It's a shame you didn't post earlier or read some of the other posts. You would have found virtually every 250/300 rear hub set would interchange from 1994-2022 and that any KLX250S/300S front hub would interchange. The rear hubs were also used on a lot of KX models. I think the only thing that changed over the years was at one point they went to a larger carrier bolt set and that simply required a rotor be drilled to suit with a power drill. I remember having to do that to fit a used KLX300 220mm rear rotor I mounted on my '09 KLX250. The only stopper in universal fit for the KLXs was when they went to an electronic speedometer. Otherwise all of them would fit.

You should be able to locate a correct front rotor in either size. The KLX650C ran a 300mm rotor if you found one of them, but I think you can find the correct size aftermarket if you look for the right thing. They likely won't have one listed for your bike yet, but any rotor from the 1993 KLX650 through the 1994 KLX250 on through the current 300 have the same bolt pattern and are totally interchangeable. It is just getting the right 300mm for your bike.

Your other option is to get the front caliper carrier from an S model 2009 or newer which will make a 250mm rotor fit your bike. Those rotors are easy to find. All of the KLX and some KX and KDX model rotors fit. I know, my bike has a salvage rotor on the front that was marked as a KX. They are easily found on ebay, often for less than $50. I picked one up for $20 figuring it was worth it in case my brother or I bent a rotor.

The carrier that mounts the caliper to the fork leg is the key to the change. The way the mount is usually sold is as a combination of the caliper and mount when looking used. The forks changed in 2009, so it may be that the earlier mounts won't work, I don't know for sure, never looked. At one time I had a KLX650C 300mm rotor and was going to mount it on my 250. I found a used carrier, but realized I didn't really need the stronger brake, the OEM was two fingers and able to make the front tire start to squeal so I didn't do the change. I sold off the rotor and hub set I had for a couple hundred. I would bet if you changed to the smaller rotor you could sell the large rotor and the carrier to pay for the caliper and rotor and money left over.

 

I'm very much aware of the cross compatability that had been discussed on here. As stated there were none available in the used market with the electronic speedometer drive either as just a hub or a complete wheel. The rear wheels I found were all in rough shape.

I used oem dual sport wheels and oem sm rotors and a speedometer correction box so it is all plug and play aside from swapping the chain for the different gear ratios but I have a master link in both chains.

I spent several weeks looking for used wheels and or hubs and reached out to multiple wheel builders and all came up negative. Woodys stated their hub vendor was having issues with the hub causing a malfunction indicator light on the efi klxs. I don't see how that's possible but that's what their answer was. The rest straight up had nothing to offer unless I wanted to get custom spacers and switch to a magnetic speedometer like a Trailtech.

So I agree, you can go used and make it work or you can use genuine parts from the current model year if you can wait.

 

I picked up a 2022 KLX 300 SM as well and I've been looking for another set of tires but nobody is selling anything in my area unfortunately. Prob gonna just bite the bullet and go with the OEM ones. I'm thinking that I'll just get a 21" front wheel since there's a 4 inch difference between the 17" stock SM wheels. Difference is only 1" in the back so I don't think it's worth the hassle. Dealer quoted me $800 for the front wheel and I live in the SF Bay Area.