KDXRIDER.NET

I looked this up for my own reference, but hopefully someone else can get some good out of it. It came from a suspension vendor's website - rhymes with spacetech...so I can't claim everything is accurate. All fork sizes are inner tube size in millimeters.

KX500
97-04 end 46USD (upside down)
94-96 43USD
90-93 41USD
89 46 Conventional
88 and older 43 Conv., same as KDX

KX125 and 250 share same sizes for each year but different spring rates
02-07 end 48USD
96-01 46USD
91-95 43USD
90 41USD
89 46 Conventional
88 and older 43 Conventional, same as KDX

So the best choice to me would be to the 48mm or the 46mm. The 43's might be a viable solution, as well. Going any further back wouldn't make a whole lot of sense to me. No wonder the 97-04 KX500 triples are hard to come by...

Good info, thanks :)

It depends on what you are after. As you go larger, the forks have less flex, obviously. You might think that a good thing at first glance, but for trail riding it is good to have some flex. I have found 43's to work very well for my purposes, but I would also like to try a set of 46's on the KDX. 48's I think would be total overkill for trail riding. If you're going to see a lot of mx duty, that might be something to think about.

No MX for the KDX. Well, maybe just for practice. The powerband cuts off too soon. Good power for the woods, though.

Indeed. So, 43mm forks should not be discounted, especially if you can get some cartridge style vs the old damping rod setup.