I found that the best way to time the engine was to forget about the timing light I bought and tune it by ear (or better by RPMs, dwell-tach as suggested by cjoe). I painted the ball on the flywheel, using a bit of krylon white paint applied with a Q-Tip (it does not really matter, just any paint that reflects light well) but I found that to run efficiently that I had to advance the timing beyond the opening that is available in the housing.
52pu has a good system there, but again I looked for max rpm at a given carb setting to establish a baseline. This setting was done at low rpms to ensure that I had not engaged the vacuum advance. Once I tuned to this point, I re-adjusted the carb for best mix and rpm.
While not the most scientific way, or possibly even the best method, it suffices.
Good Luck,
