from mild to WILD

To those all knowledgable enthusiasts at the WR forum. Thank You Thank You Thank You

I bought myself a christmas gift- new 01 WR426FN.

Broke it in easy- no more than 1/2 throttle for first 100 miles (turns out it's really 1/4 open).

Changed oil & filter-(filthy w/metal but expected)

Second 100 miles- still taking it easy, remove pipe baffle, occasionally 3/4 to full throttle (turns out it's 3/8 to 1/2 open). VERY SLOW BIKE.

I become totally hacked off at myself for letting the magazines encourage me to buy a JAPANESE 4-stroke.

Search the web for WR426F modifications last weekend and stumbled across

Directed by members to simple mods in the search.

Changed the oil & filter (still filthy w/metal).

Perform grey wire cut,air box cover removal, and cut throttle stop to 23mm last night. Today I go home early to ride after work this afternoon.


I still have questions about this bike.

1 - Will the BK carb mod and the YZ timing make as much a difference as these first mods.(freemod)

2 - Should I expect a noticable increase with an aftermarket pipe and muffler. (priceymod)

3 - Which dualsport conversion is better Baja-

Designs or E-Line.

4 - Does anyone have a set of wheels, front and rear, for sale. I'd like to have a set for street legal tires once it's streetlegal. Stock preferred or aftermarket if in good shape and the price is right.

Thanks again for the lowbudget mods you gave me.

[ February 01, 2002: Message edited by: Bill ]

Glad you like the old girl, Honestly, I havent done any more mods than you have already mentioned you did. I rode the bike all last year and I think the only other thing I am gonna do is the APJ TAFFY version. I also have the dubach hot start system and that is a must have.



I bought the E-line system. Hopefully I'll have pictures once the kit is on. I like the E-line since the blinkers are molded into the headlight and taillight assemblies. The only thing I found odd was on the headlight. The number plate above it is yellow not white like everything else on the bike. I called E-line and they said they will replace it once the get the white plates in.


'02 WR426


My buddy has a 2001 WR that started out stone stock...horrible where as my throttle stop and YZ timing was done on my 400 prior to the first ride. This site has provided the necessary tips to transform the 426 into something truely amazing, and both of us were used to open class two strokes. Pipe and YZ timing will compliment what you've started. The pipe (e-series w/ 12 disks) and yz timing has enabled this bike to rev much quicker and pull much harder. Have not done the BK mod yet...would like some advise from the experts.


You ain't seen nothin' yet!

Do the BK mod. Makes a huge difference in response when whacking the throttle open. No more bog...

Decide on a pipe or just uncork her.

Decide on the timing...YZ vs. WR. There's folks in both camps regarding which is better for their riding style. Personally, I havent played with it yet to make a choice either way, but that's only because my garage is 20F right now and there's white stuff on the ground.

Do searches on jetting and get someone's specs from your neck of the woods as a starting point. Regardless of timing, I recommend an "E" series jet as opposed to your stock "D" series. Just switching to the appropriate E series will make a big difference. "Yamakaze" raves about his jetting setup (taken from Taffy's advice)...and he's from Georgia if I'm not mistaken. If that's close to the same altitude/temp, perhaps start there and make a go at it.

All in all, regardless of what you decide, there's definitely a HUGE difference in how this bike is delivered to you and what you can turn it into. If you have the time and energy to do a little question asking and research, properly jetting the bike will bring out the serious potential in her.


here's my .02 for what it's worth.

Look at my mods on my little bio. That will save alot typing for me.The YZ timing made HUGE difference it is unbelievable how much more power. My buddy too has just picked up an 02 WR 426. He's put the same YZ pipe as I have BUT he did not do the YZ timing. He got very little improvement in power just more noise, Bottom end was a little crisper. We messed with jetting and came full circle, almost back to stock. Final results were stock jets and needle raised by 1. I might be wrong and I'm sure others will disagree,.But it seems unless you go to YZ timing you won't get the full benefit of your $$ on a new pipe. It would be interesting to see how a YZ timed bike does with stock exhaust. By he way, in our opinion the un-corked WR pipe was louder than stock YZ pipe..


Yo SoCal and Husky,

I agree with your assessment SoCal on the pipes and YZ timing. The only pipe that I've heard about that people didnt have varying opinions on was that one discussed about 2 months ago...some very small shop (an individual I think) that was hand-crafting them out of his garage. He was advertising them at the local tracks out west I think. Other than that one, I've formed the opinion that the gains in performance are minimal...although there's probably ones out there where you dont lose much from the uncorked stock WR pipe or YZ pipe and get reductions in noise.

Just so you know, my buddy has a YZ timed, uncorked stock WR pipe, stock jetted bike and his just flat rips in the midrange...although a little weaker on the low end. Mine's a WR timed, uncorked stock WR pipe bike with the BK mod and YZ jetting (see jetting setup below). My bike is definitely more torquey in the low end (due probably to the jetting, WR timing, and BK mod)...but lacks his midrange punch. I can say that my bike's a heck of a lot stronger (midrange) with the Exx needle vs. the stock Dxx needle...

The jury's still out on the choice of WR vs. YZ timing based on throttle response (there's a thead out there right now on this topic), so choose and go with one or the other. Bottom line...the stock jetting on my bike with the Dxx needle wasnt very good out here in CO...and the change to the Exx needle was very significant...not to mention the improvement based on the BK mod. You may find that the stock jetting is better suited to your locale...but it wasnt out here. Definitely do the BK mod at the very minimum...


[ February 01, 2002: Message edited by: LarryCO ]

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now