1999 YZ400F fly wheel weight.....lighting coil

Hi there, Im new to this forum I ride a 99 YZ400F i bought it stock in july03 ive only been out trail riding(alot) on it and done a few enduro races with it(fell in love with those).......for now ive got a 12V battery mounted to the triple clamp with a switch running a WR headlight that i can charge back up when it runs out(is not very bright but passes inpection for the enduro races)...my YZ is street plated as well.....after riding this bike ALOT through july til now and also riding my friends 2000 WR400F Iv decided i really need to modify my YZ to run more like the WR400....i LOVE my YZ and its seems noticeably lighter and smaller than the WR400 and thats why i want to keep the YZ and modify it.........i thought about getting the new WR250 but tried it out and don't want to part with my YZ400 power ......so i came on here and was reading about fly wheel weights, sprockets and also about lighting coils for better lighting.

the only riding i do is trail racing....i run enduros and will also might try a hare scramble or two this season....i LOVE the really tight single track and find the gearing on the WR waaaaaaay better for that........i want to make my YZ more like the WR in terms of gearing and was wondering what i need to do.........from what ive read i need a heavier fly wheel(what weight would you suggest??) and maybe even a larger rear sprocket?? stock is 49 teeth....what about the front sprocket, stock is 14???

thanx for any help.......

Tammie---Girl in Canada on 1999 YZ400F :)

Hello again Tammie

You can install a wr stator and flywheel on the yz400. www.Electrex.com sells them for $300. The stator puts out 130 watts and the heavier wr flywheel is great offroad.

The stator has to be modified to work with the yz cdi The electrex one is already modified.

YOu can save a few dollers and but the stator and flywheel from Yamaha and do the mod yourself. Electrex has a link on there site that shows you how to do it.

Running a 13t front sprocket in the woods works great.

If you havent done so yet install handguards.

Something that you are going to find out really quick is that thee yz400 heats up real quick in tight nasty single track. I have overheated mine so many times I have lost count. YZ's wern't designed to run slow. THe radiators are smaller than a wr's.

So to solve all these problems I am getting a WR250 this spring. I can hardly wait.

If the Wr you ride is stock then you missed out. With just a few mods they really sing.

thanx for the response...yes i DO have hand guards, wouldn't ride in the trails with out them, i did a 150km single track enduro in sept and lost my left hand guard at check point 2...ran the rest of the race with out the left one and couldn't stand it.......still got first place though..woohoo....luckily i didn't loose it really, the nut came loose and fell out so i took it off and gave it to checkpoint 2 man and he gave it back to me at the end....

so i guess the 2001 426 flywheel and lighting coil won't fit mine? its going for 89bucks on ebay...... :)

ps. i forgot to mention i AM running a 13tooth sprocket on the front...49 on the rear(stock) bought a 52tooth havn't installed it yet...will see how that works.

Yes that wr 426 stator and flywheel will work. Grab it.

Here is the link to there site on how to Mod it for your YZ.


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