moddin my brand new wr450r '04 in oz

hey guys,

i have been reading for a while about all the mods and stuff to get the wr really moving, but i'm a bit confused???

to start, the australian version of the wr450 only has a tiny baffle in the exhaust with pop rivets holding it in. i have chiseled them off and removed a very small baffle from the end. most of the pics on the web seem to leave a much bigger hole after removing the baffle then mine???

next, my wr came with a racing sheet and a throttle stop screw also, but the initial screw was reducing the throttle to 50% i quickly changed the screw over to the one supplied which has given me more power, but i don't think it's a yz spec screw. do i need to go and buy one of these?

i also got a front counter spocket in the kit which has one less tooth on it, should i be installing this for performance gains.

i would imagine the grey wire makes a difference to my model also?

do i need to cut holes in my airbox because of the position of my battery?

sorry guys. i love my wr and need your help in making it even better!!!!



i also saw on another site about changing your exhaust cam over to the yz one. is this something i can do myself or am i better off getting someone else to do it?

something further :cry:

in the kit was also some extra jets for the carby, can i install these or should i get a jetting kit?

:cry: help pplz

Aussie models don't have to worry about the grey wire.

For better air flow you have to fabricate a cradle for the battery to sit in the top of the airbox.

The throttle stop in the race kit is all you need and use the largest(178?) main jet in the kit when you change or modify the std muffler, best muffler is the yz pipe.

Pull it apart and repack it well and the spread of power will be much smoother with a good hit in the mid-range to top-end and it's not noisy. :cry:

Best gearing I've found is 14/51 for all round use some go lower 14/52 but it's personal I suppose?

I wouldn't worry about the YZ cam if you jet it right and get the muffler sorted it should rip! :cry:

thanks for that.

just a couple of things. why don't you worry about the grey wire in aussie models? no difference?

why is the yz pipe better than aftermarkets? should i get yamaha to fit the jets when it goes in for valve clearances?

found anything on the web about fabricating a cradle for the battery to sit in (ie. diagrams?)

No grey wire for Oz. sounds like you are addicted to doing all the mods. Ride it! If you're not happy with it, mod it then. The YZ pipe is no better than an aftermarket pipe, just cheaper. I paid $AU200 for a mint YZ pipe on ebay and about $AU240 for a GYT-R header pipe which makes for a cheap system. Turned out to be a waste of time becuase it wasnt much quieter than the DSP factory pipe I had on there before, but did have heaps more midrange. Do the jetting when you change the pipe.

You can cut the arse out of the stock muffler and weld in a larger outlet. A friend of mine did that and his sounds better than stock, but quieter than YZ.

thanks for that,

i might just look at a zorst, jetting, adjusting airbox and sproket :cry:

cheers guys

I also have the 04 WR450 (AUS) and have performed most mods to it. What I have found is that putting on the yoshi exhaust and changing the jetting etc the performance is good but the low end hit is a little harsh for the hill climbing I do. Just ride it and see if you need to go down that track.

Airbox - Just cut out the two oval templates on the right hand side of the airbox

Grey wire - Not much difference

Jetting - Get the adjustable fuel screw to tweak the air / fuel mix for the conditions. Avail on this website. I also installed the JD jet kit. Also good.

The bike comes with a 15T sproket. I swapped to the 14T to gear the bike down and make 2nd more useable on the hills.

The throttle stop that comes taped to the paperwork is the same as the YZ stoppper.

Just ride the bike for a bit to get a baseline and if you like it dont worry too much about the mods.

Hope this helps

put on the 14 sprocket

pull off the right skid plate and cut out the cut outs i used a sharp knife

cut the grey wire. turn out fuel screw 2 1/2 turns

it will sound and go better.

where do i find the fuel screw :cry:

At the bottom of the carb. You will need to use a small cutdown screwdriver if you dont replace it with the zip-ty or similar. Only small changes (1 /4 turns) are needed to change the way the bike runs.

Here's some good links:

Also have a read of this article:

Also the manual is also a good bedtime read. Reading is the key :cry:

would stock position be best for most operating conditions?

im worried if i move it, it'll never be right again and i'll screw it hehe

Unless your at higher altitudes, you'll want it richer, most likely.....more than 2 turns out and you need a bigger pilot jet. More than 3 turns out and you'll lose the needle, oring, washer and spring...... :cry:

what are you looking for, for the best air/fuel mixture? am i listening for something? will i do damage if i run too rich or too lean? :cry:

If your bike stumbles off idle when the throttle is cracked-especially after you've been coasting off throttle-the fuel mixture screw setting is too rich. Turn the fuel mixture screw in. If the setting is too lean, the bike will hesitate, go "waaah" and have an airy feeling right off throttle. A bike that pops also hints at a lean pilot circuit. If your four-stroke pops at the crack of the throttle, suspect the fuel mixture adjustment but also check for an exhaust leak at the head pipe or slip fit.

This was taken from the article I posted earlier. I find that if the bike is bogs a bit I will lean the air / fuel mixture by screwing it in 1 / 4 turn. Sometimes at the start of the day I will jump on the bike and fiddle with it a bit until it runs great.

yeah i read that article actually. i am more concerned about damage to the bike if i dont notice anything wrong when there actually is. sorry for being daft! :-/

what are your guys thoughts on jetting. do you find the fuel mixture adjustment sufficient?

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