wr450f 2003 different diameter crank taper for flywheel

Hi there everyone I ordered a new full bottom end kit including crank, and when it arrived it seems to have a lot bigger taper diameter then the original crank that is in the bike at the moment?? My question is... is there a difference between wr450f 2003 to 2004 crank?? As I have purchased a starter clutch to replace my old which had shit itself with a 2004 starter clutch like other forums have suggested, it fits on the crankshaft that i have purchaced perfectly fine but the flywheel only just sits on with about 1 thread at the top showing which had lead me to believe the old crank is not a wr450f crankshaft? As im not sure what crank the original one is im kinda stuck whether to buy a new flywheel and what type? ? Thank you

The 2003 has a smaller taper diameter. It's the only year 450 that had it. In 2004 Yamaha increased the diameter as part of the upgrade for the famous starter problems the 2003 had. From 2004 onward they are all the same. If you want to use that crank you will need the newer flywheel to match. Any year after 2003 should work but just to be sure I'd look for something in the 2004 - 2006 range. Also note that the flywheel puller is different also.

Edited by PBDBLUE

Thank you heaps! So I have an updated flywheel eg 2004 flywheel, I heard the conrod may be different is this true?? Thank you

You're totally OK with the 04 crank and flywheel. I've done it.

Thank you so much mate !! No problems at all?

I'm surprised I'm one of the few that brings the oil jet upgrade to attention on these bikes. If you would like this crank to last longer do the upgrade ( mod taken from the quad motor). It directly shoots oil into the bottom of the piston and gets more oil to the rod bearing. About 20$ in parts and 40 to 100$ in labor

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