Kiwi,
In regards to the "pipe" in the top of your carb, No my bike does not have it.
If you click on the Sudco link below and go to Carb Accsessories pg. 90 on the bottom right of the page you can find the
item your speaking of.
I have worked on a few other bike that had them. Pretty good idea I think to "get the cable around" the angle of the carb top and pointed toward the throttle with the least possibility of kinking, if you only have a few inches to make the transition. ( just like some of the clutch cables at the case mount)
There seems to be enough room between the carb top and the fuel tank on my bike that the angle isn't that bad,
and if you dont need to 90 right out the top of your carb you could probably "Lessen" the degree of angle to reduce the resistance of the cable in the pipe. Small tubing bender or bench vice should work, just beware of the possibility of a kink
, and not a bend..
http://www.sudco.com/onlinecat33.html I haven't had any luck decifering the #'s and letters on the carb body, nothing at Keihin.com or sudco.com.
I did look up the 2000 kx250 and it does infact show the "pipe" on the top of the carb. Hmmm...
The 250 carb is a 38s (I'm thinking -short-). It should "sharpen up" the throttle reponse at the cost of some top end if you have the 38.
Does the top of your carb screw on (round) or does it bolt on (shaped like the throttle slide, and flat) ?
Only reason I ask is the 38s has a top that is not the more traditional round screw on type, it's flat with o-ring gasket.
Tuck\o/