grey wire on the wr 450,08 reg alloy frame

:banana::thumbsup:hi, ive been reading about the grey wire removal, i think ive fornd it on the left hand side behind the rear fender, ive found a six pin plug and in there is a grey wire, ive disconected it, is this the right one and what exacly does it do and also do i need to do anything else, on here it seems to be for older models, am i ok to do it with my 08 model,alloy frame, any help will be much appreciated, roooky to alll this mod stuff !! cheers :eek::thumbsup:


Yeah that's the one.

I believe its an earth wire and disconnection causes minor changes in the ignition advance curve.

There was an image of a (2009 WR450F from memory) before/after dyno run somewhere here in Thumpertalk a while back. The disconnection does make a difference to the power delivery, but its minor.

Apart from that, engine-wise, replace the pea-shooter in the end of the muffler with a better breathing one and re-jet if necessary.

I've also fitted a YZF header to my '08 and opened the stock muffler up. You can often find YZF exhausts real cheap on eBay.

The suspension is pretty average. The compression damping on the front end especially. Set you race-sag at both ends and look at re-valving as soon as you can.


I just bought an '08 450. It's not clear from the previous owner what mods have been done. The Power Bomb FMF pipe is obviously there, but who knows what free mods have been done. Looking at the left tail section the six wire loom has the grey wire intact. It's possible it was disconnected somewhere else. Is there an easy way to check if the grey wire has been disconnected or do I have to remove the gas tank, etc.? Thanks.

Can't see why you would disconnect the gray wire anywhere but behind the rear number plate. As mentioned you might not notice the difference either way. I disconnected mine before ever riding the bike so I couldn't say.

The difference actually was quite big when I disconnected grey wire. And you can find whether the grey wire mod is already done by measuring resistance between frame and grey wire. If the circuit is closed, then the mod is yet to be done, if not - your bike is already modded.

Hitman, Just had a peak in your garage and noticed you've got a 426?. I noticed it a heap more on my 426.

I've done the same mod to my 08 450 and I reckon the difference was only very minor for me, certainly not as much as on the 426. Might be showing my lack of feel for the motor here :thumbsup:

As WR450FGREG said, suspension is a must-do, especially if it's got a few miles on it and never been done, as the forks apparently get worse very quickly after a while from new - start blowing through their stroke even more quickly than when brand new.

I'm only going on what I've read here, as I sent mine off pretty much as soon as the bike was run-in.


the forks apparently get worse very quickly after a while from new - start blowing through their stroke even more quickly than when brand new.

Apparently the main issue with the stock Yamaha setup is that silly little spring in the valving that controls the compression damping. It "softens" with use and susequently the forks slowly lose compression damping effect.

I may well be shot down by the "experts" here, but that's what I've been told (and read) is the main problem with the forks' valving.


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