KX 125 / KDX 200 Conversion

[Svock]

Well....Here Goes!

I have been wanting to do this conversion for a while now. I say it is time to jump into it! The plan is to take my 1997 KDX 200 engine and place it in a 1999+ rolling chassis. I will be parting out the components from my bike, that I will not need on the Parts Wanted/For Sale Forum. Also, I may need assistance in obtaining certain parts for the new chassis. I plan to document this swap on this thread.

 

[Svock]

I am just about done with this project, and I guess I could let you guys know how it went. I ended up settling for a 1996 KX 125 frame and swingarm. This is the same set-up from 1994-1998. I used forks off of a 1997 KX 250. I got the forks for $130 on ebay, with a damaged lower left tube. I work(ed) at a Kawasaki dealership, so I got the replacement fork tube for $150. I thought I had scored an awesome deal, but when I dissassembled the forks, the inner fork cylinder was also damaged. The second cyclinder was another $100 with my discount. BTW: The fork tube was damaged by the previous owner's wife smashing them in because he was riding too much. :eek: The forks alone cost me $450 with my discount after various parts such as seals and oil. But, as a surprise they included Pro-Tapers with adapters from the stock 7/8th handlebars. $450, a bit pricey, but live and learn. I also had to replace the front wheel with a KX 125 wheel which ended up costing $180 with axle and spacers and all. :(

To make the swingarm fit the KDX engine, I had to grind aprox 3/4" off of the inside of each swingarm arm, as the KDX engine is wider than the KX 125/250 that the swingarm is originally designed for. Also, I had to bore out the KDX Engine cases to fit the new swingarm pivot bolt. This was a project in itself and took three High Quality drill bits ($22 each) to do it. As the KX swingarm is longer, a new, longer chain was required. I was able to use my KDX rear wheel with only minor modifications. I removed the dust cap from the left wheel spacer, and shortened the spacer by a few millimeters.

I decided to use an IMS 3.2 gallon tank for the 1994-1998 KX 125/250. BIg mistank. (no pun intended) The bottom of the tank had major issues with the larger/taller KDX engine. The IMS tank came down about 1 inch too far. This caused the tank to sit much too high in the frame. I ended up heating the tank with a heat gun and re-molding it to the proper shape. In the process I managed to create one large hole, and several smaller holes in my $230 IMS Tank. JB-Weld is my new best friend. All of the holes seem to be patched, and holding. We will see what happens after the first ride.

With some persuasion the lower motor mount (on the frame) lined up with the engine. The front/lower engine mount was miles off, and was sawed off and replaced with a giant overkill, custom mounting plate. The upper head-stay mount was custom fabricated from plate alumminum. The KX frame has no provision for a rear headstay mount, so the stay was machined off of the head. I must say, that if I were to do the conversion again, I would have also removed the lower engine mount, and fabricated a new one as well.

Needless to say, custom radiator hoses were required as well as a new provision for an overflow tank. I used a 2001 WR250F overflow tank that fits neatly behind the left rear numberplate. Brakes were the easiest part of the project. By simply switching over their carriers, they worked perfectly. The carburetor took much persuasion to get it to fit into the much larger KX airboot properly. The KX intake-to-carburetor space is much smaller than that of the KDX so, removal and reinstallation of the carburetor is VERY cumbersome. The carburetor is wedged perilously into the small confines of the KX frame.

With the new, larger handlebars, a new way of mounting the handguards was required. I used Summers Racing Components tripple clamp pinch bolt mounts to mount up the Freddette Racing Handguards. The rear brake mounting pivot is non-existent on the KX frame. I had to fabricate a spacer/bushing to bolt the rear brake lever onto.

There are many other little things that I had to do, and as they come to me, I will continue to post them on this thread. Also, pictures and a ride report will soon follow. Also, I am thinking about selling this bike, if anyone is interested. I can't to find a listing for it in the Kelley Blue Book. KX 200???

Svock

 

[CaptainObvious]

Man, what a nightmare. Is the KX frame that much lighter then the KDX frame? What is the advantage? It would have been much easier to just put the KX250 forks on the KDX frame, no?

 

[Svock]

Cheaper, Yes. As much fun? NO WAY. This project has been a blast, and I have learned MANY things. Easier? OF COURSE! The KX frame IS lighter than the KDX frame, and yes it makes a difference. It has been such a fun project!!

Svock

 

[CaptainObvious]

Well if fun was the motivator I understand 110% (checkout my signature).