KX500 USING YZ250F YZ450F FORKS

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The question has been asked what it takes to install newer YZ250F or YZ450F forks on a KX500.
First things first, I grabbed a set of 05 YZ250F triple clamps and measured the distance between the fork tubes and they measure 190mm.
The KX500 fork tubes also measure 190mm so were good there.
Next I placed the 250F triple clamps into the head tube of a 94 KX500 frame.
Just about any year from 86 to o4 will have the same measurements.
Here is what I see.
The bottom bearing isn't big enough.

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The upper bearing is too big

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We seem to have plenty of top nut adjustment if we can find a smaller upper bearing.

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The steering stops should work just fine.

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KX500 TRIPLE CLAMP TOP BEARING MEASUREMENTS
ID 25MM
OD 47MM
WIDTH 15MM

KX500 TRIPLE CLAMP BOTTOM BEARING MEASUREMENTS
ID 30MM
OD 55MM
WIDTH 17MM

YZ250F AND YZ450F 2001-2013 TRIPLE CLAMP TOP BEARING MEASUREMENTS
ID 28MM
OD 52MM
WIDTH 16MM

YZ250F AND YZ450F 2001-2013 TRIPLE CLAMP BOTTOM BEARING MEASUREMENTS
ID 30MM
OD 52MM
WIDTH 16MM

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Here is a reply I received from a guy who has done the conversion:

You don't need to change bearings. Swap the steering stems. The original bottom seal doesn't fit exactly, but it does work good enough for me. The upper bearing will need a thin spacer to shim between KX stem and the upper YZ triple clamp. Then the upper clamp needs a slight material removal done so the stem nut on the upper clamp will have 100% thread engagement. Additionally the YZ forks are about 3/8" shorter than the KX forks. I have found the handlebar ergonomics are much better for me as I used to pull hard on the bars with the stock KX setup. I don't pull on the bars anymore. What also helped with rider comfort a lot was the wider footpegs.
The YZ forks has help me with handling as also the modified rear shock. The high/low speed adjustor modification stopped the pitching to the side of the rear tire in choppy sections and now when you adjust the shock, it actually helps. I no longer have to compromise for one type of terrain and suffer on the other.