yz400f head on a yz426 engine?

I am planning to buy a blown up 2001 yz426f engine (needs a new cylinder head assy).

So my question is, will a 1999 yz400f or 2000 wr400f cylinder head fit the yz426f? I would appreciate it if someone who will be going to the dealer can enquire for me cos the yamaha dealer here in Singapore knows NUTS!

alternatively, have anyone ever did the above?


Yes it will fit.I put a 426 cylinder and crankshaft in my 99 400, no problem.

Same chamber volume.

Bolt on swap.

Depending on the failure of the old head it could be repaired.

Many shops and wrenches are unaware of good cylinder head specialists that can weld up and rebuild most heads due to common failure issues, ie dropping a valve, seats falling out, cam bore seizure, bucket bore seizure, freeze cracks and the like.

All repaired for less than the $$ of new.

thanks for the both reply, what I understand is that the 1998-1999 (400) have a bore of 92mm whereas the 2000-2002 (426) have a bore of 95mm.... wont this cause any mismatch at the head and cylinder joint? :cry:

No, both motors have the same chamber.


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