BOYESEN 607 REEDS QUESTION

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gertie6car
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BOYESEN 607 REEDS QUESTION

Post by gertie6car »

:?

Should you use the original metal reed stop cage when fitting boyesen 607 reeds? My bike is fitted with them (previous owner) but just realised the metal cage was not used when they were fitted. Is this correct?

Thanks in advance,

Gert

PS I am so glad I bought a KDX and restored it, not had so much fun on a bike for years!! Thanks for the continued help! :supz:
gertie6car
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Post by gertie6car »

Come on guys, 11 views and no comments!!

gert
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RBD
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Post by RBD »

Hi gerbie6car,

The Boyesen 607 reeds do not use the stock reed stops. The 607's come with two support plates to clamp down the reeds.

Ron
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Post by fuzzy »

Thanks Ron!
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Post by gertie6car »

RBD,
thanks for the info much appreciated.

The reeds fitted have a small metal bar retained by three screws, a rectangular fibre reed and a rectangular reed with "windows" cut in it. The reed with windows is up against the reed block, then the solid reed and then the metal retaining bar. That sound right?

Cheers and regards,

Gert
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Post by RBD »

10-4 Gert,

That is how they go. You might want to use a tiny bit of "blue" thread-locker on the screw threads and do not over tighten them.

Ron
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Post by canyncarvr »

For future reference, don't forget the web..and your friend, google.

From: http://www.boyesen.com/cwo/OFFROAD/FAQ#2


Q: What are Rev-Plates?

A: Rev-Plates are the thin metal strips that are intended to be used, instead of the stock reed stops, to mount the reeds to the reed block. They allow the reeds to open freely and function efficiently.


Google search: Boyesen reed installation stops

Also, from the same search:

Q: What is the difference between single-stage and dual-stage reeds?

A: The stock reeds in your motorcycle are single-stage reeds. Single-stage implies that they are of a one-piece design. Their ability to function efficiently throughout the powerband is limited due to their inherent design. A thin, flexible reed will perform well at low RPMs, but does not perform well at mid to high RPMs. A thicker, stiffer reed will perform well at high RPMs but not at low to mid RPMs. Therefore, one reed of a given thickness and stiffness is not versatile enough to perform effectively throughout the powerband. The end result being that motorcycle manufacturers end up compromising on a reed of a given thickness and stiffness that will provide adequate response.
In order to overcome these limitations, Boyesen developed and patented the dual-stage reed. The dual-stage design incorporates a highly responsive top reed placed on top of a stiffer, ported reed for superior performance throughout the entire powerband. The top reed is lightweight and resilient for crisp throttle response at partial throttle or low RPMs. The stiffer, bottom reed is ported to provide maximum flow and horsepower at higher RPMs. Dual-stage reeds work in unison to perform efficiently throughout the entire powerband. The difference in stiffness between the top reed and the bottom reed allows the reeds to respond quickly and accurately to changes in engine pressure as you accelerate or back off the throttle. This translates into a dramatic increase in engine efficiency and performance across the entire powerband, from start-up to wide open throttle.



Now...I didn't say AND I'm not saying that everything you read on the web is correct or makes even a modicum of sense.

Oh...and you can even find pictures of 'em:

Image

A btw...but I've never seen that their dual-stage reeds make much sense. Look how much area difference there is between the two reeds...and the bottom/stiffer one is going to move to any extent?? And if it does, it's going to flow how much more air? Besides, if this dual-stage thing is such the hot ticket, how come their world famous RadValve doesn't have 'em?

Like I said...don't believe everything you read on the web. I'd believe it if I saw some hi-speed photography of them working along with some flow bench readings. Why not put something like THAT in their ads?

Gotta go. I'm ordering my EdenPure fantastic heater. It will heat my whole house AND cut my heating bills in HALF....all on a 15amp house current circuit!! Isn't that amazing!!! :shock:

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Post by lemmy »

Yeah, but the engine efficiency increase is DRAMATIC!! :rolleyes:
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Post by canyncarvr »

Who knows if that isn't all due to the reed on the top? I'm not arguing that they are not an improvement. They are.

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Post by TWMOODY »

Somebody listens to Paul Harvey to much ! :blink:
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Post by canyncarvr »

I can't STAND listening to him. OR his kid, either!!

Another thing I've wondered about is what happens to the flow pattern when the top reed lifts and the bottom reed stays. If it was a good thing to roil the hell out of the incoming charge, don't you think someone would make a reed cage that had a nasty lip on the cage itself?

'Smooth' rarified air keeps fuel in suspension better AND in better suspension at the same time..flows 'more'..provides a better intake pre-charge.

(Items like 'turboswirl head design' something completely different just in case someone wants to argue 'bout it.)

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Post by Jeb »

I'll bet what drives reedcage design is more about cost to manufacture and the ability to get the thing in the bike than optimizing performance.

And I'll also bet that optimizing performance - within the window given above - has more to do with the volume of the fuel/air mixture as well as the timing of the flows through both sets of reeds than turbulence: maximum flow at given times during the reed movements is best, and maybe that's what the "dual stage" is really doing for us. The turbulence is already there by the very nature of the velocity of the air through the port/reed whatever in relation to the air's viscosity. How well the fuel is dispersed in the air is probably met by the largest degree by the way it is metered in through the jets.

I think you're also right about the "smoothness" of the flow - no need to physically "knock out" the fuel from the mixture.

I'd like to see some slow-mo videography of the reed valve myself!!
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canyncarvr
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Post by canyncarvr »

The whole notion of expedient flow and keeping fuel in suspension in a 2-stroke is kind of funny anyway. Consider the convoluted path the intake charge takes from airbox to combustion chamber...and it's a wonder it works at all.

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Post by fuzzy »


I'll bet what drives reedcage design is more about cost to manufacture and the ability to get the thing in the bike than optimizing performance.
Indeed....Otherwise MX 2T's would be rotary valve.
'91 KDX 200 Project $300 KDX
'95 KDX 200 Project $600 KDX
'94 WR 250 Always a project
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