanks

you have to figure out your gear ratio you want and start plugging in # until you can figure it out

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ATV SAFETY INSTRUCTOR
91 WARRIOR
2004 Z400
325 TRAIL BOSS
250 TRAILBLAZER
2004 LTZ 250

25 years in the Army Reserves
1 tour in Iraq ,serving proudly

I'd start by reviewing what the bike had for sprockets. From there look at the difference between the tire height of the bike vs what you will be using now. You probably aren't going to need the speed the street bike had, so a shorter tire than the bike will get you a lower ratio and closer to what you might need.

I think you can get close using the stock bike sprockets on the engine and your jack shaft, then using the same toothed sprockets on your jackshaft to rear axle if your tires are shorter. Keeping the sprockets the same on the jackshaft to rear axle the same would simplify changing the ratio later. You'd only have to change one sprocket. The engine sprocket is the cheapest to replace.

Of course there is a method to take all the guess work out, but that involves a little bit of math....

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tread lightly

Thank you very much!!! that will help alot! That oes make sense, and your right Im not looking for extreme speed, just something to toy with! Thanks again!!!

Do you have any pictures of this creation??? This sounds interesting!

Yea.. Pictures...

Ski-Hon-Maha? or Yama-Doo-onda ? Hon-Doo-Aha?

LOL

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CraZy Steve
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2007 Grizzly 450 4x4
- Warn 2.5ci Winch w/20 foot remote
- GYTR Deluxe Rear Rack Extention
- GYTR Skids (Belly, Rear, Front A-Arm)
- CSS (CraZySteve Skids) Footwell Rock-rails
- CSS Front CV Boot Extenders (attached to GYTR A-Arm Skids)
- Garmin GPSMap 60Cx w/R.A.M. Mount W/Topo 2008 USA Maps
- Snorkle for front of Belt Drive

Sounds like a cool project! Pics would be great!!

The sprocket gearing math isnt all that tough. Including the wheel dia does get tough. With the sprockets think of it like this...say you got a 15 tooth on the front and a 45 on the rear.(between the engine and the jackshaft) 45 divided by 15 is 3. That gets you a 3 to 1 ratio. If you do the same thing between the jackshaft and the rear wheel you get another 3 to 1 ratio. But you now need to add them up. You have actually got a 6 to 1 ratio from the engine to the rear wheel..

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07 Jetmoto 250 Sport
07 90cc Mini Ute
06 Jetmoto 200 Enduro
06 Jetmoto 200
06 Jetmoto 150
06 Jetmoto 125
04 Yamoto 150
01 KTM 400 EXC
92 WR 250
91 CR 250
88 YZ 80
85 CR 500
83 XL 600
82 XR 200
79 XR 75
79 Odyssey
73 Bultaco 360
71 Rickman Montessa 250
70 Rupp Enduro
69 Honda 50

Edited: 05/07/2008 at 09:28 AM by mywifesquad