05-11-2017, 01:48 AM
The immediate problem is sorting out the many SUs. Jeff Taylor covered this in a comprehensive article. There is little or no markings and bodies; pistons, can be and often have been interchanged. The horizontal models include 1 or 1 1/8 and are more appropriate for normal use and more vintage looking than larger semi dd.
A very different manifold required not in keeping with earlier model Sevens. The 1 and 1 1/8 innards seem to be the same so the difference probably of little significance.
As time progressed the axis of mount holes changed, lugs appeared for an air filter, piston material and weight changed, bore increased, and finally the light dashpot damped piston adopted, The latter on later Series E and sv Minor so relatively common and possibly the ideal. The original MOW needle in many of these a start.
If trading needle info the general installation and carb deatils (ie piston type and weight) should resonably match.
The jet must be unworn. A lot of time can be spent sorting needles etc, esp if optimum economy sought. Anything else in ign etc not optimum can lead to extensive waste of time.
I dunno about others but the dashpot modesl seem to be a marked improvement, including general smoothness, cf original. Polish nicely.
A very different manifold required not in keeping with earlier model Sevens. The 1 and 1 1/8 innards seem to be the same so the difference probably of little significance.
As time progressed the axis of mount holes changed, lugs appeared for an air filter, piston material and weight changed, bore increased, and finally the light dashpot damped piston adopted, The latter on later Series E and sv Minor so relatively common and possibly the ideal. The original MOW needle in many of these a start.
If trading needle info the general installation and carb deatils (ie piston type and weight) should resonably match.
The jet must be unworn. A lot of time can be spent sorting needles etc, esp if optimum economy sought. Anything else in ign etc not optimum can lead to extensive waste of time.
I dunno about others but the dashpot modesl seem to be a marked improvement, including general smoothness, cf original. Polish nicely.