Rad valve/ reed valve what's the difference?

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Jan 22, 2003
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#1
OK, I know it's really basic, but I don't know and don't want to look stupid in front of the guys at the shop. What does a Rad valve do, and why do some feel it's superior to a reed valve? BTW, why would one reed cage be better than another when it's the reeds that matter?
Thanks...
happy trails

Gordo
 

fatty_k

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#2
A reed valve is the actual name of he part, the reed valve assmebly. A RAD valve is the brand name of a special aftermarket reed valve sold by Boyesen, just like the Moto Tassanari reed valve.
 
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#3
There's a lot to your question. Guess that's why some businesses are formed largely to or exclusively for reed system development.

1. As fatty said.

2. There are different styles of reed cages and reeds. The rad valve from boyesen is a two petal reed sitting on a 45º cage. The delta forceII consists of an eight petal reed sitting on a 30º cage...actually two cages stacked atop one another. The dfII also has adjustable reed tension blocks (hi-lo) so you can set the tension to suit you. That simple adjustment makes a huge difference in the way the bike works.

Look around on the web (like http://mototassinari.com/) and you can see pictures of the two for comparison.

Obviously the above described reed valves will not act the same. There is much more reed tip area on the delta force than the boyesen and the º of the cage effects the rpm range at which each will work the best.

There are also choices of reed composition, mostly fiberglass and carbon. Within these classifications there are different designs having to do with reed stiffness, edge coating, single/dual (one may sit on top of another) and the like.

Oh...and besides the reed type/composition and the angle of the cage, there is the intake portion to deal with. Boyesen says the rad valve was specifically designed to resolve carburetor mounting-angle problems. Note that on most bikes the carb is pretty wonky compared to the cylinder.

You can deduce that, sitting smack dab in the middle of the air/fuel stream, a reed system can have a tremendous effect on how your bike works.

And so it does.
 

wanaride

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#4
CC, you were out for a while, we're glad to have you back!

Man, how in the world do you know all of this stuff? :worship: It seems that no matter what the subject is, you are completely on top of it. If I just knew 1% of what you know about the KDX...

Keep writing, and we'll keep listening!
 
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#5
Well, thanks...but..

It's not so much a matter of being 'on top' of anything as it is trying to pay attention and hopefully remembering 1/2 of what happens. ;)

I've used both the boyesen rad valve and the mototassinari product. It helps to be familiar with 'em both.

.....doesn't keep me from having an opinion about stuff I never seen!

When you get real old, you'll think you know a whole lot about stuff, too!

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