Looking for opinions and or experience with either product as to performance and installation. Is there any mods to be made to the intake boot ? Will i get richer with the reed cage change? Any and all help and opinions will be appreciated as to helping me make up my mind as to should i and if so witch one.My current mods are rev pipe, airbox , Boyesen power reeds , power core2, and jetting thats dead on.
I've only run stock reeds and the RAD valve. The RAD is much snappier, especially off the bottom, over stock reeds. Boyesen recommends leaner jetting with the RAD valve than when running stock reeds (if I remember correctly).
I went from the stock reeds and cage to the VForce III. Just bolt it on and go. No jetting changes required. Noticeable improvement form low through mid.
I have no experience with the Boyeson though so I can't give a comparison to the VForce.
I read a thread from another KDX only site on this very topic and the major players there indicated that the new VIII is a major winner. I believe it was compared to the same jump as going from stock reeds to the 609's.
Even though they said that going with the pro-reeds without the rad-valve would have about the same effect, I went ahead and got the whole assembly reeds and valve...
Right off the bat I noted that the response from idle to 3/4 throttle was as strong as before, but with much less of a hit in midrange. The power delivery curve was much more linear, and above 3/4 throttle the motor pulled noticeably stronger...
I came to find out that installing the rad-valve made the bike run overly rich and that's what was "smoothing" out the power curve :)
I went one jet size leaner than stock on both the main and pilot (from 145 main and 42 pilot to 142 main and 40 pilot) and I also raised the needle clip to the second position (lowering the needle to lean out midrange) and now the low speed throttle "snap" is much more pronounced and their is a significantly harder hit in midrange. Now that I've gotten more comfortable on the bike though, its not as much of an issue at all as when I was completely brand new and I like the characteristics very much...
Good luck on your decision! I'm certain the two units are pretty comparable in what they will give you...