'04 WR450F Gray Wire Mod - Bogus?

YamahaSteve, I have an 04WR450 and ride at the same altitude (4700' in Utah),

I was noticing your jetting settings in your signature. Do you have it piped also or just unplugged? Concerning the grey wire, is there a time when you think it's better to have the WR timing? Like making it easier to start or a type of terrain that you would want slower timing?

My bike is just uncorked with stock header and stock can. I also pulled the snorkel in the airbox... that mod as far as I can tell did not change much for me. I jetted my bike a year ago and have forgotten most of what I did... but PM me or use the forum if you want any other jetting info...

As far as the timing goes... I would say no. You can always use more power... just don't turn the throttle so far is you need less :cry:... my WR still has great predictablity, meaning it has no hit... just pure smooth pull all the time... if the timing charts I were refferring to earlier were accurate (and I wish I could find them again) then the WR timing drops to zero degrees after 3 or 4 thousand RPM... this is not optimal... the YZ plot showed about 30+ degrees advance at 9k... the WR had 0 with the greay wire intact.... granted it was along time ago I saw these plaots, but I remember the zero advance aspect clearly. What that means with zero advance is that the piston hits TDC and starts downward at the same time the spark is ignited... when the engine is at high rpm the piston can outrun the flamefront which causes power loss... the advance starts the flamefront earlier so that it is pressing on the piston maximally as it starts is downward motion... my 2 cents.

edit: This has NOTHING to do with the valve/cam timing BTW... only spark advance.

Bushman06 what part of the Lone Star do you claim?? As for the Grey wire Pull it of the Harness , don't cut if you don't like the hit Reverse proceedure. Have fun

Here is the link to the difference between the grey wire connected and disconected on the wr250 I would believe it is relatively similar to the 450.


You will notice a definate drop off after about 7000 rpm's instead of pulling all the way up to the rev limiter like the yz does. I suggest that this mod definately be done!! I have converted 7 wr's to the yz. This mode has made a difference on every one of them. Just my opinion though.

I just helped friend convert his 05 wr450. He was not happy because his 04 wr250 would out run his 05 wr450. I pulled the grey wire out of the harness, opened up the airbox, cut the throttle stop, plugged off the AIS system and removed it, pulled the plug out of the pipe and put in a cam out of a yz450. The results were amazing compared to the stock bike. IMO they really detuned the 05 compared to the 03 and 04 I have had the pleasure of playing with. The only think left to do is loose the stock pipe and replace the silencer. The stock pipe is still very restrictive compared to the yz. He should have it in the next week or so. I will let you know how much difference it makes.

I did all the free mods on my 04 WR450 and I consistently outran guys on 2 smokes. Even my buddy that has a big bore kit on his YZ250. I left him like he was sitting still in a field section at the Loretta Lynn's GNCC! He couldn't believe how my bike took off. Do all the mods and uncork the exhaust and I think you'll be fine.

Hey mate,

I live in Dallas! How abouut yourself?



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