Do I have a 426 or 400?

So I bought an 01 yz426f and I googled the vin one day and I saw links with both yz426 and yz400.. And I was wondering if there is anything I can find on the bike to make sure what model it is. Thanks


Cylinder should have the cc on it. Don't remember the real differences. I think the carbs are different.

if you can't figure it out and are desperate, they have different clutches. just take the clutch cover off and if the basket has solid "fingeres" then it's a 426, if it has "V"ed ones then it's a 400.

To begin, the 10th VIN character is the year model of the frame. W, X, & Y are '98-'00, and 1 and 2 are '01 & '02.  The '98-'99 were 400's, '00-'02 were 426's (unless you have a WR, which are the same except the 2000 WR was still a 400.


That's not definitive, because a 400 will drop directly into an '01 or earlier 426 frame.  So, on the front of the cylinder, at the bottom edge near the right side, the engine size is cast in.  It will either say 399cc or 426cc.  


But again, it's hard to tell because the 426 top will fit on a 400 with a little fiddling, so then what?  If it's a 400, the clutch pressure plate will have 5 springs, the 426 clutch has 6. 


Also, on a 400F, the hot start control is mounted to a tab on the frame by the air box, with a hose running to a barb on the intake port at the head, while the 426 carb has the hot start built in; it has a red knob like the choke pull knob on it.

The year code is 01 and I have a red hot start knob next to the choke built into the carb. So it's most likely the 426 correct?

I finally found the displacement casting and its the 426 whew! I was worried I was lied to all this time!

I know that a 400 will have to code 5be all over the bike like on the kick start,carb,engine,brakes

I know that a 400 will have to code 5be all over the bike like on the kick start,carb,engine,brakes


As will a YZ250F and  YZ426.  A lot of 5BE parts were carried over for a while.  

Oh damn haha

Actually, a YZ400 would be a good bike to have just from a collectors point of view. These are the bikes (YZ400 and YZ426) that started the 4 stroke revolution. I had an '01 YZ426 and it is still one of the favorite bike I've ever had.

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