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Author Topic: Boyeson reeds - rejet required  (Read 2767 times)

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Offline subarumy98

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Boyeson reeds - rejet required
« on: February 04, 2009, 11:48:21 pm »
HI All

500XC with now the correct tailpiece and stinger section.
Also installed Boyeson reeds and now wveryhting is wrong.

lean on the bottom (slow to idle down)
rich on top, (does not rev our clean at all)


What happened to the advert that said install and go roost someone ?

:)


Similar results for you guys up here ?
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ZundappGuy

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Re: Boyeson reeds - rejet required
« Reply #1 on: February 05, 2009, 01:30:06 am »
HI, I have used Boyeson dual stage reeds in the past and was unhappy with the top end performance, they did give a small increase in botton end power????
I currently use Mossbarger 6 petal reed cage on my Zundapp 125, They have many Vintage applications. check them out at
http://www.mossbargerracing.com/product1.htm



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Offline Lozza

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Re: Boyeson reeds - rejet required
« Reply #2 on: February 05, 2009, 07:05:48 am »
That's because the top petal flexes easily and as revs rise they flutter badly.Because of this there is never enough pressure to lift the bottom stiff petal. Spot on Zundapp.
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Jesus only loves two strokes

husky61

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Re: Boyeson reeds - rejet required
« Reply #3 on: February 05, 2009, 08:11:52 am »
Similiar experience with both our CR & XC - 500's.

The standard reeds work much , much better and the big advantage is you dont have to spend precious hours dicking around with the jetting for very little or no gain.

Its a 500 and doesnt need any mod's ?????.
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Offline subarumy98

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Re: Boyeson reeds - rejet required
« Reply #4 on: February 05, 2009, 06:16:14 pm »
SHIT !

Problem is, I have made 2 changes in 1 step.

The exhaust was incorrect as follows:
- the last taper section, about 25mm at the end of the expansion chamber was missing
- the section joining the expansion chamber to the stinger was 30mm ID, as opposed to 25mm
- the tailpipe core diameter was >40mm as opposed to 25mm
- the tailipipe volume was incorrect


So, all of the above have now been corrected, but I had jetted to match the old pipe.

I have also now installed the Boyesen reeds because I had them.

Current jetting is as follows:
Pilot      40
Main     380

I have the following:
= slow to idle down
= blubbery on toip, does not rev clean

So your suggestion is to go back to the stock reeds and re-jet from scratch ?

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husky61

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Re: Boyeson reeds - rejet required
« Reply #5 on: February 05, 2009, 08:46:59 pm »
Yes

We had all sorts of drama with the 500's in the set up described and they never ran really really well. good but not what you would expect.

So we went back to new set of standard reeds and it was much easier to jet . In the end both our CR & XC 500's run really well.

Good luck with it .
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Offline PEZBerq

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Re: Boyeson reeds - rejet required
« Reply #6 on: February 05, 2009, 10:13:36 pm »
What fuel mix are you using?

I had jetting problems with my 430 XC after rebuilding and installing Boyesens.  I first went back to stock jetting and fitted the OEM reeds.  Then sorted the jetting out using stock reeds (downloaded Mikuni manual from TD Hatrick website).  Found stock jetting too rich for 32:1 fuel I was using.  Ended up with 400 main and 20 pilot.  Then fitted the Boyesens again and they worked great.  Probably could go down a size on the main but wont as I am happy to run a little more fuel to keep it cool.  Good luck - hope you have a few jets to use (I went in steps of 20 on the main)
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Husqvarnas: 78 390AMX, 82 430XC, 84 240WR, 84 500AE, 84 510TE, 87 510TE

Offline subarumy98

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Re: Boyeson reeds - rejet required
« Reply #7 on: February 06, 2009, 01:44:24 am »
Thanks for the info:

I am running 40:1 BelRay HR synthetic on 93 unleaded fuel.

Your final jet sizes are exactly the opposite of the direction I thought I should go !!
I had a Mikuni jetting doc - will dig it out for bedtime reading.

Just for comparison, please can the other guys publish their final jets selected as follows:
Model        = AA
Altitude      = BB
Pilot          = XX
Main          = XX

I need to make sure I am ahead of Team Maico !
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Offline PEZBerq

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Re: Boyeson reeds - rejet required
« Reply #8 on: February 07, 2009, 10:04:27 am »
40:1 is probably much richer (more fuel per slurp through the carby) than Husky used when setting the original jetting specs. They probably used 20:1.  Might explain things a little??? 

Out of interest I have read many tests of different fuel ratios showing 20:1 or even 16:1 giving more horsepower than higher fuel:oil ratios - 30:1 say.  Problem is the oiling up of the exhaust system with so much oil.  The extra oil lubricates better and helps HP according tho the articles.  If interested check out http://www.bridgestonemotorcycle.com/documents/oilpremix6.pdf

cheers Steve

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Husqvarnas: 78 390AMX, 82 430XC, 84 240WR, 84 500AE, 84 510TE, 87 510TE

Offline subarumy98

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Re: Boyeson reeds - rejet required
« Reply #9 on: February 09, 2009, 03:54:23 am »
@PEZBerg:
Oh joy - now you have confused me even more :)

I have been using 40:1 synthetic oil in everything for consistency reasons. Even the Raio Control buggy gets it.
Let me go think a bit more.
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