YZ426 450 cross

Just picked up a 2001 YZ426 with a "modified S" shaped rod, wasted cylinder and piston minus wrist pin matching "set". Given that the 450 is the same bore but 2+mm longer stroke, I'm wondering if I can mix the 450 cylinder and exhaust cam on the 426 head/cases. I'm guessing it would be a likely fit with a 450 rod but are the 426/450 head/case a decent match, ie; water jackets, oil returns, etc. Has anyone tried this before?

I've always been a 2-smoke fan and this is dirt 4-stroke #1.


Vince in Nor Cal

There is some evidence that the 450 cylinder will fit, but the 426 head will NOT fit on top of a 450 barrel. Both the head and jug must be changed if they can be used at all.

The 450 exhaust cam can be used in the 426 head, but now that there are aftermarket auto decompression cams for the 426, it's not as important a swap anymore.

what gray said. I have a 426 bottom end and have a 450 cylinder and head on it.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now