grey wire mod applicable to wr426 and wr400?

Got a quick question: Does the grey wire mod applicable to the 99/00 wr400 and 02 wr426? For those who have made the grey wire mod, did you notice a big difference?

Made a significant difference. My '02 runs like a raped ape now. Considering the Hotcam with auto-decomp for this winters tear-down and valves.

Got a quick question: Does the grey wire mod applicable to the 99/00 wr400 and 02 wr426? For those who have made the grey wire mod, did you notice a big difference?

yes, it applies to those bikes

It applies and makes a world of difference. I actually hooked up a switch that is sold in WPS for a KTM that allows to connect and disconnect on the fly. My bike had the wire disconnected when i bought and is jetted for it. but it is nice being able to switch it back and forth. I use the wr mode for knarly hill climbs then open it up on yz map for the high speed stuff.

Do you think there any harm in switching it back and forth like that?

It applies and makes a world of difference. I actually hooked up a switch that is sold in WPS for a KTM that allows to connect and disconnect on the fly. My bike had the wire disconnected when i bought and is jetted for it. but it is nice being able to switch it back and forth. I use the wr mode for knarly hill climbs then open it up on yz map for the high speed stuff.

What advantage does the WR timing give you on gnarly stuff?

The low end grunt of the WR map. What you are doing is changing the ramp up of the ignition. The YZ has more of a roll on feel and the WR is basically right now torque.

I hooked it up hoping that it would work the way it thought it would. I riding the first time and really couldn't tell the difference but then I did a 53 mile poker run and I could tell it made a huge difference. I had it in WR mode to begin with because some of the trails were pretty bad at the beginning with some new trail section that required a lot tree dodging. Well when i got tired of being ripped back everytime I hit the throttle I switched it to the YZ just to see and that was much nicer. I could roll on it and was not as aggressive at low rpm so it was easier to hold on and control the throttle.

The time it really shined was a 3 foot root in the middle of an up hill that my friend crashed in front of me on so I had to stop and help him. Then i had start on the hill and go up the bank and around it. I tried in YZ and I had to bring the r's up and dump it and almost went over. So I switched it and was able to just let the engine lug and pull me up and around.

Oh and for the running issue. From what I understand when you do the Grey wire mod you have to jet it for it. I was told you go bigger jets so switching to WR you would be running richer if anything. Which is not as bad as running lean.

I have a Trail tech Vapor on my bike and the engine ran fine and the temp stayed consistent in either mode so defenitly no heating up was a result.

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