RB 220 Mods RPM Range

Questions and Answers about the best carb and Head mods available for the KDX.
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UtahNorwegianPhil
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RB 220 Mods RPM Range

Post by UtahNorwegianPhil »

I just rebuilt my daughter's 2005 KDX 220. Includes new cylinder coating (Millennium), Wisco piston, Boyesen carbon reeds, FMF woods pipe (bought this first, before I read that the desert was probably better) and silencer, and RB head and carb mods.

I am installing a Trail Tech Vapor. Everything works except the rpm that I need to reset the pulse from x1 to x2. That got me wondering what the normal rpm ranges would be. The Vapor has set points for "shift" and "Over Rev". The question is what would idle, shift, red line, and max power rpm's be with these mods? I know that shifting really depends on the situation and terrain, but a generic shifting point would be nice. I can probably come up with an rpm for shifting after riding for an hour, but I would like someone else's opinion. Who really cares about rpm, temp, or speed - only if you have a computer, I really just wanted an hour meter for maintenance ....

Also does anyone have a guess on the peak HP with these mods?

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cornishwrecker220
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RB 220 Mods RPM Range

Post by cornishwrecker220 »

I can't help with the vapor trail tech but on HP of the 220 my bike ( before I had it ported & set up ) had a FMF woods, boyesen rad valve, modded air box , 35mm kdx 200 carb.... Bike ran very well but on the dyno surprising only pushed out around 26 odd Bhp at the rear wheel ! ( Kawasaki claimed 37? )
My bike had a full engine rebuild using quality parts , head modded, cylinder ports measured ,matched & opened up with power valves suited..piston was also modded....a 36mm carb from a 1990 kx 125 was installed & jetted according using the dyno, the timing was altered & raised.....the dyno print out was a very healthy 39 Bhp at the rear wheel & well over 40 at the crank, with a good increase in torque throughout the whole Rev range & no loss in bottom end pull.
At a guess I would estimate that with your mods your daughters bike would be running around the 28-32 Bhp mark .
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C George
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Re: RB 220 Mods RPM Range

Post by C George »

Let me know how the TT Vapor works for you . I have one on my sons bike and Tried everything and still can get the rpms to read accurately.

I've used them on other bikes and worked great. Their tech line wasn't very impressive.

I'd believe 30-35 hp on your modded 220 engine , I really like the power curve compared to the 200.
05 KDX-220R / 06 KDX-225R / Maxima 927 / Millenium Tech / Ron Black / PC , FMF / Many 220 engine mods / 40 + yrs. of riding dirt bikes 🤟🤟
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