another worthy mod i have found

another mod that improves the bike be it a WRF or a YZF is replacing the heavy non breathing std air box with a free flowing 2 stroke YZ air box.

My 98 WR 400 has had some tope end porting staintune full race exhaust countless carby tinkering and mods YZ timing and many other mods and the biggest improvement apart from the exhaust was the air box.

My mate has a WR 426 FN YZ times lid removed staintune exhaust carby set up mint and my 400 will eat it for brecky.


First I thought, "what the hell is this guy saying". Then I saw you were from down under and figured it out.

Good Day Mate!

KC :):D:D

[ February 16, 2002: Message edited by: MAD POTTER ]

sorry bout the typing was a bit tired when doing it, as now i am a bit under the weather. but anyone out there who wants more power do the air box mod i got it from the aussie yamaha race team so they know what they are doing

What year two smoker did you get the air box for and did it bolt right in? Did you use the stock carb boot with the new air box? :)


It wasn't your typing, it was the Aussie slang. Never heard of staintune before, or breky. I love it though :) Welcome to Thumpertalk!


Potter don't you know??? Staintune is an awesome exhaust from down under,..and "brecky" is what you eat before "lunchy" !! :):D


Got any pictures? I've wanted to put a 2-stroke box/side panel combo on mine, but would like to know what I'd need to do it right...


I need to get out from under my rock more often :):D:D


There's a good thread running on the YZ side for this mod right now. :)

sorry all i have been away a bit lately other people have been wanting their bikes fixed. I used a 2000 air box and side pannels coz i liked the white but any model from 96 through to 01 will work as yammy havent changed the boxes since then though the 02 is different but i think it would work.

I havent any pics but it was easy to slip into place it only uses the bolts on the rear gaurd to hold it in place, the top mount on the WRF box is not used on the YZ box so the new box has to be trimmed up to fit there, the WRF air manifold is used as the pilot and main air jet ducts are not in the yz manifold the wrf one fits like a glove.

i had to place some rubber on the RH side pannel as insulation from the muffler though i am about to attack it with a heat gun and bent it into the right shape. The RH side pannel i had to trim the supports off the gaurd so it can accomadate the overflow bottle.

i will work on gettinf some pics but dont hold your breath as i am far better aw spinning spanners and tuning bikes than i am at working a computer.

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