KDXRIDER.NET

Hello all,

I've owned different KDX's, XR's, KLX"s over the years and have been a follower of this site for a few years now. I've always wanted to attempt a hybrid so this is the result so far, I still have some pipe welding to do, and am waiting for the rear shock to get back from rebuild/revalve. I had an old 90 kdx to start with that the guys at Moose racing originally built for my ex, and a friend had a very beat up 90 kx125 junker so in my spare time over the past 2 years i've been tinkering with this, my "low budget" kx200. Thought you might enjoy some pics. I figured it'd have been a shame to let such a nice engine go to waste, and heck the kx125 was 'almost free'! Can't wait for the first test ride.

Lookin good.

Front end looks high. If you measured the forks you would find the KX forks to be a few inches longer to the axle. The pictures show the front raked out. Try raising the forks i the lamps 2 inches if the bike pushes and generally hadles poorly.

It looks really good though. Very nice job. LOVE the gols Excels on there. PJ1 paint?

Front end looks high. If you measured the forks you would find the KX forks to be a few inches longer to the axle. The pictures show the front raked out. Try raising the forks i the lamps 2 inches if the bike pushes and generally hadles poorly.

I think the rear is actually low, it's supported with straps until my shock gets back The front is also hanging from black straps, barely touching the ground, no real weight on it, just enough to keep it from swinging from the rafters! I'll make some adjustments as needed IF i ever get my shock back.

I had everything powder coated kawasaki green with added gold metalic, reinforced some cracked areas of the frame, bike was supercrossed in its first life. Most new parts were bargains from ebay. New old stock forks $99, New front wheel $79, Seat cover $5, end result, hopefully priceless. Just saving about 25lb over the 1990 non perimeter model should be worth some grins. I know its tons lighter then my friends 220.

Hey not bad at all , good work !!

Looks good, how was the kdx motor for slotting into the frame? Any adjustments to the rear mounts?

Thanks. When you use the 90-91 kx frame the 90 kdx engine bolts right into the frame/swingarm pivot, no mods at all to the rear of the engine or the swingarm, so there are no alignment problems, uses stock kx pivot bolt. You have to cut off the forward motor mounts from the frame and reweld new ones on, once the swingarm bolt is in place you can rotate botton end up and down to help locate the new mounts while you tack them in place, piece of cake. Cut the head stay off the rear of the head, replace the front 2 cylinder head studs with longer ones then fabricate a new stay to connect to forward upper frame mount. A little work with a heat gun to the bottom of the gas tank to clear the rear of the cylinder, have a kx radiator mount welded to the kdx right radiator, and welding the rear half of a kx pipe to the front of a kdx fmf pipe and the project's 98% done.

This has to be the easiest hybrid possible for the older motors. Not the most modern kx frame for sure, but with the Slavens modded suspension it should be light years ahead and lighter than any stock framed 200 or 220. Biggest plus may be how cheap the 90-91 kx125's are now

If anyone's interested and can find a July 1991 issue of Dirt Rider there's a pretty complete article on doing the swap. Or PM me and i'll make copies for you, I'd post the article but my computer skills are very limited. Maybe i could mail someone a copy who's knows how to post it????

NICE! However, is the 90 KX even an an improvement? All that excel running gear would've sourced a newer frame. My 89 KX250 handled worse than a 95+ KDX w/ USD forks, much less a 95+ KX conv.

The 89 and prior kx's were the wider non perimeter frames, very similar to the 90 kdx frames. I have a 96 kdx with kx forks and while its an improvement its still fat. Just shedding lbs and adding decent suspension should make a world of improvement. I rode the kx125 once before tearing it apart, and even with thrashed suspension was much better in the woods than the stock kdx, except for the weed eater 125 engine of course. Much more flickable and light. I have a friend scanning the original article for me to post. They pretty much said it was more than a match against anything out there at the time and couldn't understand why Kawasaki never made a kx framed kdx. The 90 frame was larger than the current kx's but at 6 ft 200 lbs it should be about right. I have a 220 engine under my workbench waiting for my next winter project, i'll start scanning for a doner chasis in the fall, if this one isn't up to snuff i'll at least swap the front suspension and wheel to the next bike. If I try something with an alum frame might be a good excuse to buy a TIG welder????? I'm sure somebodys blown up their kxf250's by now

Has anyone attempted a hybrid with one of the Kawi aluminum 4 stroke frames??? Or maybe even the other way, into a kx100 frame for someone shorter?

marrk_us wrote:The 89 and prior kx's were the wider non perimeter frames, very similar to the 90 kdx frames. I have a 96 kdx with kx forks and while its an improvement its still fat. Just shedding lbs and adding decent suspension should make a world of improvement. I rode the kx125 once before tearing it apart, and even with thrashed suspension was much better in the woods than the stock kdx, except for the weed eater 125 engine of course. Much more flickable and light. I have a friend scanning the original article for me to post. They pretty much said it was more than a match against anything out there at the time and couldn't understand why Kawasaki never made a kx framed kdx. The 90 frame was larger than the current kx's but at 6 ft 200 lbs it should be about right. I have a 220 engine under my workbench waiting for my next winter project, i'll start scanning for a doner chasis in the fall, if this one isn't up to snuff i'll at least swap the front suspension and wheel to the next bike. If I try something with an alum frame might be a good excuse to buy a TIG welder????? I'm sure somebodys blown up their kxf250's by now

Marrk us, I live in Woodland Park, CO and I would love to get some more information on your hybrid conversion. I tried to pm you but was not able to. victor@warpdriveonline.com

Update--- Just realized I never gave a real ride report of the finished bike. I bought a nice 93 kdx200 to ride to get used to the engine again while finishing the hybrid. I'd also been riding my 96 with 220 head, piston, and kx forks.


