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Discussion Starter · #1 · (Edited)
I was doing some research on the Raptor 250 trying to figure out good gearing and tire size combos, and whether I wanted to install an aftermarket ignition system. I came across an Australian website that is in the development stage of making a fuel injection system for it. They had some dyno results for a stock 250. It looks like the highest hp is at 7350rpm, and highest tq is at 6150rp. If your optimal hp/tq is around 6750rpm and the rev limit is 10000rpm then there really is no point in revving past 8375rpm.

14/38 on 19" rear tires (stock Raptor 250)

1st gear - 18.82mph
2nd gear - 29.22mph
3rd gear - 38.79mph
4th gear - 47.61mph
5th gear - 55.45mph

15/38 gear combo on 18" tires, little better top end, doesn't sacrifice too much bottom end

1st gear - 19.10mph
2nd gear - 29.66mph
3rd gear - 39.37mph
4th gear - 48.33mph
5th gear - 56.29mph

14/37 gear combo on 18" tires, little better bottom end, doesn't sacrifice too much top end

1st gear - 18.34mph
2nd gear - 28.47mph
3rd gear - 37.79mph
4th gear - 46.39mph
5th gear - 54.03mph

With all this said, I am not buying an aftermarket ignition, and switching from a 14/37 to a 15/38 on 18" tires. Maybe if I had my head PnP and had a multi angle vavle job and stiffer valve springs I would want to be able to rev higher.

They also had a dyno for a modified Raptor 250, I am assuming "BIG 3" mods. Peak hp was at 8250 and peak tq was at 7250. If optimal hp/tq is around 7750 and the rev limit is 10000rpm then revving past 8875 is pointless. If someone were to make an aftermarket ignition that kept the 10000rpm rev limit and only improved spark timing curve it may be a good purchase. Then I could see a need for a little stronger coil as well.
 

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Discussion Starter · #3 ·
If the rev limiter on the Raptor 250 is in fact set for 10k, and if you took away rider weight, and it made good enough power to the end it is capable of doing 62-63mph stock. Based on what I see from the figures you are more likely to get 57-58mph out of it. I guess we could agree to meet in the middle and safely say they do about 60mph, give or take. Personally my Raptor 250 seems to fall on it's face in 5th, I know there is not way I am doing over 60, if I were doing 55mph I would be happy.
 

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Just because the rev limit is higher doesn't mean you have to rev it out that far.
 

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Just want to subscribe to this thread.Ported the head and put bigger valves and now its reving alot quicker through the gears so i'm gonna try 2 tooth smaller rear sprocket to take more advantage of the new found torque.Scott.
 

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Discussion Starter · #6 ·
If you put in stiffer valve springs you may be able to run a rev box as well. Might get an extra 2 or 3 miles per hour out of the top end on top of the gear reduction.
 
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