KDX hybrid - opinions please?

[stable]

Hello,

After getting familiar with my old KDX, braking everything, fixing everything then getting pissed off with it cos it's so heavy to push when it does conk out I've been thinking about re-frameing it onto a KX frame.

It would also allow me to refurbish everthing with the re-frame. But my question is, is the KX frame that mush smaller and lighter. If I stick with the KDX engine, forks - basically everthing except frame, swing arm and tank (probabily exhaust) am I going to feel the difference?

I really don't want to throw money at this so want to use as much of the old KDX as possible. I got a mig, time and a big workshop though.

Many thanks for opinions. Oh and it's strictly a field bike project.

 

[julien_d]

what mean you by "late 80's" KDX? Is this a watercooled model? I have not seen a conversion done with an aircooled KDX engine, but would like to.

And yes, the kx125 frame is considerably more compact and lighter than your "late 80's" kdx200, and with MUCH better suspension.

 

[stable]

It is indeed an air cooled one - I do like air cooled - i know where I am :)

Cool, do you think the engine would fit ok? Can't be much bigger then the air cooled? And forks for that matter... anyone else see any probs?

 

[_JOE_]

Try to find a complete rolling chassis. Using the kdx forks probly isn't a great idea if you use the kx shock.

 

[stable]

well my rear shock is shot, hmmm.

 

[julien_d]

Ideally you want to find a roller, yes. You will not be able to use much of your KDX other than the engine, and hopefully the pipe. The swingarm and forks will just about have to be KX stuff. On the lighter side, you should be able to glean a good bit of funds back from the KDX bits if you sell them off on fleabay.

You'll definitely need to rework the pipe and make new engine mounts on the KX frame. You'll also need to figure out how to mount the swingarm, since the swingarm mount is most likely going to be different. As far as I know, you'll be pioneering this. I have not seen another aircooled KDX engine in a modern KX style frame. Unfortunately it will be very much trial and error, since you likely won't find anyone with hands on experience. kdxrider.net has a forum on kdx/kx hybrid's though, and you could probably get some good ideas studying up over there. It's been shown that damn near anything is possible given the ingenuity and determination to make it happen.

 

[stable]

well i'm certainly determind.. once I decide what i'm doing anyway!

Well if I can sell some of the KDX parts on i'm happy with that. Are they really worth anything?

I've found a cheap frame and swing arm so I'll start there I think - time to do some reading.

thanks all,

Tom

 

[bigbolx]

its not impossible but it's not going to be easy!!!
i looked into doing something similar a while ago using a spare old 'C' model 200 engine into a KDX 91SR chassis, the first trial of placing the engine into the frame threw up some problems

the front engine mount and also the rear engine mount/swingarm pivot area were out but could be modified to suit

but the major problem is the exhaust port exit is restricted by the frame

at this point i decided that it wasn't worth all the hassle!!!

hope this helps anyway and good luck!!!

 

[julien_d]

Nice info Bigbolx, that clears some things up. I wonder if a 95+ frame would make for a better fit?

 

[bigbolx]

went to a local Hare+Hounds on sunday and spotted an interesting modded C model

talking to the owner after the race it turns out he'd grafted on an early TM front forks/ brake/ wheel and had modded the rear end with a PDS shock/swingarm/brake/wheel off a KTM

here's a vid of the race....

http://www.youtube.com/watch?v=8KpHhsj1DfY

 

[james.keaton]

kdxrider.net has a forum on kdx/kx hybrid's though, and you could probably get some good ideas studying up over there.

If you are a member of that site could you possible help me get an admin to e-mail me at james.keaton@inbox.com? For some reason when I try to register it says that my email has been banned.

 

[SVandal]

Odd, maybe a gmail or hotmail account would work there.

For frames you may consider the 1st gen cr125 aluminum frames as the bottom cradle doesn't join, instead it goes up leaving a huge gap in the middle.

Here's one

While not as good as later cr frames, its still a step up over the old KDX one, especially with new suspension.