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Stock sprockets? The gearing charts show about 10.5mph/1000rpm on 20" tires (actual diameter) for stock gearing in 5th so your #'s sound about right. That'd give the stock tires a rolling diameter somewhat less than 20".
 

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Sounds good. With peak power at 6000 rpm raptors are really undergeared even when they're stock. With the short lower gears (lots of guys use 2nd to launch even with a 15t) I wouldn't hesitate to go with a 16/36 combo, you'll still pull well past your peak power. Nice dyno #'s, btw - gonna do a cam next? Easier mod than a piston (I'd just like to see the before and after dyno charts based on the one change). I expect I'll swap in a stage 1 cam before I up the compression and port, but I'm looking forward to the power bump.
 

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Discussion Starter · #5 ·
Yes, they do have steep gears but not a steep as you would think. For instance a YFZ tops out in 5th just above 70mph and they rev way past 9000rpm. With my combo makin over 40ft lbs of torque from about 3300-6500 I can go real tall on the gears if I wanted to:
 

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Yah, that's what I'm saying: Yamaha geared it short, esp. in the lower gears, which makes it easier and very effective to go taller since first will still be plenty low enough and you can run well past the power peak in fifth. :thumbsup: Why rev the nuts off it when all the power is below 7k - I love the power curve on this thing!
 
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