Motorcycle Repair: 1982 honda cm250c, cmsnl, partslist

Question
Hello, first off I wanted to thank you for doing this for free you guys have really been a big help.
      When you rev up the engine it stays at a high rpm and very slowly comes back down to idle. I disconnected the throttle cable and twisted the throttle by hand and it still does it so it has to be something in the carburetor, any ideas?

Answer
Erik, if the carburetor hasn't been cleaned for a long time, the slide could be dragging internally, but it is probably the the vacuum piston hanging up inside the chamber

http://www.cmsnl.com/honda-cm250c-custom-1982-usa_model1045/partslist/E++15.html

or intake manifold leaks at o-rings or at the rubber manifold itself.

http://www.cmsnl.com/honda-cm250c-custom-1982-usa_model1045/partslist/E++02.html

Bill Silver