Grey wire mod on UK WR450s

My apologies for such a newbie question, but I have searched fairly far and wide and still don't have a definitive answer.

Does the grey wire mod apply to UK/Euro WR450s or just the US models?

Some people seem to advocate doing the grey wire mod on UK bikes, but looking in my UK 2007 WR handbook I can't see any mention of the mod. Mind you, I don't think it mentions the throttle stop either, but that certainly needs doing on UK models.

I've also heard people on other sites suggesting that the mod doesn't need doing because emission requirements are different between US and the EU.

A third school of thought seems to be that pre-2003 UK bikes didn't need the mods, but more recent UK bikes do need the grey wire removed.

If anyone could clear this up once and for all, I'd be really grateful.

(Also, on a tangent, can anyone tell me whether if I fit an FMF Q4 slip-on and open up the airbox if I'd need to fully rejet or just tinker with the fuel screw?)



Hi, uk bikes dont need the mods done as they are full power, US laws are different to ours due to emissions.

Hope this helps have fun riding:ride:

mine still scares the Crap out of me after 2 years!:lol:

Ive kept mine standard due to upsetting the locals so i cant comment on the pipe stuff sorry

On my 04 450 the throttle stop was already done but the grey wire mod hadnt been. My advice would be to whip off the fuel tank and have a look for youself. If you search youtube for the wr grey wire mod theres a great video showing exactly how to do it which realy helped me so maybe it will help you too.

Regards, Ross

dont need to do the wire. if you want more power get a jd jet kit and a full exhaust, this makes the uk bike a lot faster.


I had to do grey wire mod im in South Africa

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