Remove the top of the air cleaner housing, followed by the element itself. After this, undo the screws holding the air cleaner box in place, and you'll see the top of the carburettor. You are looking for a spring loaded screw that operates on the mechanical side of the throttle linkage, and turn it anticlockwise to slow things up. You may be able to spot this screw without taking the air cleaner off, but it could be awkward!
John, June 2009
