interchangable 400,426,450

what parts are interchangable with the 400,426and the 450 motors... new to the thumper world and i have a tricked out quad with the yz400f motor....

Just about any part save the piston will swap between the 400 and 426, these motors are basically the same. Some changes made to the 426 are taller ratios for 1st and 2nd gear, a larger wrist pin, and an extra clutch plate.

I doubt many parts, if any at all, will interchange between the 400/426 and the 450.

Hope this helps.

Correct me if I'm wrong, but didn't they also increase the actual diameter of the clutch in 00?

Correct me if I'm wrong, but didn't they also increase the actual diameter of the clutch in 00?

I didn't think so Cowboy, but I've never compared them directly.


But I have (fairly reliable) second hand info that a '00 clutch, in its entirety, will drop right into a '99. Maybe the plates and basket are larger.


ok thanks guys i just wanted to know so if i need anything i know i don't need to look for 400 parts only...

I do know that a 2000 model has a seperate part # for the basket. Doesnt match any other year. Not sure about the others.

The whole clutch assembly is larger on the 426s than the 400s. That was an update that did on the 00 models. The clutch was further refined with the 01 model to make them less grabby. A great update for a 00 bike. The 03 450s went away from this 01-02 design, but there was a TSB about using the 02 clutch parts to update the 03 450 (just like the 00 426) to make the clutch smoother.

98-01 use the same rear swingarm, shock, linkage and suspension out back. 02-04 use a different setup. The swingarm bolts according to Yamaha is 1mm larger at the pivot point on the 02-04 bikes from the 98-01 bikes. The shock is also 5mm longer on the 02-04 bikes. That is probably the least swappable parts.

The most common part to swap from the 450s is the exhaust cam in the 400/426 bikes.

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