99 WR400/FCR carb jetting guru's come forth!

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Hello,

I have dismantled my fcr gen 1 for cleanup and damaged 1 jet in the process. This does not have any thread in it and is just a push fit in the carb (the reason why i damaged it is because i tried to unscrew it instead of slightly tap it outwards). Unfortunately I cannot locate this part on an exploded view of the parts.

This jet is situated on the air filter side and protrudes in the circular part infront of the sliding valve. When you rotate the throttle the slide valve rises and this jet squirts on the engine intake.

If anyone has experience of the mentioned jet I would like to know please;

- What is the technical word used for this jet (to hopefully locate it on a drawing)

- Is this a standard jet/ one size

- Any supplier of this jet

Thanks

Adrian

Edited by Adrian C

If you look here http://www.jetsrus.com/index.html they call those parts the main and slo air jets. You may be able to get those from that supplier.

In case anyone is looking for the terminology of the above mentioned post (Posted 31 July 2013 - 07:10 PM My same post)

 

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If anyone has experience of the mentioned jet I would like to know please;
- What is the technical word used for this jet (to hopefully locate it on a drawing) - 
Accelerator pump nozzle jet
- Is this a standard jet/ one size - Standard jet is with 1 jet hole, Non standard jet is with 2 jet holes (but FCR must be with a leak jet bowl)
- Any supplier of this jet - Found a supplier on the web (easy once you search with 'Accelerator pump nozzle jet')

 

Regards

Adrian

I have been looking online, and I am having a hard time finding the AP actuator arm in any of the diagram's.  It doesn't appear to show on the schematics for OEM Carburetor.  Mine appears to be wearing, as the actuator arm/pin is somewhat loose in the hole that it sits.  I am referring to the black linkage arm that directly moves the AP pin.  

 

I have a 99 WR400, and since the carb is apart, I figured I would go through it and make sure everything is tight and working well.  I have done the AP diaphragm mods, but the Tokyo mod spring is too small for the AP mechanism, so that sucks (the straight extension is waaaay to short).  I'm getting this ready for a season of racing enduros, and hopefully at the end of this season, I will be picking up a leftover 13 or 14 WR450.  I just want this well dialed so I can give it to my kid when the new 450 rolls in.

 

Any suggestions where to find the black actuator arm?  Thanks.

 

 

The tokyo mods spring is for the FCR CR/MX, from 2003+.

You cannot use that spring

You have to use safety wire to link the throttle and apump linkage together.

 

Go to Sudco.com for diagrams and part numbers

The tokyo mods spring is for the FCR CR/MX, from 2003+.

You cannot use that spring

You have to use safety wire to link the throttle and apump linkage together.

 

Go to Sudco.com for diagrams and part numbers

Thank you for the reply.  I have used a band included in my JD jet kit to tie the linkages together.  Another question for you KoolAid.

 

1.  The extra space that is present in the black linkage that holds the AP pin, could wrapping safety wire, say 4-6 times, would that be adequate fill the extra space in the pin holder to take up the mm of slack that I am sure is creating some of the bog?

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2.  I have measured the depth of the Boyeson AP cover, which is the same depth as the diaphragm bracket that sits with in it.  My AP would not work or move due to that measurement being the same, and the squirt was almost non existent.    I ground down the pin on the diaphragm about 2mm, and now it squirts well, but what appears to be too long, about 2 seconds.  The goal is to be around .5 secs if I am not mistaken, as there is no leak jet present in this year carb to help offset that amount being shot by the AP, correct? The squirt does not hit the slide either (But in a side note, the float valve was cracked almost all the way through.  Dodged a bullet there.)

IMG_2533_zpsc3e68331.jpg

 

 

If I put another diaphragm in and grind down the pin again, adjusting the pin length, less removed than what I did before, that should lessen the AP squirt time, correct?

 

I only ask, as before I ground the pin in the diaphragm down (when it was tight in the cover and the AP pin did not move), the bog was present.  I imagine this bog with no AP movement was due to no fuel being shot from the AP.  Conversely, too much fuel also causes the bog, so the trick is finding the sweet spot ( at <.5 secs, right?)

 

Thanks for your help.

New Float valve installed, AP mods complete, R&D Fuel screw, JD Jetting Needle and settings and new Q4 installed.  New top end freshly done, too.  Only been putting around the yard a bit until the trails open here in NH, but holy crap.  1-3rd gear wheelies are a snap, NO bog or hesitation.  Thanks to all for the input.  My 99 has new life breathed into it.

 

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