How did you re-jet your 426

17 replies to this topic
  • SoCalWR426

Posted December 05, 2001 - 07:07 AM


Finally I get this weekend off, I will YZ time & re-jet. I ride 3000-4000 ft
grey wire pulled,Euro YZF exhaust, lid removed. I thought I would start @ 172 MJ, 45 pilot & EVN neddle @ 3rd position.
What do you guy's think?
I'm very open to sugestions (Please!)
as of now without touching it Starts 1st kick w/choke & cold.
idles fine even when warm, give it gas it dies, pulled out choke then it would run @ fast idle, back poped bad on deceleration no power ect.ect.
Is this a good place to start my settings? if not what shoul I change.

Thank You
Happy Holiday's to you and your :)

  • SFO

Posted December 05, 2001 - 07:27 AM


Hey dude...
My bike runs great 0-5000 ft with...
155 MJ
EKP #3
45 PJ
I am back to running the stock pipe as a ranger nixed my ho-made sparkarrestor...
I didn't notice a performance loss either...
It will gurgle like a sick step child if I run too big a main, BTW, :)

  • yzernie

Posted December 05, 2001 - 07:33 AM



I live at 4000' and ride mostly 3000-4000'. I have a YZ but when you make the changes to timing and such it should be the same.

BK mod
45 pilot
stock needle 3rd from top clip position
168 main
fuel screw 1 turn out

I run race fuel so I can jet a bit leaner than if using pump gas. The bike flat out rips. Runs well at these elevations. I went to Saddleback yesterday and it was FAST there too. These jet settings seem to be good overall. I have played around for a few weeks and this is what I'll stay with.

Where the hell is Fillmore????


  • Dan_Lorenze

Posted December 05, 2001 - 08:11 AM


My bike is set-up exactly like Ernie's bike with Bk and YZ timing, and my bike too just flat-out rips and I can't get the thing to backfire at all. Just clean running a gobs of ripping power!! 1st kick. :)

  • SoCalWR426

Posted December 05, 2001 - 12:59 PM


I guess I'll reply in order.

After we last talked & exchanged info. I bit the bullet & bought a pro moto billet spark arrestor, pricey,
but as you know high quality is worth every penny. I would recomend it to all. It's also U.S.F.S aproved.

Fillmore is between Ventura & Valencia off of hwy.126. Was a sleepy litle ag town, now growing fast with new homes. It's interesting that you and Dan run the same, but as you ride a YZ, I assume your running the EVR needle as it's stock for YZF (per dealer) and Dan run's stock WR needle

First of all. Congrats on your recent win!! I've never meet you and yet I still feel proud of you through our relation on TT. I bet the chicks really dig it eh!! Lots of autograph action!!(LOL)
I will try your settings. It really gives it some thinking as you and Ernie run the same only diffrent needles, did you try the EVR needle? I assume that since both of you mentioned a leaner jet because you guy's run race fuel I will be running pump gas that I will have to go 1-2 sizes fatter.(170-172?) let me know your thoughts..

  • Dan_Lorenze

Posted December 05, 2001 - 01:20 PM


Socal, Thank you very much for the kind words. My needle is stock in the middle position (I think it's the 3rd). When I changed my timing my Yamaha mechanic told me to try the 168 main. I run at sea-level running pump fuel. I don't want to open up ye ole can of worms with race fuel, call me crazy but my bike runs best on the crap that you buy at the corner station. I has been explained to me a thousand times why race fuels are better but the seat of my pants tells me different.
Im going riding on Sunday and you are more that welcome to join me and my friends, no were not riding around "Egg City" (Filmore) but were going to Mojave (Moe-jave). :) Good luck!!!

  • SFO

Posted December 05, 2001 - 03:22 PM


I spent three days on the dyno trying jetting combinations and race fuel blends.
I also played with mtbe.
I can send my results to anyone who is interested.
I got the best #'s with nutec but availability issues coupled with the price wasn't worth an additional 2hp.
Next best was 92 octane pump gas.
My testing with b37 and mtbe proved to be a wash.
I believ the stock ignition will not allow you to exploit real fuel. So we tried the vortex ignition with the standard curves and still no better than stock.
I am running b32 now but it is more just plain voodoo than anything I was able to prove on the dyno.

  • SoCalWR426

Posted December 05, 2001 - 03:48 PM


:D Egg City!!!
Dan you have Fillmore confused with MoorPark & Grimes canyon..After all spell Moorpark backwards and you will know how it used to smell the way,Egg City went out of businss :) Awww crap, just agreed to work sunday. Volenteered to cover for a coworkers shift as his 5yr old daughter is having a B-day. Friday is my only day open, saturday I have to do the X-mas honey-do's :D
Thank you for the invite, perhaps I can invite myself at a latter date?

