Jetting Settings What do you guys think?

I want to start by saying thanks for all the help for us "newbies".This IS my favorite website. I am looking into jetting my stock 02 wr426 and I have looked through the archives and found some similar settings for my area 7500'-12000'. I found that LarryCO, Wickedcrash, and Dodger all use a 38pJ. I called up Excel Motorsports and the guy told me not to use a 38pj because its too lean. He suggested a 45pj and 150-158mj and couldnt believe that I wanted to put a 38pj in there. So once again I call upon the knowledge of all you fellow thumpers to help me in this. I am thinking about trying one of the following to start. EKQ#3/158mj/38pj/2 3/4out on screw(Dodger's) or 148mj/38pj/EKQ#1/stock air jets(Wicked Crash's) Does excel motorsports know what he's talking about? I just want my bike to kick ASS!! Thanks Guys

he talks outta his arse boy!

i would get the P needle. EKP for your altitude. or get the two and comeback and tell us the difference. your start height for the needle canonly be a guide and you should spare some time to actually tryu it up one and down one just to know the difference.

the 38 PJ should be matched to a smaller pilot air jet and i would recommend around a #60 and most definately not the #100 that's in it at present.

with any of these things, nobody here wants to give you lean settings and we have all sussed one thing and that is that a rich running bike will always run ok!

it's big and we look cool!

so it depends if you want to get off your bum and go to the edge with a bit of sweat. easy to yes, harder to do!

good luck.


LOL! Once again, the local Excel shop has attempted to repress us thumpers! Geez...if I had a nickel for every time someone at that shop either gave me a funny look or recommended me NOT jetting the way I do, I wouldnt need to find another job, play $50 in lottery every week, search through garbage cans for good stuff, etc. :)

Thru fairly extensive testing out here, I've come to the conclusion that the following is about the best you can run:

5500-10K ft:


10K-13K ft:

38PJ/65PAJ/EKQ#2.5 or EJQ#2/145MJ/160MAJ

Given that it's almost winter now, you might consider going up a step on the MJ for each of the two above (to a 152 and 148 respectively), if you try these and they seem a bit too lean from midrange up. Also, the EKQ needle works pretty well down lower (5500-9000), but I've found that the EKP is just a bit better in that range. Your call...

Get the MJ's, 38PJ, and needles from the shop (and tell them they're idiots!)...and the MAJ and the adjustable pilot air screw/spring setup from Sudco.

Good luck...and dont take ANY jetting suggestions from the shops! They should know what they're doing, but they dont...


YZ Jet Needle Part #'s:

EKQ 5JG-14916-E1

EKP 5JG-14916-EP

Look at my signature this set up seems to be working pretty well for me, but I am no jetting expert. I have just been messing around with it but this current setting works fires first kick cold, and I hardly have to use the hot start.

Thanks guys for the input. Larry, you said to get the adjustable pilot air screw/spring combo from Sudco. Excuse my lack of knowledge but what exactly is that? Does that take the place of the 65paj that you mentioned or is the same but adjustable?

That's it, I'm not going to pretend I know anything about jetting anymore until I find out what the heck is going on with my bike :D. My scoot is so finiky, it never runs the same ride to ride.

Get this, last Sunday was spent roosting Rabbit Valley, right around 4,500 feet, temps in the low 70's. Just went to a richer main last Friday (162) to get rid of a flat spot right at about 2/3 throttle. Seemed to work fine around Boulder (was only a short test ride), and damn if my bike wasn't running the BEST it has ever run, hard pull bottom to top, absolutely no poping or backfiring, it was perfect.

Last night, I took the time to wash all the mud off, being carful to cover the air box under the seat with a towel (air filter only mildly dirty, not enough to warrent cleaning just yet), plugged the exhaust and what not............Got on it after drying to spin it around the neighborhood for a final ran like total sh%&, poping and backfiring, cutting out anywhere above 1/2 throttle, TOTAL sh%&. What is going on here?????????????? I'm only 1,000 feet higher here in Bldr, it was only 10 degrees cooler, this shouldn't have made my bike run that much worse.........right?? Just can't understand why won't my bike won't run the same weekend to weekend???

