Grey wire difference.

Hi there everyone, I have been giving my 02 wr426 a once over as it is new to me.

I checked valve clearance, ( all in spec ), & whilst in there checked valve timing, it is set to standard wr timing of thirteen pins between the cam marks.

Now mine has the grey wire disconnected, & my question is this, I do a lot of tight trail riding most of the time, & wondered if I connect the grey wire to a switch so I can use both maps, does the grey wire connected make the bike run smoother at low revs, or will there likely be very little difference?

Thank you for looking & any advice, I'm getting to love this bike!

I did not notice much difference at lower speeds so I don't think reconnecting will do much for trail riding. I did feel a little more punch at higher rpm.

I was going to wire a switch, but then after I pulled the wire an ran it I decided it would not be worth the effort.

Pulling the wire alters the turnover points (via tps) and advance by about 10+ %.

Once you get used to it you will most likely not find a reason to go back.

Just get better at throttle control and it won't matter.

UK (european) bikes are questionable on whether the grey wire mod actually does anything


My mates 250 2002 model and my 450 08 model do not seem to have any difference with the grey wire connected or not

Thank you for the replies, sounds like it is not worth fitting a switch, I will leave the grey wire disconnected.

As an ad on to this thread, my bike (426f), is according to my insurance, an import, (From where I know not)!

On checking it over I notice it has the yz throttle stop screw, the grey wire looks like it was disconnected as stock, & it has the original muffler on it, which has the non removable tip, (factory welded on). Airbox snorkel in place.

The bike is I believe completely stock in this form, my question is are there any modifications that anyone would advise me to undertake on this bike fuel/exhaust setup, as these euro bikes are it seems different in setup to the US bikes.

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