We started this conversation in another thread, but I wanted to document the process without hijacking another person's thread too much.
Dirt Bike recently had a feature in its Two Stroke Tuesday e-mail series about Pro Circuit Racing installing 2017 plastic on a 2005 KX 125. Needless to say, it looks really nice. One added benefit is that the tank and seat allow for a much flatter transition.
Pro Circuit is going to be producing a kit to recreate this conversion in the fall, but I figured I would try to recreate the results without waiting for their kit. The first step was trying to figure out which bike's stuff they used. The 250F and 450F have different mounting tabs for their shrouds, so all we need to do is figure out from the pictures posted by Dirt Bike how the shrouds mount. If you look closely, there are two outward facing bolts on the tank, which makes the plastic and tank 250F.
The two models share a subframe, so that is not an issue. We just need to figure out how they mounted it. Judging the distances from the exhaust and plastic mounting hole to the subframe mount on the right side, it looks like they just bolted that side up.
The left side is a little bit more of a challenge. It requires a bracket to get to the mounting hole. It should be pretty easy to fabricate, seeing as how the other side and the top will hold the subframe in place while you measure for the bracket.
The PC airbox uses the stock 125 airboot, so I imagine they just made a plate out of aluminum and mounted the 125 internals inside the 250F box. I did something similar on my 500 conversion, and it's pretty simple. You can buy just the outer box and front cover of the airbox from Kawasaki, so I'll be doing that. I'll cover the airbox conversion later.
The shrouds mount in three places with bolts, and will require at least a bracket off the radiator brace. The only thing I am not sure about is how they attach to the actual radiator. It looks like they are held in place by a plastic post. Thankfully, there are aftermarket louvers that you can buy that are relatively inexpensive. I'm thinking I may need to do some fabrication to attach the post to the two stroke louvers.
Kawasaki wants a ton for their seat assembly, so an aftermarket seat is in order. Unfortunately, SDG doesn't make a seat yet. Acerbis does make one of their X-Seats for it in black or green. There is also the eBay route, but there is only one listed and the seller wants more than the X-Seat.
I will be using the 2015 front number plate and fender that are already on the bike. The 2017 fender is not that different, and the 2017 front number plate is a bit flimsy looking. No sense changing a good look just to get everything up to 2017 standards.
That is what I have figured out so far. I will be looking for the parts used on eBay to save money, but it may be a little while to find them. I'll keep you posted.