So on one of the first rides some friends went along and we took all three bike to be able to switch off and compare. We ride just west of Colorado Springs, the trails range from jeep trails to lots of tight woods and rocky climbs, with a lot of switchbacks. After a long weekend, lots of fun and a bit of bench racing over beers heres what we came up with.

93-kdx200- fmf pipe, torque reeds, stiffer fork spring, other wise stock- Still a very good woods bike. A little wide, wonderful engine, it can get a litttle out of hand in the whooped out sections of trail and the forks tend to deflect off objects rather than tracking straight through like the other 2 bikes. With a set of kx forks the 89-94 kdx would probably make most people happy.

96-kdx200-upgraded to kdx220 top end w/wiseco piston, fmf gnarly pipe, Jeff Slavens tuned rear shock and kx125 front fork, torque reeds and heavyweight flywheel. This is the bike if you ride smooth and have ever been tempted to buy a four stroke. It has plenty of torque, can lift the front instantly over obstacles, and you'll save on front tires because its so much fun keeping it on the rear wheel. Not the engine if you're the point and shoot type of rider, because where the 200 will happily rev to the moon, the 220 is more 'John Deere' like, just pretend it's a four stroke and you'll love it. The handling on this one is much more modern feeling than the 89-94 framed bikes. It handles whooped sections much more calmly then the earlier bikes. With the stiffer frame and the kx forks it tracks much straighter through whooped out and rocky sections instead of bouncing off objects. Much less tiring on long technical rides.

kdx hybrid- 90 kdx engine, fmf pipe, kx250 carbon fiber silencer (w spark arrester of course) heavyweight flywheel, fmf torque reeds, torque spacers, oversized 3.6 gallon tank. Jeff Slavens tuned kx shock and forks. Based on 90 kx125 frame with newer kx250 suspension. This was by far the best of the lot. Since I first got the kdx220 it had been my favorite, but even with the kx forks it can't touch the hybrid. The 'newer' kdx perimeter frame is wider and slower steering the the 'old' 90 kx125 frame. A big improvement but still heavy. The hybrid ended up weighing almost 30 lbs lighter than the kdx220 and you feel every ounce when you ride them back to back. The hybrid tracks straight through terrain that the other bikes struggle to maintain pace in. And I just love the earlier kdx200 engine. In the lighter frame it seems to have enough down low and it still revs. It was time and money well spent. Now my 220 has been relegated to a buddy bike.

My only problem now is whats next? I already have an 04 kx125 frame just waiting for a transplant, and 2 engines, one late model, one early??? If anyone know how does the later model 200 run compared to the earlier version? Probably can't go wrong with either.

Victor, i've been riding every Sat on the Divide trails if you want to get in touch either pm me or email me marrk_us@yahoo.com. i'll answer any questions or maybe we can arrange to meet before I hit the woods, I live in Fountain and ride from my ex's place in Woodland.

Stay with the earlier "E" engine if possible. It is a better motor....

Any more build pics or detailed info would be awesome I have a 90 kx125 I've finished building but need more power. And I really like the idea of doing a hybrid. all I do is trails so this would be perfect. Is there any way of doing this without modifying the frame, just got mine powdercoated. If you could email me any info
warren.klosterman@yahoo.com

here is my bike.
http://www.thumpertalk.com/forum/showth ... p?t=827933

Here's the article that dirt rider ran on one of the first hybrids back in 91. This is my first time playing with a scanner so hopefully it comes out.












The only thing I did differently was I used the 90 kdx radiators to avoid the extra machining, as I never had any problems with overheating. This also allows you to use the stock kdx hoses. I had to shorten a couple of hoses as when mounted on the kx frame the radiators are roughly an inch closer. I installed longer studs on the front 2 cylinder head holes so as to have room for another nut to mount the homemade front head mount to the stock kx location on the frame. I don't have any pics of the mounts as I keep the bike in the mountains until winter hits. The pipe was the easiest part, simply cut off the long straight portion, mount the kx muffler, cut some regular car exhaust pieces to connect the 2 and your done. As long as you cut past the bulge in the pipe there is no performance loss. A nice side benefit from the thicker walled exhaust pipe used to connect the pipe and muffler is a much quieter bike. It's lost the loud ring, ding, ding of the typical thin walled 2 stroke pipe. Now all you hear is the muffler noise. Nice for sneaking up on 4 strokes and shocking them

Any other questions feel free to ask.

awesome Thanks so much.

Very nice job looks great ! I am going to do the same swap would it be Possable to give me a little more info on the pipe mods ? Mine looks totally different I have 3 to work with the e series fmf gold ,a h series fmf burly, and fmf gold from the 125 motor the 125 pipe fits but I doubt it will work properly any input would be helpful thanks

Original post date was July 2008, so this is from 7.5 years ago.

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