  • James_Dean

Posted December 05, 2001 - 07:05 PM



Don't run the EVN in the 3rd clip. Sorry, but you have the wrong needle if it is stamped OBEVN. The OBEVN will need to be run in the very bottom clip position (richest possible) to be close, and will only be equal to the OBEKN#2. This will be a little lean.

If you actually have OBEKN, then the #3 clip would be good.

(OBEKN is part no. 5JG-14916-EN)


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  • SoCalWR426

Posted December 06, 2001 - 06:14 AM


Holy Heck!!
Thanks JD,
My part #is the last 2 digits are different. What do I have and whats it good for? I tried following yours and Taffy's 6 miles of posting and only got a migrane out of it. If you noticed Dan runs a stock WR needle and I assume YZErnie is running a stock YZ needle. I naturaly thought that with YZF exhaust and YZF tuneing that a YZF needle would take us were we all want to go...MORE POWER!!...So which needle set-up do you think is best YZ or WR?
Once again Thank you for stoping me from making a huge mistake

  • LarryCO

Posted December 06, 2001 - 06:50 AM


Depending on the year and model, I believe Yamaha changes the jet needles. Thus, saying that your needle is "stock" doesnt necessarily equate to another person's "stock" needle. For example, the "stock" 2001WR needle is a DRR...while the "stock" 2000WR is probably something different.

Go with James' suggestion. You wont be disapointed! EKN... clip #3 or so...


  • James_Dean

Posted December 06, 2001 - 09:22 PM


Look at the needle for the code. Based on the part number you gave, it should be OBEKR. This is not what you described earlier.

EKR is the stock '00YZ426 needle. Give it a try in clip #4 with the 45 pilot, 1 3/4 turns out and #172 main. It will roost!

(That's what the new 2002 CRF450 comes with stock) I like E-N and E-P a little better, but yours will do.

  • SoCalWR426

Posted December 06, 2001 - 09:45 PM


Thank you for your time and your help
I can imagine it must be a pain to answer the same questions as often as you do. Friday morning I will put your advice to work. I was wondering though, how come your sugesting a 172mj and the other 426 guy's (even the YZ) are running 168mj.

Thanks again

  • James_Dean

Posted December 07, 2001 - 07:41 AM


The 172 main was because you mentioned it first. An oversight on my part, at your altitude the 168 will probably be better. You will have to judge that part by how it feels, the weather, phase of the moon, the color of your mood ring... :) Did I answer this before? The new CRF uses a #175, the YZ426F has a #162, the YZ250F a #175. Whatever, as you see, it's in the range.


  • SoCalWR426

Posted December 08, 2001 - 05:35 PM


I finished my mission..Thanks to YZErnie & Dan L. jetting was spot on!
Special Thanks to James Dean for preventing me from making a drastic mistake. As it turned out I did have the right needle but read it wrong. (My eye's must be getting worn out) Big test will be my next day's off.
Here's what I did.
(1) YZ timing.
(2) YZF Euro mod.exhaust.
(3) Pro-Moto billet spark arrestor.
(4) Jetting = 168mj 45 pilot.
(6) YZF stock needle pos# 3.
(7) YZF L & R side plates.

1st, Impresions, Ernie, Dan, your right this thing RIPS!! 1st.2nd.3rd. gears the cross bar is pinned to my chest! 4th. gear front end just rolls up into a nice wheelie...Went over some small washboards bike is much thinner with the YZF side plates, Feels much better. Now I have to decide what tank/seat combo. I'm open for sugestions..
Once again.....THANKS ALL
Oh yea! If you need a good laugh, read my post about dropping a socket while doing YZ timing :)

  • yzernie

Posted December 08, 2001 - 06:33 PM



I knew you would like it!!! I remember where Fillmore is when you described it. I used 126 to go to my sisters when she lived in Camarillo.

Maybe we can hook up and ride sometime.


  • SoCalWR426

Posted December 08, 2001 - 08:15 PM


Better than I could hope for! All seems perfect.Throttle response is awsome, no lug or hesitation. You can wick the throttle from idle and it just explodes! no hesitation and it,s super crisp.
It would be great to get together for a ride. I was bummed when I had to pass on Dan L's offer to ride with them as I have to work tommorow. I do a lot of mid-week riding if your ever up for that. Please keep me in mind for your next ride I would love to go

  • Dan_Lorenze

Posted December 09, 2001 - 07:17 PM




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