Kdx250 trans in a kx250 for enduro

Irishman
Profile picture for user Irishman
Posts
107
Joined
6/7/2019
Location
IE
Irishman

Hi building a kx250 af for enduro have been looking at swaping out the trans for a kdx trans does anyone know if its really worth doing or even have info in a better setup thanks

|
nytsmaC
Profile picture for user nytsmaC
Posts
5956
Joined
8/10/2009
Location
Frig Off CA
nytsmaC 2/1/2023 11:37am
2/1/2023 11:37am Edited Date/Time 2/1/2023 11:50am

Have you confirmed that they are interchangeable? I’m fairly certain those KDX engines were from the 89-90 KX’s.. What year KX250 engine are you using? Assuming it’s newer, it’s not likely to fit. The 92-04 Kx250 engine cases were different from the 91’s.

You could try having a new 1st and 5th gear made by a machinist, which won’t be cheap, or see if they can source replacements in your desired size which is entirely possible.

coopernicus
Profile picture for user coopernicus
Posts
182
Joined
12/15/2019
Location
Broomfield, CO US
coopernicus 2/5/2023 12:00pm
2/5/2023 12:00pm
Irishman wrote:
Hi building a kx250 af for enduro have been looking at swaping out the trans for a kdx trans does anyone know if its really worth...

Hi building a kx250 af for enduro have been looking at swaping out the trans for a kdx trans does anyone know if its really worth doing or even have info in a better setup thanks

I've been considering this:

https://www.thumpertalk.com/forums/topic/902713-91-94-kdx-trans-into-a-…

 

Good luck!

Enduro_Malcolm 2/10/2023 7:49am
2/10/2023 7:49am

I’ve had a kx250 in the stable for a long time. Raced enduro, hard enduro, desert, 24 hour, endurocross etc on it. Fun bike and pretty dang capable. Like any bike, it comes down to the rider. 
I ran a 13oz fww, slightly retarded ignition, fmf gnarly, 18” wheel for the main changes. Other things were personal preference.

Oh and an IMS tank. It’s worth searching for the ims instead of the Clarke one, better fit and feel for the KX.

2007 KX250 FYI

Fangface
Profile picture for user Fangface
Posts
49
Joined
12/9/2020
Location
gent BE
Fangface 3/16/2023 1:32am
3/16/2023 1:32am
Enduro_Malcolm wrote:
I’ve had a kx250 in the stable for a long time. Raced enduro, hard enduro, desert, 24 hour, endurocross etc on it. Fun bike and pretty...

I’ve had a kx250 in the stable for a long time. Raced enduro, hard enduro, desert, 24 hour, endurocross etc on it. Fun bike and pretty dang capable. Like any bike, it comes down to the rider. 
I ran a 13oz fww, slightly retarded ignition, fmf gnarly, 18” wheel for the main changes. Other things were personal preference.

Oh and an IMS tank. It’s worth searching for the ims instead of the Clarke one, better fit and feel for the KX.

2007 KX250 FYI

Acerbis makes 11liter tank too :-)

Post a reply to: Kdx250 trans in a kx250 for enduro