The 1927 Flyer should have a horizontal carburettor mounting for a clip-fitting carb, onto a cranked alloy stub, which mounts onto the usual three-stud flange on the engine. The carb on later Flyers, TT Reps, etc., fits at an angle of 38 degrees, and so the float chamber mounting ‘banjo’ has a twist of 38 degrees in it to make it level.