check the idle switch clicks, the wee linkage on the top of the tb likes to gum up so it wont close properly. undo the 13mm nut on the top and remove upper linkage arm and the bushes + spring. clean it all up, grease and refit. make sure you dont trap the spring in the plastic bushes or it will bind, when correctly fitted the arm should be completely free to move and will easily spring closed to hit the idle switch. if that doesn't help, loosen the 2 screws holding idle switch on and move it till the linkage hits it