KDXRIDER.NET

I'm weighing pros and cons of tearing apart my complete 2003 KDX 220 and building a hybrid in a 2001 KX125 frame I have. I'm trying to mentally gauge the difficulty of the fitment issues and if it's worth doing.

As I've researched various builds, it looks like there will be a gap between the motor and pipe header. As far as I can tell, all the builds have the KDX pipe. Will a KX125 or KX250 pipe fit better? Do any of you have experience with this?

A KX125 pipe will not be tuned for a KDX engine, so even if it fit likea glove, it would suck.

A KX250 pipe won't fit a KDX200 / KDX220R. It also would not be tuned.

Yeah. I know they won't be tuned for the KDX engine. But adding an inch or two the header detunes the pipe also.

Baised on internet pictures, the 125 pipe looks to be a similar size of expansion chamber. However the KDX pipe looks to have more of a curl in it before the large part of the expansion chamber. It more resembles the shape of the 250 pipe. I'd assume the 125 pipe is a closer tune than the 250. But I could be wrong.

I'd also assume that the 250 pipe has a larger diameter on the header than the 125 pipe. Not sure if either match the KDX header diameter.

If you are going to do a hybrid, just get the KDX pipe. It fits perfect and will match the engine.

Using a KX pipe is a lot of work for sub-par performance.

I'm fairly sure a KDX pipe has to be extended for the 99-02 frame. (Which is what I have). I think it fits for the 03+ frame.

The only reason I would consider a KX pipe is so I don't have to make/modify a pipe.

Can anyone validate or deny this from experience?

I have the stock 2001 KDX pipe on my hybrid built on a 2001 KX125 frame. No modification was needed, no extension, not even a torque ring. It comes close to the frame but doesn't touch. The key is to mock up the exhaust with the engine before making the engine mounts so that you get it all lined up correctly.

bufftester wrote: The key is to mock up the exhaust with the engine before making the engine mounts so that you get it all lined up correctly.

But you do have to step back and make sure that the engine isn't rotated too far forward or backward, otherwise you'll wind up with issues of the chain and swingarm.

When I have done my hybrids, I position the engine where it needs to be and then deal with the fitment of everything else. Never a problem with a KDX pipe.

The kdx pipe will work in the 03 frame without mods, beyond welding new mount tabs to the frame to fit kdx pipe. the tricks the silencer. pro circuit and fmf change up things a little as well

I had to add about a 1\2 to the header on my 2002 hybrid to get it to clear the frame rails. fmf gnarly with a 2001 kdx 200 motor.