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De-restricting WR450F

Discussion in 'Technical and Troubleshooting Torque' started by Browncoat, Jun 25, 2011.

  1. I just got myself a 2008 WR450F and i've been reading about all these compliance restrictors that have been put in place on them, such as a plug in the exhaust and throttle restrictions, and a mysterious "grey wire" that can be taken out of the cdi loom which changes the ignition map from WR to YZ.

    Now I know for certain that the air box snorkel has been removed and the exhaust plug has been taken out but i'm not sure what to look for with the carb. anyone offer any assistance along these lines??

    I've actually got a yoshimura pipe coming in a couple of days, am I going to need to re-jet after fitting?

    Its a nice bike bike just seems to be lacking a little bit of low down power.
  2. check where the throttle is attached to the carby, it may have a tab that is designed to limit the throttle movement, ie it will only open to 50% 60% etc not 100%. im not sure about this bike but that is something that is known to be done to limit the throttle.
  3. you will need to rejet most likely. is it a full system or slip on? you can actually get a jetting kit specific to the bike, or just go onto the thumpertalk forum as they know everything about these things.

    i would nearly be betting that the grey wire mod and the carb restrictor has been removed. if you can twist the throttle more than about stuff all then it would be done.

    if you want to take a look, you need to do this. go to where the throttle cables go into the carby. there will be a big plate on the side (has keihn written on it) with a couple of allen head bolts on it. take it off. you will now see something like this.


    that screw that the arrow points to is the one that limits the throttle. from memory, to be cut down correctly it will have to be about 22mm long or something very close. the screw still has to be in there, as the slide can bottom out creating excessive wear.

    grey wire mod is simply disconnecting the grey wire from the clear plug from the cdi. if you take your tank off, you should be able to find the wires that come from the cdi. there will be a 6 pin connector (clear in colour) that will have a grey wire running to it. you can simply cut it or pull it out from the switch so it can be connected up if need be.
  4. awesome! thanks guys.

    JimmyD is picture of a WR? I've been told the carby restrictor is a circlip with 5 different positions?

    Also do you know for sure if the grey wire mod applies to 08WR450F (aussie models)?

  5. yeah thats a WR, just the eariler model with the steel frame. i thought the carby would be pretty similar. if not exactly the same.

    yeah grey wire mod is still there. i did it on my 06 450f and my 03 250f. i have a mate with an 08 and i think he did his too.
  6. Ok great, thanks for the info mate.

    I'll post back later after i've sussed the carby on my 08.