how do I get the most from my new wr426f

I just put a brand new wr426f in my garage.I put my kdx200 away and im going smokless.I have freinds with mild four strokes,but none with a wr.Im sure theres plenty to be done to make this bike perform its best,but im an old two stroker and unsure of what to do with my new bike (accept to ride the wheels off it).Im hopeing that some seasoned wr riders can give me some advise on what to do to this bike.

Welcome to the world of smoke free.... There are several mods you can do to it to make it perform better. Do a search in this forum and you will find enough reading to keep you up for a week. The first thing I done to mine was cut the throtle stop, removed the air box lid, take the spark arrester out (pending on where you ride), grey wire mod, the BK mod (have not done this one yet), and YZ timing (not done to mine yet) just to name a few. If you do a search on each of these items you will be able to find all the information that you will need to know. Keep in mind that you will have to rejet after doing some of these mods. The posts should tell you when to think about rejetting, oh yea check out the jetting q's also for that hidden power.

All is great until Ol blue breaks

Welcome to the club, scrub.

I'm almost a poet. LOL

Give your bike a good break in, change the oil straight up, perform your free mods and rip it up!

Cut throttle stop to 23mm, lose the baffle and the airbox lid, cut or remove your grey wire from the connector.

Some folks say that cutting the blue wire is another good mod, I read stuff both ways on that mod and never did it.

I did the BK for the price of a sixpack.

I've yet to do the YZ timing or the jetting and my bikes pull hard and seem to have reasonably acceptable jetting.

Being at sea level probably helps.

If you like big heavy metal motorcycles, your gonna love this bike.

Congrats on your new mean machine. :D I've used quit a few 2 strokes and never was never tempted to go 4 because of the lack of responsivness from the engine. Now it's a thing of the past. :)

I just did the same thing, a brand new 426 is in the garage. :D There are lots of ways to improve this bike. But right now, I feel that I'll have enough of anything for a while, even in stock form.

Have a good ride :D

After you do the free mods the others talked about, get an after-market gas tank. IMS or Clarke make units that will let the bike feel like a dirt bike instead of a tank. Your gonads will love you for it. I paid about $250 for the Clarke unit with an SDG seat.


I did the same as you did, sold the KDX200 and bought a WR426F 2001. I have to say that I'm totally with Sylvain on that one. Take the time to get used to your bike. There is a lot to discover even if it is still stock. Anyway, it is already much more powerfull than your kdx200 was...

Mine is still stock except for the baja design street legal lightning kit, new jetting and air filter lid removed, and as I don't race, I'm planning to keep it like this for a little while at least.


Congrats on your new ride & welcome to the world of valves. Take your time & break that thing in. Once that's done, start with all the free mods. Unplug the pipe, take the lid off the airbox, cut the throtle stop and grey wire, and if you want do the YZ timing. Also heard alot about the BK mod too, just haven't done that one yet. If you do all of this at once you'll think your on a totally different bike. I don't know what your elevation is, but rejetting will most certainly be needed. Probably just a main & pilot at first to see how you like it. Up about 2 sizes on the main & one on the pilot is what mine took. From there you can start with the after market goodies. A stabilizer is probably the best for one to do. Scotts is the best known, but GPR and WER are also good & a tad less expensive. From there I'd look at a remote hot start button. The button is a pain on a side hill where balance is key to get going again. And at a race with dead engine starts, the hot-start is the key to a getting off the line up front. I like the Dr. D hot start more than the terry-cable one. I had the terry cable & didn't think it worked as well as the Dr. D. Also a pipe depending on how you like the power delivery of your new ride. My Thunder Alley feels very simular to the stocker from mid to top. The gains were all down low. The low to mid power jumped a ton with the new pipe and never pulled even close to it with the stock pipe. Even with all of the gains down low the bike still hits 90+ mph WFO in 5th. Problem is that it's not any quieter than the stock "uncorked" pipe. Still runnin about 100db's. If you want more top end power, the Dr. D and FMF Power Core worked well. If you want something quieter, the FMF-Q will keep it quiet but won't do much for power gains. You can also get the FMF Power Core & buy the Q insert as an option later if you don't like the noise.

Anyway, good luck with the new ride and have fun. You'll love how it'll leave all your two-smoke buddies choking on your dust. They'll never keep up.

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