yz400 to 426 conversion

I have a 1998 yz400f and wouldn't mind having a bigger bike, I have a good friend with a wrecked 01 yz426f with an unharmed motor. Does anybody have any input on how hard it would be to convert the engine to my bike? :thumbsup:

Pull your motor out and put his in. I think everything should bolt up and line up but check to be sure. Give it a try one Sunday afternoon when the weather is really crappy.

I don't think the motor will bolt right in.

What you can do, and will be glad you did, is to take the 426 jug and have a 444 kit put in your motor. Some Kibblewhite valves and springs, and a little port work, and you can have a bike that makes more HP and torque than a new 450.

The 426 jug will mount up to the 400.

Eric Gorr's Forward Motion, Co. are experts at this procedure.

You should get his suspension to while your at it, assuming it will work. In other words just swap frames. Just a thought. :thumbsup:

I have 2 YZ-426. A real one 2000, and my other one is a 400 1998 with a 426 motor. Have no fear, everything fit right there, no pain at all. You will have to make some litle jetting change maybe ( i sugest you to have is 426 carb they work better than the one on the 400) . All the rest air box ,pipe etc everathing will fit. On my 2000 ( 426) i had a bad luck last year ( my chain broke the motor base and i replace it with a 400 base they fit exactly the same.So have fun.

Thanks for all the help i think i'll take the advice and put the motor in. Maybe mod it a little in the process. :thumbsup:

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