Help with my 01WR 426

Help! I have a 01 WR 426. It had real good power out of the box after I cut the throttle stop, took out the baffle, and the air box top off. I did want more snap though. While I was having the valves checked I had the dealer advance the ehxaust cam 1 tooth. The bike now is a gutless wonder. It has no tourque, no hit, and won't rev out. I have not jetted it yet because I am still waiting for the parts to come in. I ordered a YZ needle, 180 main, 50 pilot, and 100 air. I am currently running a Uni filter also. Does the bike run like a dog until the jetting is done? Have I made a mistake? I also disconected the "grey wire". I was just shocked the bike runs slower. Actually not just slower, its a dog! Please help!

I have the same bike,YZ timed/Throttle stop/Air box lid/Grey wire/Stock"DRR" needle @ #3 slot/MJ=#172/PJ=#45/Fuel screw=1 1/2--2turns out/ White bros."E" series S bend pipe w/ 12 discs & stock head pipe..Running @ 3000'--6000'and it just flat out RIPPS!!!!!

That bike shouldn't run like a dog @ all!! I ran mine w/ whole stock pipe & stock jetting w/ all the mods, clip on slot # 3, and the bike still ripped,runs alot better w/ new WB pipe though......Tim

The only other thing I can think of is the air filter being over oiled, because I switched over to a uni. It is one of those dual filter types, and I oiled both of them. I rode it around before I changed the filtet though, and the bike had no tourque, no hit. I am wondering if the dealer screwed up.

I've heard about the over oiling deal, about how it gets into the carb..Did the dealer oil it?

No, I oiled it. Still though, it ran like a dog before I even did the new filter. Stock with the throttle stop cut, baffle removed and the top off the airbox, the thing ripped. I kept hearing about how much better it was going to yz timing, so I told the dealer to advance the ex cam 1 tooth just like I have read to do. When you you used to hit a big wheelie, now nothing. It won't even rev out in top gear anymore.

Maybe the dealer advanced the wrong cam or went the wrong way with it. I would pull the valve cover gasket, and the timing plug and check that timing out!


Definitely take the cover and and check the alignment marks. I bet it's incorrect!


yes, check to see if they went the right way with the cam, make sure they did the right one, and didn`t bend any valves

Well wouldn't you think I would have valve noise if a valve was bent? I am not getting any valve noise.

Well I pulled the valve cover off, and found that the dealer did not advance the cam, they retarded it. I took a few digital pictures, and I am going to go to the dealer and have a few words with them. It really bothers me that the dealer mechanic is that much of an idiot. I will keep you posted on further developments. Thanks James!

Hold on, the exhaust cam is supposed to be retarded from the stock position. That would be the correct change. Look carefully and compare it to pictures of this change that have been posted in the "techical" section under "WR to YZ timing" (look to the left). This is offsetting the exhaust cam only.

[This message has been edited by James Dean (edited 07-13-2001).]

I printed out the diagram form this website, they had the cam at 11 o clock, not 1 o clock. I went to the dealer and discussed the change with the mechanics. I am taking the bike back tomorrow, and they are going to make the change. I am looking forward to riding it with the yz timing.

Well, I took the bike in today and we got the mess with the cam taken care of! Wow!!!!!!!!!!! What a diffrence in power! The bike runs like a raped ape! Can't wait for the Jets and the pipe! Thanks for the input.

Glad to here you got it fixed up right! Did you put the YZ needle in it yet? What needle code did you get?

Gobbler, Thats a prime example of why you should try to do that kind of work yourself. Why pay someone else to mess your bike up. Nothing agains pro MC Mechs, but it is not a very high paying field as far as wrenching goes, so you tend to end up with some lower skilled guys working on high tech bikes at the dealer level. Do Do happens though, but that was nothing a short test ride would not have shown. Good luck, let us know what you tink of the timeing change in the tight trials. I still have not tired this change yet, maybe next week.


I hesitated changing my timing to YZ because I suck at trail riding. I grew up riding the wide open spaces of California.

I did however make the change (thanks Mike C, Kevin, Mike M and Nick) I also went to the "E" series needle at the same time.

My feeling is the bike is easier to ride in the tight stuff. It doesn't make huge power from the very bottom, keep in mind I have the tapered header which is supposed to enhance low RPM HP. It certainly makes more than enough power for anything I encountered at Tower City and the power from the middle to the top is AWESOME :D




99 WR400f, YZ timed, MX-Tech suspension, Scotts steering damper, White Bros E-Series (12 discs), tapered header and a/f. Kouba T-handle for the fuel screw. Works Connection billet throttle tube and frame guards. Cycra Pro-Bend, triple clamp mount handguards. Thumper Racing rad guards, Renthal Jimmy Button highs, YZ Tank and IMS seat, YZ number plate, odo removed, EKP, 48PJ, 175MJ at 500-1000' Thanks James Dean!

I just got my jets today. so I will be putting them in soon. I ordered the stock YZF needle. I don't know what the part number is off hand, 50 pilot, 100 air. I wont get my main jets until tomorrow. I ordered a 172, 175, 178, and 180. I know what you are syaing about having someone else do the work on the bike, but I dont have the time, or the tools to run the valves, so I thought while they were in there, I would just have them do that also. I also have 2 tourque wrenched but neither would work for 7.2 foot pounds, so I would have had to buy that too. James, how much better is it with the YZ jetting, cause its pretty freakin good right now.


It's my understanding that the jetting requirements are different for a YZ timed and WR timed bike. You may want to search the subject.

I wanted to try the "E" series needle because of it's aggressive nature but, was told that the "E" needle and YZ timing worked best in combination. So that's what I did, changed the jetting and timing at the same time. You may not have to change the needle but, you may want to, if you want this type of power delivery.

Like I said, it still has good power at the bottom, just a little softer/smoother and the mid to high, it barks like a big dog :) The bike wheelied often before but now, I have to think about how much throttle I apply in the mid range or the front wheel jumps up :D The bike also revs quicker and makes the doubles out of corners easier.

Give it a shot, you won't be disappointed :D


Thanks Bill, my bigist concern is that the very bottom would be to abrupt and I would loose traction and ultra low speed menuvering finess. I will try it and see how I like it. I just wanted to try to dial all the carb settings in half decent before making radical cahanges, so I suppose once I get it running good Ill go screw with it so I can go through the whole thing again :) . Is the needle change mandatory with the timeing change? or can I scope it out with the stock needle?

My feeling with the bike now is that it has plenty of low grunt if you give it a good twist from low RPM, but is very well behaved running in 1st gear with little or no throttle. The weak part of the band seems to be the mid, I have a hard time getting the wheel up if I am in mid to high RPM and whack it. I hae a 172 main and will stick a 180 in it for this weekend and see how that works. May be I just need to shift sooner.

Yeah, Ill give it a try, but I think Ill wait untill I get more familier with the bike and decide on what if anything to add to it. I think Ill work on the finer points of setting the carb up and go to IMS seat tank rig and maybe that sweet GTRY pipe rig to shed a few pounds up high. Unless it needs valve adjustment when I check the valves.

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