Reed valves

[shredda]

Ok, I've searched around and even posted before but havn't gotten the direct information I'm after. My question is: Which reed valve (Boyesen Rad Valve or Delta V-Force 2) should give the biggest gain in top-end without sacrificing bottom on a 96 CR250.

Jetting is no problem for me. I'm only concerned about top-end, but dont want to loose any bottom. If you've used either of these products (especially CR owners) could you please tell me were you benifited (in the powerband) and how you like it.

I seem to hear a lot about how these help bottom end ( especialy the Rad Valve) but boyesen claims more top-end and the Delta 2 claims overall. I want to hear from real world people however.

 

[NO HAND]

I don't know anyone who had a chance to test both back to back but I know the different advantages in design of both. The rad valve uses some kind of separators to redirect and stabilise the flow for a symetrical distribution in the engine. Remember that the airboot makes a curve around the shock and the carb is at an angle before the manifold; so comes the need to realign the flow. Boyesen make alot of testing and they claim to make sure their product makes an improvement. I have heard people complaining that the rad-valve didn't make any improvements. The answer from a Boyesen rep was that the improvements were not necessarily felt by the butt dyno but were tested to give faster lap times and a better power delivery. Is that true? I don't know. I believe though that boyesen has brought up the rad valve as far as that conventional design can go. I know that the rad-valve has proven to be a good product. The thing is that Japan has been improving too.

The v-force has twice the reed area compared to a conventional reed cage. it does make a difference in the low-end responce that your butt dyno can tell, and does the same wonders on top. On a good engine such as a kx250 98-01, I hear alot of people saying that there is not much difference between stock, or v-force cage. On slower engines, like the 00cr125 the v-force is the clear winner. I think that v-force has come up with a technology breakthrough. I don't know if Boyesen will manage to improve still the conventional design. It's funny to think McGrath was using a v-force cage while he was sponsored by Boyesen? I think v-force has a better product but not enough to justify selling it twice as much as the rad-valve. In some cases, you may have more for your money with the rad-valve.

 

[YZmoto]

All I can say is that when I put the Boyesen Rad valve in my '94 yz 125 it didn't make any difference. I was disappointed, but luckliy I got it brand new off e-bay for only $30.

 

[gibbs_6]

I bought a v-force for my yz and on the butt dyno it added some bottom end and a felt like a wee bit of top.;)

 

[shredda]

Thank you NO HAND. Your information is great. YZmoto, did you change your jetting when you added the Rad Valve. I've heard that without changing your jetting it wont work well. Any additional info from others is greatly appriciated.

 

[YZmoto]

When I first installed the valve the bike ran poorly. Then I changed the jets and the best I could get out of fiddling around and trying different sizes was the same performance that I got from the stock one.

 

[cr-man]

Shredda- My brother had a 96 CR250 and I had a 95 with a RAD valve and I liked the improvement seemed to help a little everywhere when I sold my 95 I kept the RAD valve and put it in my brothers 96 and it worked real well in there also. I have not tried the V-force in the 96, but I liked the RAD valve well enough I would buy it again for the 96 it's a good performer! Good luck!

 

[shredda]

Thanks cr-man. I just went to the boyesen web site and it says their in house testing shows the biggest gains on the 96' CR250. I think I'm gunna get the rad valve.

 

[cr-man]

Shredda- I don't think you will be disappointed I was pretty impressed with the RAD valve on the CR it works! Good luck!