Derestricting WR450

hi can anyone help pretty new to the dirt just bought a wr450f 07 and would like to derestrict it.i have read a few bits with not to much making much looking for help from someone that knows exactly what to do in detail,so that i dont get anything wrong.i want to put a fmf q4 ti and need to know about rejetting.and i understand ther are a few things that i can do to get the max from the bike.i come cap in hand as the new boy and look forward to any help i can get thanks...

This site and the WR forum in particular has extensive information on the subject. I'm going through the same process. Check out the 'Sticky notes' at the top of the WR forum, has a long list of modification resources. Removing the grey wire, changing the throttle stop screw (from WR to YZ screw), removing the AIS unit (I'm not sure this is necessary really), removing the exhaust baffle, 'opening up' the airbox and re-jetting the carb. It's all there.

Do a search on the grey wire, throttle stop or re-jetting and you'll find pics to help.

Another resource is youtube. Search for dirtbikevids. this guy has done 6 great videos on WR modification and maintenance. Helps to see it.

I've only begun the process. Removed the grey wire, changed the throttle stop screw and now have much more power on-tap. The forum has lots of re-jetting info to be found as well - refer to the stickies - they'll get you started. :thumbsup:


thanks very much for your help that should give me something to get on with

You will need to do a little research on this site to hopefully find what jetting will work well for your area and altitude. I just got done with this process on an '08 and have yet to ride the bike so just hoping the jetting is close. This is certainly not a bike you want to have to rejet over and over as I have yet to see a bike designed as compactly in the engine bay as this one. There is not an ounce of space wasted anywhere. So take your time, and begin with a clear head. How people are able to work on the carb w/o removing the shock is almost unbelievable. I would remove it and give yourself every advantage you can. You will still wish you had hands the size of a spider monkey to do the work in there. :thumbsup:

I would think the AIS removal does something......I mean even yamaha sells a kit to run w/o it.

I would think the AIS removal does something......I mean even yamaha sells a kit to run w/o it.

I think for the most part, the benefit of the AIS removal kit is to make it easier to jet properly and keep the bike from backfiring on decel. Keep in mind that the Yamaha AIS removal kit is more of a combo AIS/rejet kit. Yamaha also realizes the bikes run like crap as delivered from the factory.

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