My good friend and confidante Malcolm Brown in NZ emailed me to say, forget about the Hughie Hancox carb-synch method. It is more accurate to cut up a welding rod and balance one piece in each carb throat to check if they are parallel (the time-honoured “lollypop stick” method). I tried it, instead using short lengths of snapped-off hacksaw blade, and found that I’d already got the slide aperture pretty much spot-on using the Hancox hand/eye method.
I further found that backing the throttle stops right off showed perfect parallelism (hence perfect synch) and winding the throttle fully open also showed perfect synch, but with the stops dialed in the synch could again be out. Then I’d hear a “ker-chunk!” and the carbs would be in-synch again. It appears that excess oil from my newly-oiled throttle cables had been running into the carb bore, evaporating and leaving a gum that was causing the slides to stick and not fully close. Removal of slides and careful cleaning fixed that problem.
