My First Ride on my Wr426F, questions and comments.

18 replies to this topic
  • ljparton

Posted July 20, 2008 - 09:30 AM


So yesterday i decided to ride my WR426F for the first time, i bought the bike about a week ago.

I pull up to the riding area and gear up and she starts second kick. I got the starting drill down pretty good, i've been practicing in the garage lol. So i headed to the trails.

My last bike was a 2000 YZ125-The 426 is 43lbs heavier the mammoth fuel tank! So i was expecting to be struggling with the weight all day. But i found that the weight is only noticeable when going really slow, and on some corners on the track. I've heard the YZ tank/seat helps with this.

The bike has power everwhere, i havent even looksed to see if the free mods are done yet, but i think they have because i experienced no off-throttle bog. It has the GYTR Exhaust insert and is geared 53T in the back. It will tractor up anything you tell it too.

Suspension is good, but nt for my weight. I'm about 220lbs and it just kills me on high speed bumps. My kidneys are hurting today! But i figure that a revalve is inevitable anyway.

Hot starts! Wow, it only got hot twice and both times it required a few kicks and the hot start pulled out. It was a bit of a pain but not too bad.


Is the 03 Auto Decomp Cam worth the money? How hard is it to install? How much can i fin one for?

What Spark Arrestor Exhaust Sytem is the Cheapest and best? Will 450 pipes fit?

Can my forks be revalved for my weight? Will i need to buy a different spring for the rear shock?

Is the YZ Seat/tank worth the money?

Any input is appreciated.


  • Mrmonk7663

Posted July 20, 2008 - 10:42 AM


You can revalve yes. A different rear spring weight will help also as the springs and forks come from the factory for a specific range of weight. Changing one and not the other will make your machine handle diffently than you desire....but you can do it. The YZ tank is only gallons, it is smaller and not as wide I believe.

  • maxtherat

Posted July 20, 2008 - 11:27 AM


My .02 about your questions:
1) Yes, the cam swap is well worth the money. if you have limited experience w/ this stuff I'd suggest the hotcams for about 130ish.
2)FMF Q2 can be found on ebay at times. I recently noticed FMF lists a Q4 for that bike now. I have personally tried an exhaust from a 06 450 and it fit pretty well.
3)For your weight you will need to revalve and respring both front and rear. If you can find them cheaper you can use stock YZ springs with a revalve. This is well worth the money.It's the most noticable change you can make to your bike.
4)A yz tank will lower your capacity from 3.3 to 2 gal. If moneys no object i'd say get a clarke or IMS tank that require a yz seat. They do lower your center of gravity and allow you to move further forward on the seat.

Do all the free mods that you can. They are all worth the time. feel free to PM me if you have any specific questions.

  • 02WR426Cali

Posted July 20, 2008 - 11:37 AM


The auto decomp. cam is not neccessary. Yeah sure it might be nice but the other things are much more important. I would start with the free mods, then do your suspension. You don't have to respring the forks but it will help. I revavled my forks (by myself) and left the springs stock by the advice of my valve supplier. Then using his advice again, I revalved the shock (again by myself) and went to a stiffer spring. This setup works great for offroad riding. I don't ride track or do any big jumps, but obviously there are big woops off road and I can cruise through them in 5 gear if I wanted to. If you don't revalve then I would suggest stiffer springs front and rear. I also have a yz seat/ tank. It is only 2 gal. but it is so much better. I have never even had to put it on reserve and I've done 50+ mile loops before. After that I would do exhaust and anything else you might want.

  • Birdy426

Posted July 20, 2008 - 10:46 PM


My 426 already had ESP suspension on it when I bought it, so I can't tell how much of an improvement it was over far as the other stuff, for me, the 3.4 gal IMS YZ tank and seat was the second best mod (after the free mods). With the 3.4 gal tank, you can put 1 1/2 gal's in it to ride track (with a lower CG than stock YZ) or you can fill it to the top for off of both worlds, and it REALLY improves the ergos on the bike. Best mod (after the free mods) was far and away the Hot Cams intake and exhaust cams. The bike has a whole new personality, and while it isn't a necessity, the auto-decomp sure is nice when you are stopped on a hill, ned to bump start, etc.


Posted July 21, 2008 - 05:12 AM


FIRST Suspension you WILL NOT find a better investment

SECOND Free Mods

THIRD Auto Decomp (for me anyway since I've gotten into Hare Scrambles)

I'm running a YZ Exhaust with Pro Moto Billet end cap and USFS approved SA

  • sandfarmer

Posted July 21, 2008 - 07:37 PM


Perfect timing on this question (for me anyway)! I just came home with my 01 WR426 a few days ago and had some of the same questions. I haven't had it on the trail yet but just running a little around here I've decided it's going to bang the heck out of me on whoops and washboard type stuff. Suspension work looks to be in my future...

