Reeds, Plastic vs. Carbon Fiber
joe_...@my-deja.com
I noticed that the new rad valves have carbon fiber reeds. The only
complaint I have with the power of my bike is right off idle, if you
gun the throttle, it will suck for air and die unless you let off...
You have to be going really slow and you have to gun the throttle
really fast. Would changing to the carbon fiber reeds possibly remedy
this problem? Would it be worth switching from plastic to carbon fiber
for 45 bux, or would I be wasting money?
Thanks in advance for any help.
Joe Leslie
'95 KTM 250sx
'88 Harley XLH
'94 Ninja 250
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EMARPLE
>I have the boyesson rad valve on my bike and it has the plastic reeds.
>I noticed that the new rad valves have carbon fiber reeds. The only
>complaint I have with the power of my bike is right off idle, if you
>gun the throttle, it will suck for air and die unless you let off...
>You have to be going really slow and you have to gun the throttle
>really fast.
This is a jetting problem that has nothing to do with the reeds. Have you tried
adjusting the air screw?
> Would changing to the carbon fiber reeds possibly remedy
>this problem?
I seriously doubt it.
>Would it be worth switching from plastic to carbon fiber
>for 45 bux, or would I be wasting money?
Yep. I couldn't tell any difference between the CF and the fiberglass reeds in
terms of performance. The CF reeds may last longer though. I won't know the
answer to that for another year probably.
Everett
'91 KX301...(tree-finder)
'74 BMW R90/6...(gentleman's express)
'75 Kawasaki 400 S3 two-stroke triple...(basket case, for sale, $600)
Martin Riggins
>I have the boyesson rad valve on my bike and it has the plastic reeds.
>I noticed that the new rad valves have carbon fiber reeds. The only
>complaint I have with the power of my bike is right off idle, if you
>gun the throttle, it will suck for air and die unless you let off...
Did you rejet after you installed the Rad Valve?
http://www.boyesen.com/products/motorcycle/install.html
has a .pdf file regarding jetting changes needed. One of the questions
in the .pdf file is "Why does my engine hesitate when I snap the
throttle?"
Their answer is "Poor throttle response comes from too high an idle
and/or the needle clip position is too lean. To test this, first check
the clip position (start in the third groove). If symptoms are still
there, turn down the idle adjustment screw until the symptoms go
away."
I've personally found I can tune any hesitation away caused by
temperature changes with the air screw without altering the idle
screw. My test for low end jetting is how well the wheel comes up in
second when snapping the throttle open. I know how it does it when the
jetting is on. If it doesn't come up as fast or far as it's supposed
to I adjust the air screw to fix it.
>You have to be going really slow and you have to gun the throttle
>really fast. Would changing to the carbon fiber reeds possibly remedy
>this problem? Would it be worth switching from plastic to carbon fiber
>for 45 bux, or would I be wasting money?
I don't think changing reeds is going to fix it. Fortunately, I think
the fix is a lot cheaper than $45. I think it will be free. I think
you should go a half turn in with the air screw and try it. Is it
better? If it is keep going in until it gets worse. Then back it up to
where it was best. If it's worse when you turn it in 1/2 then back it
out one full turn from where it is now (one half turn back from where
you started). Then keep going out until it cleans up. It will get
worse eventually as you back it out. Turn it back to the best place. I
always go in half turn increments as it's very obvious if your going
the wrong way i.e. whatever you were trying to get rid of is now
worse. Then I fine tune with smaller gradient turns (1/4, 1/8 etc.)
until it's perfect.
Martin
"This sport you must feel it from the beginning.
I feel it from two years old. I try to go faster with
a bicycle, a go-kart, with anything."
Juan Manuel Fangio II
joe_...@my-deja.com
> Did you rejet after you installed the Rad Valve?
Yes, I have messed with the jetting, needle position, and air screw. I
think I will focus more on the air screw now, because I know that my
jetting is finally spot on. I'll try what you recommend for air screw
adjustment. I suspect that part of my problem might be altitude. I
ride at 5600ft, and when I go to a place more around 1500ft (and change
the jetting), I loose the hesitation off idle.
I'll see if I can tinker with the air screw at 5600ft, and get the
hesitation to go away.
Thanks for both of you guy's help!
Joe Leslie