The "Mysterious Grey Wire"

[DirtDobber]

I just got back from the Florida Suncoast Hare Scramble in Polk City, FL. They had the beginner, Vintage, PeeWee classes running today. The rest of the classes will run Sunday 11th (tomorrow). Anyway, I met a rider from north Florida that was riding a WR450 2003. He had cut the grey wire further down the frame (where it is blue instead of grey). He had a metal gator clip attached to one side and the other side was stripped back to allow the clip to reconnect the circuit back.

He said it really made a big difference with it cut on top end, and if he was doing a lot of slow technical riding he would reconnect it back for more low end torque.

My question is this: If I were to put a rocker switch on the handle bars that would do the same thing (WR-YZ) could I use the switch while the engine is running without causing an electrical problem? I don't want to fry the brain box or any electronics. I really think this would look cool with the switch labeled "WR" - "YZ" mode.

Any thoughts? ?

Thanks.

DD

[tctrailrider]

Dirt,

You can inslall a switch as others have, but you can't go back and forth while riding. You need to shut it off, switch, and then restart. The gray wire is a ground. Connected it retards ignition timing (WR) and disconnected is YZF timing.

[DirtDobber]

Thanks TC for your response. Sounds like it would damage the circuitry to switch while it's hot. With this in mind, it might be good to use an aviation toggle switch that has a manual lockout feature to avoid accidental activation.

DD

[Rip Wheeler]

I have the grey wire hooked via a switch to runit in WR specs or YZ if I need. I have switched it while its ben running with no problems. Not sure if the change happens then, or when its shut off.

[DirtDobber]

Toy,

Thanks for your input. Looks like from your experience, the electronics won't "self destruct"

But you might have a point about it not taking effect until it is shut down. Hmmmm..... the way the guy was talking yesterday he could tell a BIG difference between the two modes. But if you can't really tell when you switch, it makes me wonder if it's worth it or not.

It would be really neat to have a dyno report on both modes. I guess that would tell the tale.

Keep the comments coming guys, if you've made the grey wire cut, could you tell the difference?

Thanks,

DD ?

[CoalPilot]

Couldn't you hit the kill switch (till it shut off) flip your wr-yz switch then pop the clutch and your back in business? The whole procedure doesn't take that long but I wouldn't do it while racing. And I know some bikes don't like to be 'pop' started so just use the happy button.

It would appear to me that the engine does not need to be actually stopped but the electrical needs to be shut off, so when its turned back on after the switch is made, the signals are rerouted for the other timing.

What if you have a momentary switch that cuts the power to the brain (not just the spark plug)..push it in then switch your mode (wr-yz) and release the the momentary? That can be done very quickly without having to actually stop the motor dead and restart.

Just my thoughts. I'm here to learn like everyone else.

[WR450F_RDR]

You could do as I did DirtDobber and just pull the pin on the grey wire in the harness connector that way if you are not satisfied with output you can just plug it back in. When I first recieved my WR I pulled the pin on the grey wire and have not ever put it back in, I saw good results of it.

[tctrailrider]

the way the guy was talking yesterday he could tell a BIG difference between the two modes. But if you can't really tell when you switch, it makes me wonder if it's worth it or not.

You will get differing opinions on this one. Some love it and many can't tell the difference. My opinion is that the closer you make your bike to YZF specs the more difference it will have. Exhaust is a big issue. Free flowing and loud it will help, quiet and restricted it won't do much, maybe nothing at all. ?

[DirtDobber]

You will get differing opinions on this one. Some love it and many can't tell the difference. My opinion is that the closer you make your bike to YZF specs the more difference it will have. Exhaust is a big issue. Free flowing and loud it will help, quiet and restricted it won't do much, maybe nothing at all.

You know at this point guys, I think I'm going to just leave it be for now. If my riding ability gets good enough where it needs just a tickle of more power to get ahead in a race, then maybe it will be worth it. And for me that will be a long ways down the trails!

As I watched the AA class run today, some of those guys riding ability could make a TTR 125 look awesome! ?

Thanks for all the input!

