HELP...plz everyone give me as much info as possibal! PLZ!

I have a 98 400 and have been out of racing for a while and im ready to get back in there but i want to wait til the 06's come out to buy a new bike. What options do i have to make it keep up with B class 450 riders? what 450 or 426 engine parts can i use and what mods are out there? also i want to give the ol' four double zero a face lift. i know about the the 03 plastic swap but i have no clue how to do it or what i need. i wish i had time to go through here and read every thread but i don't. plz help thanks!!


I would think a well tuned 400 would be fine for all but an expert level rider. You may consider a suspension revalve, depending on the track I doubt the motor is really going to be what is holding you back.

The weight is a handicap, but there isn't much you can do about that.

You can put a 426 jug on it, but you need to swap the con rod for the piston to fit. At this point it would probably be cheaper and easier to find a used 426, or used 250 two stroke.

Bottom line, if I was trying to be competitive on a YZ400, I would spend money on suspension and tires. Failing that I'd buy a 2 stroke.

Just my two cents.

get it jetted too, u'd be surprised at how well a bike will respond with a 12.7:1 air fuel ratio, even just to the 12 or 13 mark and you'll notice it. a friend just bought a yz426 and got 10-15% more power just from sticking it on a dyno and having it jetted

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