Guess I'm going back to my baseline recommendations from Hick, and see where I'm at. Does it seem like I'm missing something here confused.

And hey Jason I got your e-mail, sorry I have'nt written back just yet, I'll get back to you today, just been a little busy..........


Dodger :):D

Dodger, is it possible that you got some water in between your wire connecters? I did this once and my bike ran like crap until I opened them up and dried them out. I used a blow dryer. The one that ties into the carb in particular seemed to be the wettest. I don't know maybe it's a starting place? Hope it works out.

Very, very possible I guess...........if so, would explain last nights fiasco. Didn't really know that would make such a difference since we soak our bikes on trail rides.......but would make some sence. I'll see how she runs when I get home tonight.........I really need to pull the plug that's in there right now to see how it looks........

Dodger :D:)


You can see from my sig line that my jetting is a little richer than most. Excel gave me the same set up when I talked to them, but, when I tried it, it was really sluggish on the bottom and had monster hit on the last part of the throttle. It would almost yank the wheel up when you came into it. Climbing a hill was tricky, if you hit the powerband halfway up the hill you should probably be sitting on the front fender to keep the wheel down. Even now with my current jetting, I stay well forward on this beast. They (excel) mean well, but they don't ride this beast. When I told them what my jetting was they didn't believe the bike really ripped the way I said it did.

Overall, unless they ride the beast, I don't believe they can work on it.

What I would really like to do is get together with some other Denver area riders and see what their jetting produces compared to mine.

Good luck



The pilot air screw/spring (referred to by many as the PAS) is an adjustable screw...which replaces your PAJ. Based on the # of turns out from fully seated, you get varying PAJ values. Dont have the chart in front of me, but for e.g. 1/2 turn out = 65 PAJ, etc. You'll never have to buy another PAJ this replaces all PAJ's. It's only about $10...and well worth getting.

Could someone post the chart for PAS settings? Or Blue, you could just search on "pilot air screw" and look there. It's posted out here more than a few times...

Good luck!

Racemile, Are you still using your stock maj and paj as well as the stock needle? Have you done the bk mod or acv mod and would your jetting set up still work with those done? BTW I agree about us members in the Denver and surrounding areas should get together and compare or just go roost! :)

This is what I'm using. The Main may be off but the pilot and needle are about perfect. Not sure if I am lean on the Main or that is my Rev limiter kicking in. I don't spend too much time at WOT to make a good determination. My buddy uses similer settings on his 02.


Larry,Do you have the Part# for that adjustable pa screw and spring combo?

I sure dont. But if you tell them that you want the "adjustable pilot air screw", they should know what you need.

Blue Dragon, I sympathise. I thought I had my jetting sussed, but a small drop in temperature had me fall outside of my carb setting comfort zone.

My fix was easy enough, dropping the needle down one clip to lean my mid throttle range out - it went from one day to then next from working well to surging, popping and backfiring blue puffs of smoke and completely unrideable.

The one clip change worked absolute wonders for my problem but I think I will still be too close to the edge of the comfort zone so I'm gonna go for a different needle with more clip adjustments.

Maybe you are operating below the 'range' your carb settings run at. Kind of like a hi low on a stock chart which you dropped off of?

As for a remedy to your specific anguish, I'll reserve that for other more knowledgable people.


The settings in my sig are the only things I have changed. I am still running the stock needle and the stock air jets. I have not done the bk mod or the acv mod because I am happy with the way the bike runs right now. I am sure that doing these mods will make some changes but I would assume that they would be positive since you are still creating a better beast.

If you try it let me know what you think, positive or negative. I may have hit the nail on the head or I could be riding a much tamer beast than everyone else.


P.S. just got your pm this morning.

Sudco part numbers for PAS

Screw: 021-230

Spring: 021-235

Thanks Sabin for those numbers. They're on the way :)

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