KDX motor in KX frame circa '86

arjay

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#1
Hi - just wondering if anyone's tried putting an aircooled KDX (C) engine into a 1986 KX125 frame. The frames appear to be similar, just that the KX comes with rear disc, bolt on subframe and rising rate linkage.

Thanks for any help.
 
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#2
Unless you get all the stuff for free I would just look for a newer style KDX?
 

arjay

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#3
I just like the idea of a well spec'ed 2stroke aircooled trailbike. Hopefully parts would be cheap.
 
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#4
I did this mod in 1987. I put a 86 engine into a 85 model KX 125 frame. The lower and upper engine mounts needed to be remade and the lowers welded. The KDX tank also needed mounts made aswell. other than that it went straight in. I ran 87 125 forks, rear disc set up, KX500 rear shock with high and low speed compression adustment. AWESOME BIKE I loved it and won many races on it.
Marty
 

arjay

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#5
Thanks for the info Marty. Sounds like a great low tech, low budget racer. I'm keeping an eye out for an 86 chassis with modern style linkage.
 
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#6
87 ?? This is really testing my memory but you have to get a frame pre split cradle. I think the 87 has a split cradle. I could not use your link to check.
Marty
 

arjay

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#7
Hi Marty - it's looks like 1986 was the crossover year - single downtube but with all the more modern stuff - rising rate, rear disc, subframe.