- Wed Mar 25, 2020 2:32 pm
#88621
Having difficulty refitting auto-advance unit on my 1957 Bullet. You may have seen from previous posts I had the magneto repaired and am very much learning (or not) as I go along. My auto-advance unit has a single bolt running through it given its a 1957 bike (later versions I understand were modified) which is tightened up anti clockwise to pull the unit off the magnet (Lucas SR1) shaft through an external thread but tightens up clockwise onto the magneto shaft itself by way of an internal thread inside that bolt. This combination frees the auto-advance from the magneto. I am wondering in refitting do I remove the bolt from the auto-advance unit completely and then push the unit onto the magneto shaft. Once it is locked on by this means (as I am assuming in suggesting this there is some sort of inner ridge inside the auto advance unit to match the magneto shaft somehow)) do I then reinsert the bolt and tighten up clockwise? Sorry if this makes little sense to those more mechanically minded than myself but have tried leaving the auto-advance fully assembled with bolt installed but its very loose and even if it binds on the magneto shaft it spins the magneto rotor, won't tighten and disturbs the timing set up as advised in my workshop manual. This states set the points gap at 0.12 and then advance the cam clockwise to about 2 thou when the feeler gauge will just pull out. Auto-advance unit secured to fully advanced with engine 1/2 inch before TDC. All my timing marks on the relevant wheels are then lined up. The manual is unclear as to how to refit the auto-advance it just says try to avoid the unit slipping on the shaft. I know i could try this without asking but don't want to damage anything given the age of the parts. The magneto had failed so at least in taking it off have solved one problem to create for me another. Any help appreciated as usual. Trust you are all keeping well in the current situation. Hugh