boyseen rad valve question

[mineralgrey01gt]

I won a boyseen rad valve set up off of ebay for $120 and they claim in the description that is a "rare" rad valve that is for the bigger carbs (38mm-41mm). Now did boyseen really make a rad valve that is set up for the bigger carbs? I got them in already and they dont really look any different than any other rad valve ive ever seen.

Also, what kind of gains am i looking to see with these? My motor will be in wednesday and its a bone stock 85 engine. Im getting the carb and everything with it, including electronics. I have a 38mm PWK carb that is going on it with these reeds but im going to ride it with the stock carb and reeds with just a pipe to see how the difference is

[Aceman]

Those guys on Ebay are boners! I fell for the same thing before I knew better. Usually what they are selling is a CR rad valve which comes with a 38mm boot. I tried to put it on my R, but the rad is shorter, needs at least a 1/2-5/8" spacer from what I could tell. The intake angle is greater on the CR valve than the 250r's also, looked like lining it up and keeping the boot from popping off the carb might be a problem.

I ended up just buying a 250r rad valve instead, it came with a 36mm boot. I just swapped boots with the CR, this one lines up better with the carb and doesn't require a spacer.

You can tell the difference though, on the CR rad valves the rubber boot sets into the reed block and on the 250r rad's the boot is held away about 1/2" or so. Boyesen sells these boots so don't think you need a CR rad just to run a 38mm carb.

[mineralgrey01gt]

thanks a lot. Its a 250r rad valve from your description of them. My carb fits them perfect, no problems at all. Ill see how it is when I put them on the motor.

Also where would the stamping for the RR and RL be at? I dont see RL stamped anywhere on mine so im guessing its the RR set.

[Aceman]

Are you talking about the part number stamped on the valve? If so, it's stamped on the triangle side of the reed block. I think 250r's are 04's.

[mineralgrey01gt]

thanks, they said on denniskirk.com that there is 2 different style reed pedals for the rad valve, the RL's and the RR's. I dont see anything stamped on it so im guessing its the RR's since they said it will not have anything stamped on it.

[brokenbones]

the 02a is the cr intake and the 04b is the trx style most people that run up here use the 02a cr style for more bottem end you have to change location of air box or run an open filter since the rad valve body is about a half inch shorter


i have a cr on my 330 and run a open filter with no problem if you run a 04b just call boysen and they will set you up with the proper in take boot

just my 2 cents

[86 Quad R]

if you've never ran a rad valve before i think you'll like the power it delivers. especially with a good exhaust, added compression and a good flowing air intake.

which reeds came with the unit, both fiberglass or fiberglass lower and carbon fiber outter?

[mineralgrey01gt]

both sets are fiberglass. I have a LRD adjustable exhaust. Im anxious to put them on and see how well they perform with the PWK carb. Im running an ESR trx filter kit so the no air box thing isnt a big deal at all.

Thanks for all the replies to this. This site is always a big help