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DeltaT

04 wr450: Did the 2nd round of mods - What Next?

10 posts in this topic

OK, got an '04 WR450 and right away did most of the free engine mods posted on this site the same day I bought it. First day: YZ throttle stop, PMB insert (stock), grey wire, airbox cutouts on right side, White Bros air filter, dropped forks to the 2nd line. Took me 6 months, after a 22-year break in any type of riding, to start riding the WR at the level where I could start seeing deficiencies in the stock setup. Until I went to the 2nd level mods, I never even change the sag from stock. The front tire was truly evil, no matter what I changed.

I have not changed the airbox snorkle. Is the snorkle that important to remove? Does the mod add HP or torque?

I just did the 2nd round of mods: Screen removed on intake, JD jetting kit, 52-tooth rear sprocket, 5.8Kg spring in rear, with correct sag. The most effective mods so far were the tires (Michelin S-12 front (21") and rear (140/80-18)) and the new rear 5.8Kg Race Tech spring. Changing the spring and adjusting the sag to my actual riding weight (including gear and fannypack) was crucial to getting the bike to a reasonable geometry. I used to squat any time I gave it gas, and low-side a lot - (softest way to fall for for crashes but very annoying and can still bust you up) like 3 times per day. I also increased the shock rebound and decreased the shock low-speed compression damping to deal with the spring change (as recommended). I enjoy the 52-tooth sprocket, because it makes 2nd and 3rd a lot more useful every ride. Combined with the other changes, the 52 allows me to ride a gear higher than before.

I am running the PMB insert with stock exhaust system. The PMB is modified - I drilled out exactly the number of holes in the tip to bring the DB to 95.5, pass the 96Db CA test and get my sticker. It is substantially louder than my GYTR insert, but yields more power with the mods listed above. I slip the GYTR in if it is an especially muddy day, for more torque.

What do you think is next for mods, and how much will they affect my riding?

I do have Yamaha shims for the front fork spring, but haven't put them in yet. Would 2 shims in each side make a difference? How about the fork oil and weight? What are your preferred setting for the front forks and rear shocks (compared to the manual)? I don't believe I've bottomed out the forks the way they are now. I am trying to minimize the effects of stutter or braking bumps, since we have a lot of them in NorCal. Any suggestions? I currently have the forks set on 1 click less than stock on both compression and rebound. Seem reasonable?

Last question is regarding the JD Jetting. After installing the kit as per the instructions (#170 main jet, blue needle on 4th position, pilot screw 1 3/4 out) I notice a stumble in the lowest quarter of the throttle turn. Any ideas as to how to remove this?? If I mod the snorkel will it affect this? I need to keep at least the PMB insert for noise control - they check on weekends here in Hollister, CA. It's a big fine if you are caught.

All suggestions welcome.

Thanks,

Jim

:)

Jim

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hey jim. I have an 04 and I heard that the stumble can be resolved by using a #40 leak jet. If that dosent resolve your problem try looking up the BK mod. TT member Indy really knows his stuff when it comes to jetting our bikes, so look for posts by him or pm him. :)

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Send your forks out to get revalved. The WR stock forks have the worst harshness midstroke. :)

JD jetting kit is good but you may want to try a 48 pilot and the red needle in clip #5 . Blue needle works better with the air box punched with holes or modified to allow easier air flow and an aftermarket pipe. :)

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G'day Indy I'm not trying to be a smartarse but do you work, you always seem to be around answering Q's, If you do work I want a job like your's :)

mmmm then again I seem to be reading the Q's all the time to,pity I can't answer most of them :)

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G'day Indy I'm not trying to be a smartarse but do you work, you always seem to be around answering Q's, If you do work I want a job like your's :)

I come to the conclusion he doesnt. I figure he has a "sugar mamma" taking care of him and he is a full time off road rider. With the miles he puts on every week, he doesnt have time for work! And any time that is free, he is servicing the bike. What a racket he has! :)

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You guys are killing me. :) Just cause I can work from anywhere with a laptop and internet connection means I can be riding in Arizona and working early mornings and evenings and ride all afternoon. Divorced with no kids makes riding my number one priority! :p I have ridden in 21 states so far. Australlia sounds so cool. :) Where do you ride down there Greg?

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You guys are killing me. :p Just cause I can work from anywhere with a laptop and internet connection means I can be riding in Arizona and working early mornings and evenings and ride all afternoon. Divorced with no kids makes riding my number one priority! :) I have ridden in 21 states so far. Australlia sounds so cool. :D Where do you ride down there Greg?

Good luck to you Indy, I live and ride 2 hours south of Sydney,in what is mostly open trails and some tight snotty stuff, only been riding for 5 months but getting better with each ride(I hope) and ride every weekend and some days throughout the week. :)

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I am going to have to rent a dual sport and go have fun down under for a couple of weeks. :) We seem to have quite a few TT members from Australia. :)

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