okieguy thanks for the repley and what may i ask did you end up with for your jetting?

I wish I had checked out this board sooner! I'm in the same situation that several others seem to be in with their '02 WR426's. I've been pulling my hair out for weeks now trying to get this thing to run.

I bought my bike on Jul03 and immediately uncorked the exhaust and took the baffle off the airbox. Since I was just starting the breakin, I left the throttle stop alone. After breakin was complete, I popped the grey wire out of the connector, completely removed the airbox cover and began running the bike harder (actually I should say trying to run the bike harder). After 2 weeks of trying both richer and leaner MJ, Jet needle settings, pilot screw changes, etc. the bike still runs like crap! I took it back to the dealer while I still had a warranty and they put the restrictors back on and tell me it is within spec, so I get to pay them for a couple of hours of diag time with no improvement...

Just an FYI for those experiencing similar problems, the guys at the dealer service centers don't seem to have an answer either. Their 'unofficial' response from Yamaha is that the bike needs to run YZ spec settings if the restriction is removed (02YZ426F stock: #42PJ, #162MJ, #EKR needle clip#4). I haven't ordered the YZ carb parts yet, but probably will (from a diff. dealer).


I purchased my new 2002 wr 426 on July 4th. After about 40 miles I uncorked the exhaust and put yz throttle stop in. The bike runs well so far. I have about 100 miles on it now, and will be removing the air cleaner lid, and cutting grey wire this weekend. So far stock jetting.

I have a question about Ifkerby's post. I thought that the uncorking of the exhaust and removing the air cleaner lid makes the bike run leaner due to more air taken in. The yz mj 162 is leaner than the wr 165. Also what's the difference in jet needles. I always thought by adding the free mods, one might have to jet richer to compensate?

Leaner main is needed because of richer(thinner)needle.YZ needles are richer than stock WR needles at the intial taper.Leaner main balances this out. :)

well i ordered a bunch of needles and jets they might be in by friday so we will see if i can get this thing running right i will let you know what i end up with for the jetting.

well recieved my jets and tried the ekp needle on clip 3 with a 45mj and a 100paj and 170mj and it is a little better but stil bad at anything past 1/4 throttle it seems to bog and somtimes spits back through carb does this mean it is too rich or too lean it also pops on decell but not a bad

you know what i hate this thing sombody come and get it before i go nuts this is the worst bike i have ever owned i give up i wish i had never bought it it sucks!!!!!!!!!!!!!!

it seriously is not worth the agrivation i do not have the time to screw with it so far i have spent 100 more time working on that damn carb trying to make it run than i have riding it i have a whole twelve miles on it make me an offer and it yours

[ August 07, 2002: Message edited by: blacksunday12101 ]

If you're serious about selling it-PM me... What do you expect to get out of it-since it runs so bad and all? :)

Believe me, I feel your pain. Not that I've gotten to dispise the bike, but it takes some getting used too. I ordered mine out of Canada and broke it in late June. Because it came from Canada it didn't have the throttle stop or gay wire so I didn't have to mess with it. I put on a FMF power core 4 and removed the airbox cover and the thing literally rode out from under me.

So for several months its been great...until this week. Kick, Kick, Kick and nothing. I tore the thing apart trying to figure it out. Then I signed onto TT and started reading posts and searching archives. First they helped calm me seeing that others have probs too, but the next thing I new I was pulling the plug and putting in a new one. Started on the first kick. The moral for my story is it can be the simplest things we overlook. I mean come on...I couldn't get it to start and should have immediately thought it was the plug. Going back to my 2smoke days that should have been the first natual thing to check.

Keep posting your situation. There are some really talented people on this board and love to help when they can.

You'll be spewing boulders in no time.

you'll only get more frustrated by throwing jets at it.

Slow down, there are literally thousands of jetting combinations, and unless you know your bike is identical to someone elses you can't just copy.

Make sure you have good fresh gas, clean plug, keep your hand OFF the throttle as you start it.

"running like a dog" really doesn't give anyone any info to help you.

is the bike new? has the timing been changed? is the rear brake adjusted so tight it drags? help US out a little!!

update took the bike in to the local guy that does all the racers bikes in this area to have him jet it. after a week he called and said he couldnt get it to run right either so i had to give him a pep talk to get him to keep trying. any way to make a long story short he gets another 02 wr 426 in a few days later for the same thing to jet it and set it up for racing he did this one with very little trouble so he decides to take the cdi off and try it on mine viola he was able to jet it and it now runs excelent just back from a ride it did cost me an extra 250 for the cdi but i was glad to know that i wasnt the only one having trouble jetting it who would figure the cdi was bad right from the factory any how the bike is awsome now!!!

[ August 28, 2002, 12:43 PM: Message edited by: blacksunday12101 ]

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