Two Stroke Motocross
Two Stroke Motocross Forum => Technical => Topic started by: BC221 on January 11, 2010, 12:46:39 PM
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I have an '09 YZ250 (stock) and was thinking of adding a Rad Valve (or Moto Tassinari) to beef up the mid range. Does anyone have any experience with these devices and what should I expect when installing one? Do I need to re-jet?
Also thinking of adding a Pro Circuit or FMF pipe to add a couple HP. Again, if anyone has experience with one of these, I'd appreciate some feedback with respect to jetting or what power characteristics I can expect.
Anyone have both a Rad Valve and pipe installed together?
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I've used both the RAD valve and V-Force reed valves. The RAD valve will provide a flatter power curve. The V-Force will usually put a pretty good hit in the power curve. As for actual HP increases, they both provide about the same HP gains. The difference is in the power curve. Pick your pipe accordingly. Jetting is done on each bike individually. You probably won't be using the exact same tune up any one else does, even with identical parts. Sorry MXA "wrecking crew", it's not a one size fits all proposition.
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I have a Rad Valve in my 2000 CR250 and it made a big
difference. No more snap crackle and pop runs a lot smoother.
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I used the Vforce on my 08. I didn't notice a difference but I put on my Oring chain at the same time so I guess the evened each other out. I tried a Pro Circuit pipe and got more power but traction went way down. I went back to the stock pipe since power is strong but manageable and I can always feather the clutch for power. Its more fun to ride that way as well. FYI bleed the air from your forks every ride (not every ride day, every ride) since they build up a lot of pressure quickly.
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With the PC a little fly wheel weight may have helped the traction problem. Or a change of air pressure.
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You also might try a "Power Now" They do help at equal to or less than half throttle.
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With the PC a little fly wheel weight may have helped the traction problem. Or a change of air pressure.
Flywheel weight for sure, i fitted one to my CR and it made a big difference.
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if your clutch has aluminum drive plates you can replace them with steel. gives the same effect and it's cheaper than a flywheel weight. i used to do this with CR500's and KX500's. they didn't stall as easily in corners and when kicking over the extra mass of the steels kept the engine turning over longer per kick allowing it to start easier.