KDX220 air box and KX250 frame

[ebeck]

How similar is the KDX220 air box compared to the KX250 going back to 98-2002. Anyone know if the KDX220 airbox bolt holes will line up with the KX250 frame?

Thanks

[KDXGarage]

The back section of a KX airbox comes off, so that may throw off the bolt holes.

[ebeck]

Hmm, ok then, any idea if the KDX boot holes for the air box line up with the KX air box boot holes? Maybe use the KX250 airbox and the KDX boot?

[KDXGarage]

Sorry, but I don't know. What bike(s) do you have for the project?

[ebeck]

None yet. I am lining up what years of what to use first. Looks like KX from 98-2002 or so and the KDX motor from any year. All kinds of issues like air box hose size and it gets worse if you use a KDX200 carb with a KDX220 motor in a KX frame. The carb inlet size creates problems not to mention boot to aur box problems. Aluminum facrication could work as well though. I suspect if I go back in time far enough I can find KX's that used smaller carbs and come up with one.

[KDXGarage]

Any reason you want to use a KX250 instead of a KX125?

Pretty much all KX's in the last 20 years have had a very similar sized carb (38mm - ish).

1992 - 1993 are simliar KX models, followed by 1994 - 1998, 1999 - 2002 and then the 2003 and newer. I am not sure how different 2003 and beyond are compared to each other.

Someone recently stated that the 2003 KX125 had the head stay on the back of the head.

[don46]

You can fabricate a aluminum piece from the carb to the air boot. The kx 125 99-02 swingarm is about 1- 1 1/2" shorter than the kx 250. The frames are quite different, if I could use the 125 I would, The kdx bottom end is very similar to the 125 bottom end. I wouldn't sweat the air boot connection, that should be relatively easy, as with all conversions the pipe is the biggest issue, and maybe a late model kdx pipe will fit with minor mods.

[ebeck]

Hmm interisting thanks. Seems more 250's get parted out is why I was using the 250 is all.

Engine brackets have to be fabbed anyhow so is the shorter swingarm the main reason to use the 125 making it more nimble? In 2000 the KX125 and 250 had the same part numbers for bushings and swingarm bolt but the swingarm part numbers are different. The chasis mounts for the swing arm are the same at least. How is the 250 frame different? Heavier perhaps or stronger? I am very interisted in what you said if you can elaborate some please on why the 125 is better for this. I am not arguing I just want to understand the issues. [old 60's robot]Need input[/old 60's robot]