DD

[westrider03]

I've cut the grey wire on my 99. It doesn't make the power uncontrollabe like a super rocket or anything like that, it just gives it a bit more hit from midrange on up.

-Cameron

[5spoke]

I met a rider from north Florida that was riding a WR450 2003. He had cut the grey wire further down the frame (where it is blue instead of grey). He had a metal gator clip attached to one side and the other side was stripped back to allow the clip to reconnect the circuit back.

He said it really made a big difference with it cut on top end, and if he was doing a lot of slow technical riding he would reconnect it back for more low end torque.

My question is this: If I were to put a rocker switch on the handle bars that would do the same thing (WR-YZ) could I use the switch while the engine is running without causing an electrical problem? I don't want to fry the brain box or any electronics. I really think this would look cool with the switch labeled "WR" - "YZ" mode.

Any thoughts? ?

Thanks.

DD

The mod is for the grey wire only. If you look at the circuit diagram the grey wire joins a black wire from the CDI before it goes to ground. If you cut the wire 'further down the frame,' you might be cutting the ground wire for the CDI as well. I just pulled the pin out the connector and put some heat shrink around it.

[MN_Kevin]

If you go aftermarket black box (like my Vortex), there will be no gray wire.

A few years ago, someone dyno'd their bike w/ this wire removed (a before AND after dyno chart). The difference WAS EXTREMELY astounding! Cutting the wire also cured up a midrange stumble.

Don't forget the silly neutral switch wire as well. Cutting that (or using Ty Davis Neutral Switch replacement plug) has been said to improve spark for starting purposes.

I have done both mods to my 99 WR420 Big Bore.

[DirtDobber]

Thanks for sharing the pic! Nothing like a good photo to "clear the air". I like the idea of just pulling the socket/grey wire from the plug and heat shrinking it. Looks professional. I'm glad I started this thread, it sure has helped me and hopefully others here too! Thanks for all the input guys!

DD ?

[wrooster]

some more info, some more pics:

http://www.thumperfaq.com/gray_wire.htm

and some 250F dyno charts, w/ and w/o grey wire plugged in:

http://www.thumperfaq.com/gray_wire2.htm

jim aka the wrooster

'01 wr250f

[DirtDobber]

Ok, only I could mess something up this simple! ?

I pulled the connection plug apart to remove the grey wire. I pushed the connector from the inside of the plug out with a very small screwdriver. Slipped a piece of silicone fuel tubing over the grey connector and reassembled the tank and seat. When I pushed the ignition button the red light didn't come on, the bike was dead. So in a panic I pulled the tank and seat back off, and replaced the wire back, but still no go. I was heart broken. I couldn't even take care of a simple wire removal without messing something up!

Well, I broke out the manual and started going down the check list. I checked the battery, it was fine. Then I checked the fuse.... BLOWN! Evidently during the disconnect or wire removal, I popped the fuse! If I had half a brain, I would have disconnected the battery first BEFORE messing with the wiring! Anyway, Yamaha puts a spare fuse in the holder for idiots like me. Swap them out and everything worked fine! Phew! So, this time with fuse removed, I redid the grey removal again, then put the fuse back in! It started right up!

I haven't had a chance to ride it any yet, but will let ya'll know if I can tell any difference.

So bewarned, pull the main fuse BEFORE messing with the wiring! This fuse is a ten amp, I didn't hear any pop or see any spark during the wiring operation. I think just pulling the plug apart blew the fuse.

At any rate, once again, I lucked up! Now all I have to do is to remember to put another spare fuse back into the holder for the next wiring excursion! Will I ever learn?

DD

[5spoke]

Was the ignition on while you were doing the mod? I'm looking at the circuit diagram and I can't see how the cdi could have any power on it without the ign. being on. It looks to me that there would have to be a short in the rec/reg or the ign. would have to be on for the fuse to blow. Let us know, as a 10A+ short is serious.

[DirtDobber]

No, the ignition was off. I did check that before I started to work on it. I seriously do not know how I blew the fuse, but I did! ?

DD