KDX250 TO KX250 frame

Discussion for swapping a KDX motor in a MX frame...
argclh6670
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KDX250 TO KX250 frame

Post by argclh6670 »

HEY PEOPLE...I HAVENT BEEN ON IN ALONG WHILE. just getting started on my hybrid build 92kdx to 96 kx250 roller...my question/concern is; cutting or opening up the swingarm cutout gap to accept the larger kdx case. it looks pretty straight forward...I was just wondering if any of you all have done this and if theres anything to look out for??? its a budget build, no new parts persay. hoping to end up with a much lighter better handling woods bike then the beast it is now!! ill post pics as I progress... thanks in advance for any and all suggestions or advice.
Last edited by argclh6670 on 02:35 pm Sep 14 2014, edited 2 times in total.
argclh6670
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Re: KDX250 TO KX250 frame

Post by argclh6670 »

so, I ve poked around in the hybrid cookbooks....but it seems that the swingarm modification images in cookbook 3 donot work. does anybody have ?
argclh6670
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Re: KDX250 TO KX250 frame

Post by argclh6670 »

is it common that when the swingarm is cut, it opens up into the hollow part of the swingarm??
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Tedh98
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Re: KDX250 TO KX250 frame

Post by Tedh98 »

Have you made the cut already? I wasnt sure if your question was asked after the fact.
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Postigo
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Re: KDX250 TO KX250 frame

Post by Postigo »

Hi, don't know if the kdx250 engine is wider than the kdx220 engine but I'm working on a 1998 kx hybrid with a 220 engine and there is some meat left after cutting the swing arm. If it's the same measure just be carefull during the cutting process. Look for 1998 kx in the hybrid section to see the pics. Hope this helps :supz:
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argclh6670
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Re: KDX250 TO KX250 frame

Post by argclh6670 »

Tedh98 wrote:Have you made the cut already? I wasnt sure if your question was asked after the fact.
No, i havent made the cut yet....just completed drilling case for swingarm n making sure motor mounts will work.
argclh6670
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Re: KDX250 TO KX250 frame

Post by argclh6670 »

Postigo wrote:Hi, don't know if the kdx250 engine is wider than the kdx220 engine but I'm working on a 1998 kx hybrid with a 220 engine and there is some meat left after cutting the swing arm. If it's the same measure just be carefull during the cutting process. Look for 1998 kx in the hybrid section to see the pics. Hope this helps :supz:
Approximately, how much did u need to remove from the sides?
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Re: KDX250 TO KX250 frame

Post by KarlP »

You really need to put get the motor and swingarm together on a bench to see what needs to happen. The sprocket needs to line up with the swingarm at the right spot.
Some combinations require cutting one or both sides of the swingarm, some require cutting one or both sides of the motor case, most need both.
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argclh6670
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Re: KDX250 TO KX250 frame

Post by argclh6670 »

KarlP wrote:You really need to put get the motor and swingarm together on a bench to see what needs to happen. The sprocket needs to line up with the swingarm at the right spot.
Some combinations require cutting one or both sides of the swingarm, some require cutting one or both sides of the motor case, most need both.
Its looking as if the cases need to be cut....its roughly 10mm coming off on both sides....my concern with cutting the cases is the pressed in bushings on the cases, which are approximately an inch long... Im worried that may be taking too much of the motor mount away? Hopefully im making sense.
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Re: KDX250 TO KX250 frame

Post by Tedh98 »

Do you have a picture of your swingarm? I am trying to understand your concern with cutting it.
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Re: KDX250 TO KX250 frame

Post by royadams »

On my kdx 250 to 2000 125 hybrid I had to cut the case as well as the swingarm. There was not enough of the swing arm there to cut with out getting in to the swing arm its self.
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Re: KDX250 TO KX250 frame

Post by ArkAngel »

Pics Pics Pics :p
KDX 200
KDX 250
argclh6670
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Re: KDX250 TO KX250 frame

Post by argclh6670 »

Tedh98 wrote:Do you have a picture of your swingarm? I am trying to understand your concern with cutting it.
ImageImageImage
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Re: KDX250 TO KX250 frame

Post by Tedh98 »

All makes sense now with those pictures.

If you are concerned with cutting too much away from the engine, what about cutting the brake side of the swingarm and the shifter side of the case?

This issue now seems vaguely familiar now. I am thinking that someone else had the same concern and wound up using a different year swingarm that could be cut on both sides and kept the cases intact (well except for making them 17mm ID).
argclh6670
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Re: KDX250 TO KX250 frame

Post by argclh6670 »

Tedh98 wrote:All makes sense now with those pictures.

If you are concerned with cutting too much away from the engine, what about cutting the brake side of the swingarm and the shifter side of the case?

This issue now seems vaguely familiar now. I am thinking that someone else had the same concern and wound up using a different year swingarm that could be cut on both sides and kept the cases intact (well except for making them 17mm ID).
that's the way im leaning now....just as you suggested.
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Re: KDX250 TO KX250 frame

Post by Tedh98 »

This link is why this is familiar now:

http://www.kdxrider.net/forums/viewtopi ... rm#p128285

Looks like a '99-02 swingarm will make your life easier.
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Re: KDX250 TO KX250 frame

Post by bufftester »

Yes, the 99-02 swingarm has a larger wheel area and more flange to cut. They are fairly cheap and plentiful on Ebay last time I looked.
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Re: KDX250 TO KX250 frame

Post by Postigo »

The Doctor says I have multiple personality desorder... But we are not agree...
argclh6670
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KDX250 TO KX250 frame

Post by argclh6670 »

well people ive got the swingarm n mounts all squared away. radiators n airbox all fits well. however, my swingarm im assuming is off a 97-98??? cause the brake caliper mounting bracket is different...I didn't eve think to look at the dang thing. below are pics bottom pic is off the caliper off the kdx250.....suggestions?? anybody have an extra mounting plate that'll fit they're willing to part with??Image
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Last edited by argclh6670 on 09:04 pm Sep 19 2014, edited 1 time in total.
argclh6670
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KDX250 TO KX250 frame

Post by argclh6670 »

im sorta confused on what the mounting plate should actually look like...below is a pic, is this it??
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