The longest ever hybrid build.

Discussion for swapping a KDX motor in a MX frame...
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rbates9
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The longest ever hybrid build.

Post by rbates9 »

I just picked up a 2001 KX 125 dragger to do a hybrid project with and already have a few questions.

I have not seen anyone use the KDX swing arm. Why not? any reason?

Is the KX 250 shock from the same series the same shock?

More to come.
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Re: The longest ever hybrid build.

Post by CoronasAndChips »

Not sure exactly, I stuffed a 97' KX 250 rear shock in my 2002 KDX with KDX swingarm. 30 more mm of travel.
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Re: The longest ever hybrid build.

Post by bufftester »

The 250 shock from the same years is the same with just different spring rates (I used a 2001 KX125 frame with 2001 KX250 rear shock and forks). On the KX forks, 99-01 are the same on the 125, but 02 they changed (different dia and triples) as long as you match your triples to the same year as the fork legs its all good.

As for the KDX swingarm on the KX chassis http://kdxrider.net/forums/viewtopic.php?f=111&t=9125 this guy went that route, but never posted any follow up on ride quality. Biggest problem would be making a spacer for the swingarm pivot bolt where it passes through the frame, but a machinist buddy would come in handy.

Good luck on the build!
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The longest ever hybrid build.

Post by rbates9 »

I got my dragger torn down to the shock tonight and the length looks the same and the ends of the shock look the same. The body of the 250 shock looks a little bit different but the same shape so I think I will be good there.

If anyone can give me the KDX swing arm outside of the bushing to out side of the bushing measurement that would be great. From my eye balling measurements it looks like the KDX swing arm is roughly the same length as the KX125 and about 2" shorter then the KX250 swing arm. But the linkage for the KDX is also shorter then the KX linkage so I may be able to make up the difference in the linkage mount point on the swing arm with the shorter linkage. :hmm:

I would like to keep the KDX swing arm because I like the chain adjustment of the KDX much better then the KX. And I can also keep the KDX kick stand! :grin: Also I would rather add bushings to the KX frame to reduce the swing arm bolt hole to the KDX size then drill the case and be committed to the hybrid.

I plan on using many of the great ideas of the previous builds and add some of my own touches along the way. Maybe even be able to swap the engine back to the KDX frame if I don't like how the hybrid turns out.
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Re: The longest ever hybrid build.

Post by rbates9 »

bufftester wrote:The 250 shock from the same years is the same with just different spring rates (I used a 2001 KX125 frame with 2001 KX250 rear shock and forks). On the KX forks, 99-01 are the same on the 125, but 02 they changed (different dia and triples) as long as you match your triples to the same year as the fork legs its all good.

As for the KDX swingarm on the KX chassis http://kdxrider.net/forums/viewtopic.php?f=111&t=9125 this guy went that route, but never posted any follow up on ride quality. Biggest problem would be making a spacer for the swingarm pivot bolt where it passes through the frame, but a machinist buddy would come in handy.

Good luck on the build!

Thanks for the link!

I just took a look at the link you posted and it looks like it is a very easy fit so I think I will go that route for now. And as he said, I still have the KX parts to put back on if needed.

I measured the KDX and the KX125 swing arm from the center of the pivot bolt to about the center of the axle hole and they measured the same so the wheel base should stay the same. As for the geometry of the suspension, in my simple brain, I ride the woods and the KDX has woods oriented suspension so I would think that the KDX swing arm and linkage should work out good. And I think I might go with the 00 KX250 shock I have if for nothing more then the heavier spring.
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Re: The longest ever hybrid build.

Post by rbates9 »

CoronasAndChips wrote:Not sure exactly, I stuffed a 97' KX 250 rear shock in my 2002 KDX with KDX swingarm. 30 more mm of travel.
Could you notice any difference in the ride?
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Re: The longest ever hybrid build.

Post by bufftester »

From what I remember when I was measuring out my hybrid build, the upper shock mount is a bit higher than the KDX, but the lower linkage point is in nearly the same place in relation to the swingarm pivot. If you use the KDX swingarm, linkage and dogbones with the KX shock (which is a bit longer than the KDX) the rear geometry is pretty close to the all KX version. Then the only hurdles become bushings for the pivot bolt, and possibly shims for the swingarm itself (though I think the KX and KDX swingarms are the same width at the pivot...the KDX was spawned from the KX and engineers are really keen on preserving critical measurements for the sake of minimizing follow on testing.) That's what makes doing a hybrid so much fun-all the possibile combinations!
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The longest ever hybrid build.

Post by rbates9 »

I have been thinking about how to get the KDX swing arm mounted up and I think I can get a couple of bushings made up and welded into the KX frame then use the KDX pivot bolt.

