Re: rich running
Posted: Tue Jun 08, 2021 9:13 am
May I just add here Alex that you are not the only one with revving faults. A Moto Morini 125H that I have starts and ticks over beautifully, then revs freely once warmed up. But, since fitting a "VESPA" Ducati Electronicer transducer, as the original wouldn't advance. On this engine advance is 36°BTDC @6,000rpm.It now, after a 3 to 4 mile run, develops a horrendous bout of misfiring and failure to respond to the throttle, before clearing it's throat, usually with some monumental backfires and then continues the run (30 to 40 miles) as if nothing is wrong!?
The carb is a VHB 24 S and has a new needle and needle jet and all as per factory spec. The ignition is similar to that of the Ducati, in that there is a separate coil on the alternator for the EI and the trigger is on the adjacent stator pole. All of the tests, so far, have given values the same as the workshop manual. Tests to ensure that the ignition high voltage isn't leaking to earth through the common ignition/6v lighting ignition switch prove negative. The plug insulator colour is white with a lovely tan coloured nose. The 'silencer' is the original Lafranconi, the exhaust pipe is the same and the spark plug is the correct type.
I thought that I might have some dirty fuel, the first time, but clean fuel in a cleaned system has made no difference. The magnetic trigger was also suspect at breaking down once hot, but the continuing to run and rev to 9,000rpm, once the "throat" has cleared, would tend to disprove that theory, I think. I have a Lambretta alternative available to fit.
The joys of Italian "craftsmanship"!
Good health, Bill
The carb is a VHB 24 S and has a new needle and needle jet and all as per factory spec. The ignition is similar to that of the Ducati, in that there is a separate coil on the alternator for the EI and the trigger is on the adjacent stator pole. All of the tests, so far, have given values the same as the workshop manual. Tests to ensure that the ignition high voltage isn't leaking to earth through the common ignition/6v lighting ignition switch prove negative. The plug insulator colour is white with a lovely tan coloured nose. The 'silencer' is the original Lafranconi, the exhaust pipe is the same and the spark plug is the correct type.
I thought that I might have some dirty fuel, the first time, but clean fuel in a cleaned system has made no difference. The magnetic trigger was also suspect at breaking down once hot, but the continuing to run and rev to 9,000rpm, once the "throat" has cleared, would tend to disprove that theory, I think. I have a Lambretta alternative available to fit.
The joys of Italian "craftsmanship"!
Good health, Bill