HEADS UP!!!

Site upgrade in progress... Core site functions are working, but some non-critical features/functions will be temporarily unavailable while we work to restore them over the next couple of weeks.

Please post any bugs you encounter, but before you do, check to see if it's already listed.

Thanks for your patience while we work to improve the community.

Sign in to follow this  
Followers 0
Highsider1

Grey wire

9 posts in this topic

I just joined up with ThumperTalk after reading posts for a couple of weeks. Purchased my first Thumper 1-1/2 months ago, a '02 WR426. Been a 2-stroker all my life (at least off-road) and decided to convert. Lovin' th WR and must say I am still learning the 4-stroke technique but now, after about 325 woods miles, it's coming together quite wonderfully. Oh, and the hill climbing attitude it has!! :) Will never return to the 2-stroke, except for "Novelty" only.

Anyway, question is: What are the wires you guys are disconnecting? I assume that one is a rev-limiter, what is the other? I uncorked the bike, the airbox, exhaust and throttle stop, and am happy with the R's I get now, but it does seem to hit some sort of limiter at high RPM. Is it really safe to rev much higher?

Any help is greatly appreciated. I already love the site/forum and hope I have some usefull input for you guys as well!

Oh, and by the way, I do recall reading on Yamaha web site that the WR450 is about 6 lbs lighter that the '02. The link was removed a while back.

Share this post


Link to post
Share on other sites

I am not POSITIVE, but I belive that the disconnection of the grey wire allows the bike to run off of a different CDI mapping, one that is smoother and allows the bike to run much better.

I have done this, and I found that my bike lost the stumble that I would get when I was bombing down the highway, seemed like the bike rolled on the power smoother, and it did not detriment the economy.

As for the wire, take off your tank, and look for a 2-wire black connector that has a black/w white wire and a grey wire. Disconnect that black connector, and pull the grey wire out from the back of the connector (I then pushed the grey wire up into the insulation) then reconnect the black connector.

That is all that is required.

\

Some cut the wire, but if you get the wrong one, well, then you get to work on your wire reconnection skills.

Brandon

Share this post


Link to post
Share on other sites

Search for "Grey Wire" mods and you will find all of the information you will need including clear pictures. Seemed to help my bike. If you only disconnect the grey wire, you will still have a rev limiter. Don't attempt to disable your rev limiter or you will probably be sorry. I can easily rev right into mine without trying too hard. Without it you will probably overrev sooner or later.

Share this post


Link to post
Share on other sites

Light blue wire, part of the six pack coming out of the CDI. This is a neutral line, that lowers the CDI output when in neutral. Some have reported better starting once disconnected, supposedly do to a better spark in neutral. I cut mine, and didn't notice any difference..........but my bikes alwasy started easily.

Dodger :):D

Share this post


Link to post
Share on other sites

Man for being least effective mod it sure gets the most attention. The grey wire is on the US WR bikes for emissions. It prevents the engine from emitting too much noise, thus being able to pass the feds sound test.

From what I’ve read, it helps the 250’s more than the 4xx’s. On my 02 I noticed a little better engine mid throttle control and that was all. Depending on how you’ve modified your bike you may feel more of a performance gain IMO.

It’s a very simple mod and won’t harm the engine in any way. Go for it!

Share this post


Link to post
Share on other sites

BTW WELCOME TO THUMPER TALK!!!

Highsider1, try the YZ timing and EMM needle… You’ll love it!

Share this post


Link to post
Share on other sites

I'm going to add a switch in-line so I can toggle back and forth between gray line and no gray line... Should give a good indication of whether or not it does anything.

Share this post


Link to post
Share on other sites

While you’re at, you might want to do the blue wire mod. It cuts down the spark intensity while you’re in neutral.

Do this mod if you are fouling plugs.

5.jpg

1.jpg

(((Thanks Motoman393 for the tech pics!)))

Share this post


Link to post
Share on other sites

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
Sign in to follow this  
Followers 0