making a 03 yz450f street legal

just got a 03 yz450f today and wanted to know what was needed to make it street legal

WR flywheel & stator

Lighting kit

Left mirror

DOT tires

Speedo

I'm sure it varies a bit by state, but I think that's pretty much it...

A horn is required where I live.

WR flywheel & stator

You cannot install the WR450 flywheel or stator on an '03-'05 YZ450 without changing the crankcases, crankshaft, and left crankcase cover.

Woah, good to know, thanks for the correction! I guess they're only interchangeable between the YZ/WR 400 & 426?

Woah, good to know, thanks for the correction! I guess they're only interchangeable between the YZ/WR 400 & 426?

Yup. An '06-'09 YZ can be converted without changing the crankcases, but you still have to change at least the left side of the crank.

Yup. An '06-'09 YZ can be converted without changing the crankcases, but you still have to change at least the left side of the crank.

Okay, so does this look right?

1998-2002 YZ/WR 400/426 - Stator/Flywheel are all interchangeable.

2003-2005 YZ 450 - Must change both crankcases, crankshaft, and left crankcase cover, in order to install WR stator/flywheel.

[2006-2009 YZ 450 - Must change the left crank half (or entire crank) in order to install the WR stator/flywheel.

Do you know if the 2010+ WR stator/flywheel work on the '06-'09?

I'm looking at picking up a 2010+ YZ450 in the couple/few months, I don't imagine any WR parts fit that motor?

Edited by corndog

The '06-'09 also requires the left crankcase cover from a '07-'11 WR. The starter motor hole will need to be plugged.

'10+ YZ450's produce 140 watts as it is, and they have a DC system, so they have no need for additional power.

Great info, thank you sir!

Find an e-Line stator for the 03-05 YZ450F and you don't need to change the crank or cases. e-Line doesn't make them any more so you have to watch eBay or post something here looking for one - that's how I found one.

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