Carb Gynecology 101


8 replies to this topic
  • jimmym

Posted September 23, 2014 - 07:11 PM

#1

It is truly possible to swap out the main and/or pilot jet with the carb still on the bike?

 

I needed to change the main jet trailside on my 2011 due to a lean condition.  I've heard stories where guys were able to swap jets through the 17mm opening in the bottom of the carb, but keep in mind that I've never met any of these guys in person.  But I was ready for the challenge.

 

I have a plastic jet tool, but it still took several minutes to remove the jet working through that tiny hole. I spent 10+ minutes trying to start the threads on the new jet, but couldn't get it started cleanly.  I decided to rotate the carb to get a better view, but loosening the screw on the boots and removing some hoses still didn't let the carb rotate enough to get a clean view.  After nearly mis-threading the new jet for the umpteenth time, I gave up and removed the subframe, shock, exhaust... you know the drill.  

 

Perhaps my fingers are simply too large, and I chose the wrong profession, um, err, bike for such trailside maintenance.  Can anyone actually confirm whether this is possible?  If so, what are your methods and tricks to making this a painless process?



  • Krannie McKranface

Posted September 23, 2014 - 07:23 PM

#2

Yes, many do it.

I've done the last several WR pilot changes this way.

The trick is to rotate the carb and use a Motion Pro FCR tool, or similar. Without a flat rachet, it's just harder.

It's no big deal, just a pain.

I lay the bike down on the ground facing the sun, so I can see better.

I use a tire iron to twist the carb and hold it in the most twisted postion.

 

So why do you have to do it trialside?

The main jet is for 3/4 throttle to WOT. You can ride with it lean or rich, no problem.

It's when the pilot is off that makes it unbareable.



  • stevethe

Posted September 23, 2014 - 07:23 PM

#3

You get one of these http://www.harborfre...iver-92630.html

 

Get a longer 2" screwdriver bit for the pilot jet. Start it with a thin piece of tubing. The main jet you can get with the same tool and a socket bit. Once again it can be started with a piece of tubing.



  • jimmym

Posted September 24, 2014 - 04:54 PM

#4

Great suggestions! 

 

Laying my bike on its side is never my first thought, but in addition to twisting and holding the carb I think this will work. Getting the threads started was my primary issue, but I like the idea of using tubing and peeking under the covers.  

 

As far as doing this trailside, it was actually more like truckside.  I was a couple hours from home, had a serious popping issue on decel, and wanted to fix and test the issue before I took her home.  Plus, I really thought the swap would be fairly simple.  :banghead:   

 

Next time I'll be better prepared.  Thanks again



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  • Krannie McKranface

Posted September 24, 2014 - 08:15 PM

#5

Great suggestions! 

 

Laying my bike on its side is never my first thought, but in addition to twisting and holding the carb I think this will work. Getting the threads started was my primary issue, but I like the idea of using tubing and peeking under the covers.  

 

As far as doing this trailside, it was actually more like truckside.  I was a couple hours from home, had a serious popping issue on decel, and wanted to fix and test the issue before I took her home.  Plus, I really thought the swap would be fairly simple.  :banghead:   

 

Next time I'll be better prepared.  Thanks again

 

Decel is pilot only

Usually just a fuel screw adjustment will work for the day until you can get the correct pilot

Get an R&D fuel screw



  • DunmireD001

Posted September 28, 2014 - 02:26 AM

#6

Yes I always do this. Loosen your rubber carb mounts so that you can twist the carb sideways, so that you can access the bowl screws on the bottom of the carb. (The 2 screws on the far side can be tough.) then once the bowl is off, just use a flathead screwdriver to unscrew them from their locations. Be careful not to mess with the float.

  • stevethe

Posted September 28, 2014 - 04:48 AM

#7

Yes I always do this. Loosen your rubber carb mounts so that you can twist the carb sideways, so that you can access the bowl screws on the bottom of the carb. (The 2 screws on the far side can be tough.) then once the bowl is off, just use a flathead screwdriver to unscrew them from their locations. Be careful not to mess with the float.

 

07-11 you don't take the float bowl off only the nut.



  • DunmireD001

Posted September 28, 2014 - 09:27 AM

#8

07-11 you don't take the float bowl off only the nut.


You're probly right. I'm referring back to my 01 wr426 that doesn't have a nut. I have to pull the bowl every time.

  • 1trackmind

Posted September 29, 2014 - 01:25 PM

#9

Be careful of the "hot start nut" when rotating the carb. I happened to break mine. 






 
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