Start Jet?

3 replies to this topic
  • Nedley

Posted October 30, 2001 - 07:13 PM


I have been having some problems with my bike as of late. I recently spent three weeks in Fallon NV (4500 ft), and did some riding there. I was having some trouble with the bike not wanting to run at 1/8-1/4 throttle, I didn't do much about it until I returned to CA this weekend. I did the BK mod hoping that the reduced pump duration would lean out the slow lower throttle setting problems, That seemed to work fine, I only had a chance to ride it around the yard (I live on a Navy base so noise complaints can be a big deal). My question is that I was trying to dial in my jetting, so I put in a 45 pilot jet 1 1/2 turns out, stock needle on position 4 and 172 main. I looked in the manual and the other jet is called the "Start Jet". Is the start jet the jet that everyone refers to as the pilot air jet or is that something different. The start jet that I have in my bike is a 65 and everyone here is saying that they are running a 75-100 PAJ. That would lead me to believe that I would be actually richer on the slow speed circuit do to a 45 pilot and a 65 start jet. I need some help because the manual really screwed with my head on this one.
Thanks for your help,

  • Taffy

Posted October 30, 2001 - 09:58 PM


try to find in your manual some of your jetting settings. then post them here. because your bike is standard we may only need the year and model. chapter 7.

in your manual you'll see a picture of the front entry to your carb and it will have the MAJ and the PAJ next to each other. this can be found in chapter 4 from 4-7 to 4-17 with the picture i'm on about being in my '99 manual on 4-11.

finally at the back you have a tuning section in chapter 7.

leave your starter jet alone, this is not the PAJ. nobody touches this.

if you have slight bog you're running rich probably so all you can do until you post your settings here is experiment with your pilot screw in (preferably) or out 1/2 a turn.

i like to just jolt the throttle and see which setting gets me moving.

i made a little screwdriver to fit under the floatbowl by cutting the last 40mm of an electricians screwdriver off, grinding a flat face, and sticking it in a block connector. others buy a kouba something or other. but when something's for free and takes ten minutes ...

hope this helps.


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  • Nedley

Posted October 31, 2001 - 05:51 AM


I,m sorry I should have been more specific, I have a 2001 wr426 with a WB exhaust with 12 disks and like I stated earlier the jetting is a 45 pilot, 1 1/2 turns, 172 main, and stock needle with on position 4. The bog off the bottom is gone with the bk mod. The problem I was having was that the bike would load up when riding slow through rocks and such if you were not on the main jet.
Thanks for your help

  • Taffy

Posted October 31, 2001 - 10:30 PM


right, we've got a bunch of lads that we are slowly but surely weening off big PJ's. the dyas of the 48PJ are all but over.

buy a 42 and 40 PJ. also if you have a #100 PAJ this can be changed to a PAScrew and be turned to suit at about #75/85.

your needle (EMP) could drop to clip 3 then clip 2. you're MJ is well high and a 168/165 wouldn't be amiss.

do the MJ BEFORE yopu do the needle.

there are several lads running the above numbers, OK?



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