  • dustdogg

Posted July 21, 2008 - 08:46 PM


I bought my WR 426 new in 02'. So far it has been a great bike. Every year I try to make a few mods. I have done the Free mods, Clarke tank/ YZ seat, YZ pipe/JD jetting, BRP sub mount w/ Scotts stabilizer and just recently I had my suspension revalved by Precision Concepts. Each mod was definitely noticable. I really like the new suspension:thumbsup: . They did an awesome job setting up the suspension for my weight (180 lb) and riding (desert). The Scotts stabilizer is also a great mod, especially for sandy whoops out in the dez.

I did a lot of research before spending my money and so far I do not regret any changes I have made. I do think you will be happier with changes in suspension, stabilizer and tank/seat before you try to get more power out of the motor. If the 426 is uncorked, jetted correctly and well maintained it will be more than most riders could ever use.

I do think that the YZ seat/tank is worth the money for any WR 400/426. You can scoot much farther forward than the stocker which makes the bike handle and turn better. My replacement seat is actually an SDG seat which I found is much more comfortable than the Yamaha "brick" seat.

There are many riders who have also installed the YZ 450 cam in order to get the auto decomp. I have not bothered to do this yet and I'm not sure if I will. I have no problems starting is so I would rather spend my money on other things (gas). You will be able to decide for yourself if you get tired of the "drill" whether this would benefit you.

I hope this helps with your new bike. I have owned my bike for quite some time and it always serves me well. With proper maintanence you should have a great bike that you can rely on:ride: .

  • Thumper_Bloke

Posted July 21, 2008 - 08:55 PM


You will love the auto decomp cam from the YZ, its a cheap mod and starts practically with the weight of your foot.

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  • yamazuki10

Posted July 22, 2008 - 04:49 AM


You will love the auto decomp cam from the YZ, its a cheap mod and starts practically with the weight of your foot.

Where can I get an auto decomp? Is there a preferred brand? How much skill is required to install one? Thanks

  • 02WR426Cali

Posted July 22, 2008 - 06:19 AM


Where can I get an auto decomp? Is there a preferred brand? How much skill is required to install one? Thanks

get one from an 03 yz450 from the thumpertalk store. an oem 03 yz450 that is. I think other years will work as well but most use the 03. search the forum and you will find a ton of info on where people bought it and how to install.


Posted July 22, 2008 - 07:38 AM


OEM from TT Store YZ OR WR either will work. I used the WR.

  • 02WR426Cali

Posted July 22, 2008 - 07:35 PM


Yes either will work but if you want yz timing you need the yz cam. If you want wr timing then you need the wr cam. It's not like the stock cam where you can switch back and forth. Well actually you can but you will lose the auto decomp.

  • ljparton

Posted July 22, 2008 - 08:44 PM


thanks for all the input.

I am going to do the suspension first, then the plastics, and YZ/tank Seat, and then the auto decomp and exhaust system.


Posted July 23, 2008 - 07:34 AM


I'd saveteh plastics till last. The don;t add anything practical as long as they're not broken.

  • 02WR426Cali

Posted July 23, 2008 - 12:05 PM


Yeah definitely get the seat/ tank combo and exhaust/ jetting before you get new plasitcs

  • creeky

Posted July 23, 2008 - 06:22 PM


For my money, the auto decomp is not worth it. My WR400 starts 1-2 kicks cold, 1st kick hot with proper use of the manual decomp, I don't even have to raise my butt off the seat. I'm totally on the same page with the others on getting the suspension done for your weight and type of riding, best cash you will spend on the bike period.

  • 2in2out

Posted July 23, 2009 - 10:19 AM


Yes either will work but if you want yz timing you need the yz cam. If you want wr timing then you need the wr cam. It's not like the stock cam where you can switch back and forth. Well actually you can but you will lose the auto decomp.

Which cam is suggested for the grey wire mod? Since doing this changes the mapping to YZ, would the 03 YZ cam work best, or is there a significant difference between the WR/YZ cam with the grey wire mod?

  • byggd

Posted July 23, 2009 - 12:34 PM


Where can I get an auto decomp? Is there a preferred brand? How much skill is required to install one? Thanks

Here are the instructions, cam part number and data from adding the 03 ex cam. I found the best price from the TT OEM store. Really wakes the bike up!! It's not too hard to install, just take your time. It does require a inch/lb torque wrench and you will need to re-shim while doing the install.
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