I am trying to keep my KDX together as long as I can while building the KX frame up so I may need to pull the engine a few times and throw it back together for the weekends to go ride again.

Has anyone tried any of the aluminum radiators off ebay? They have sets for around $80 and the dragger I got is going to be in need of a set before I'm done.
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Re: The longest ever hybrid build.

Post by bufftester »

Check Ebay, any KX125/250 radiators up through 2005 will work (mine came off a 2004 KX250 and bolt right up to the 2001 KX125 frame) and I think I paid like $24 for both radiators and all the hoses.
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The longest ever hybrid build.

Post by rbates9 »

Good to know. Thanks. I started looking for some of the parts I know I will need and the new sets of radiators seemed to be about the cheapest way out.
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Re: The longest ever hybrid build.

Post by CoronasAndChips »

rbates9 wrote:
CoronasAndChips wrote:Not sure exactly, I stuffed a 97' KX 250 rear shock in my 2002 KDX with KDX swingarm. 30 more mm of travel.
Could you notice any difference in the ride?
I have to tippy toe now ( i only have a 32" inseam). The snow is almost gone so I haven't hit the trails yet but, the 97 came with a #190 spring in it. Although the front is way better just ditch banging the last week or so.
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The longest ever hybrid build.

Post by CoronasAndChips »

rbates9 wrote:I have been thinking about how to get the KDX swing arm mounted up and I think I can get a couple of bushings made up and welded into the KX frame then use the KDX pivot bolt.

I am trying to keep my KDX together as long as I can while building the KX frame up so I may need to pull the engine a few times and throw it back together for the weekends to go ride again.

Has anyone tried any of the aluminum radiators off ebay? They have sets for around $80 and the dragger I got is going to be in need of a set before I'm done.
I ordered a set yesterday for my 2002. will be here thursday or friday. I will post a review with pictures as soon as they get here. BTW the pic on ebay looks almost identical to the ones in the Myler add in DB magazine.
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The longest ever hybrid build.

Post by rbates9 »

CoronasAndChips wrote: I ordered a set yesterday for my 2002. will be here thursday or friday. I will post a review with pictures as soon as they get here. BTW the pic on ebay looks almost identical to the ones in the Myler add in DB magazine.
Do you have a link to the set you bought? It looked like there was 3 or 4 different brands, but they could all be the same. I would like to know how they work out for you.
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The longest ever hybrid build.

Post by SS109 »

I have been using ebay aftermarket radiators on my E. Seem to work well and have held up fine so far. Sorry, I don't remember which ebay store I got them through and it has been too long so my ebay history doesn't help. It might be in my original build thread or one of the other radiator threads here.
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Re: The longest ever hybrid build.

Post by CoronasAndChips »

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Post by SS109 »

Ah, I found who I bought mine through by checking my feedback! Here they are for your bike: http://www.ebay.com/itm/Kawasaki-KX125- ... 2c667ccdfd
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The longest ever hybrid build.

Post by rbates9 »

Thanks for that! If I remember right the set you bought were for a different bike then your E. If not how did they fit?
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Post by SS109 »

Yeah, I bought ones for an H-series since there were none available for the E. I had a lot of fun with the fitment since Kaw changed the mounting points just enough that I had to make my own brackets to bolt it all up. Definitely wasn't the easiest way to go but I like the extra capacity, the trick look, and they don't seem to be nearly as fragile as the factory radiators.
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Re: The longest ever hybrid build.

Post by factoryX »

If the kx250 shock is to long you could toss some lowering links in, just a thought.
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Post by rbates9 »

:hmm:

Been doing some thinking.....

From another thread there was some talk about not using the KDX swing arm for a hybrid build because the "reason for a hybrid is for better suspension and geometry". (Not exact quote but close enough.)

So, if my thought of reusing the KDX swing arm is going to be a draw back of the hybrid build then why not just do a fork swap and use a KX swing arm and linkage on the KDX frame? Seems like it would be much easier to just rework a KX swing arm then to screw around with the whole frame swap thing....

I am still going forward with the hybrid build my way but I am open to opinions. My goal is to do a hybrid to try out and if I don't like it be able to go back to a KDX frame.

From the looks of it I should be able to do what I am thinking about. Most all of the other (if not all) have a commitment point of drilling the cases out so I think that if I can make it work the way I want it to and still have a back up plan.

I have my brother working on some spacers for the swing arm hole in the frame to take the KDX swing arm bolt. When I have more to show then a bare frame I will start to take some pictures.

One other question. What over sized tank fits a hybrid better?
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