2000 vs 2001 flywheel/rotor

I'm going to install a WR stator on my YZ426. I've read that the WR426 to YZ 426 is a direct swap.

I also read that the 98 and 99 WR 400 have a lower output stator (wattage) than the 2000 model. The 2000 WR 400 has the same part number as the 2001 WR426 stator: 5NG-85560-01-00

My question is the flywheel - which one do I need to get and why do they have different part numbers?

2000 WR 400 flywheel: 5BF-85550-01-00 (also says 5GS5)

2001 WR 426 flywheel: 5NG-85550-01-00 (also says 5NG1)

Does one change the output? Stator cover is the same part number, so I don't think they have different dimensions, at least on the outside.

Are the crankshafts different? Different taper perhaps? If the two flywheels will work on the same stator part number, maybe that is the different.

since the piston and connecting rod is different on the 426 compared to the 400 it could be the weight of the flywheel making a different part number. if the left side crank wheel is the same then I would venture to say the taper is the same,as would the cut for the woodruff key. from what I see 2000,2001&2002 yz and wr all have a 5jg left crankwheel.

I am going to assume that you have a 2000 426 and your question is basicly do I stick with the year(2000yz426 to 2000wr400) or do I stick with the size(2000yz426to 2001wr426). Since you established the stator assembly to be the same so the CDI should be functional ,I think I would compare all of my homework based on size to try and find any more discrepencies

I've got a 2001 YZ426. I want to install a WR stator for powering lights.

Just looked and the left side of the crank is different on the 2000 WR400 than the 2001 WR426 and YZ426 which are the same part number.

Makes sense that the crankshaft counterweights are different for the 400 and the 426 and then the flywheel would have to be different.

Not sure if it is the taper only or if the flywheel mass is different.

Looks like I need to order a 2001 WR426 flywheel.

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