Are all Carbs the same?

[SunDevil]

I was looking on ebay and I saw a Kiehn 39mm Carb but it said it was for a 250r. Would this work on a 400ex or would any other carb work, say from a raptor? Thanks

[Chef]

No, that 39mm keihin will not work for the 400. It lacks an accelerator pump. The pump basically squirts the fuel in the motor, and a 4 stroke needs that.