WR400 vs 426 vs 450

Alright guys here's my most important question. How does the 400 compare to the 426/450. How noticeable is the power increase? What kind of free mods can you do to the WR400 motor to get more power? What aftermarket mods? What seems to be the preferred exhaust for the WR's? Thanks

I have been lucky enough to ride all three in the last month. The 426 and 450 both pull a good bit harder than the 400. I know with the 426, all I had to do to get great power was YZ throttle stop, pull airbox lid, FMF pipe. Bike hauls the bacon. I have never touched a jet, and can keep up with a tweaked 450 on the straights.

Hey old bones, how did you get the extra 3/4" rise on the handle bars? I need some more than my J. Button highs offer.


If you buy fat bars (I got pro-tapers), you have two choices. New top triple clamp, or use the "universal adapter" offered by several companies. $35.00 from tusk. These bolt into the stock bar clamp, and bars bolt into the adapter. this adds 3/4" of rise to your bars. If you want to use this adapter, but don't want the additional rise, you order any of the bars that say "universal" in the name of the bend, they take the 3/4" back out of the rise in the bar.

See pic:


Will a stock wr250 muffler fit a head pipe from a similar year wr426? Thanks. Jack

I've recently (past 18 months) gone from a 426 to an 08 450. Biggest difference for me was the more linear power curve. When I first got the 450 it almost felt less powerful than the 426, as the 426 would come on with a rush in the upper rev range - like a two-stroke, where as the 450 just keeps building. But towards the end of a day of riding, on the 426, when my mates would accelerate or speed up on a certain section it was almost like "jeez, hold on, i've got to give it stick again, gotta brace myself.." due to the hit in the upper rev range. This was mainly due to my lack of fitness probably!

Love the 450 now though, and I'm probably quicker on it and can ride for longer.

Both are awesome bikes though.

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