Auto advance cam position

[Phil C]

Something I've noticed on mine, which I may have mentioned a long time ago: when setting the points, I rotated the cam by turning the back wheel (is that the best way?), which, as it's in gear, is a fairly jumpy revolution. Watching for the points to reach their maximum gap, whilst turning the wheel, it would be easier if I knew where on the cam the high spot was. But the cam, rather than having a distinct apex, appears to be circular with a flat on one side. Where on the circular bit the apex is is not easy to spot, so I have to focus on the points gap and guess when they are coming up to their max in what is a jumpy revolution. I guess I need to find the max points gap, and mark the cam.  All comments appreciated as always.

You might also notice on the photo that I have about five or six washers on both my locking screws. Seems a bit ramshackle, but I guess it's okay. Obviously either the screws are too long or the sleeve nuts too short.

Phil.

[hoogerbooger]

points plate sanded so it will rotate ...  auto advance cleaned and oiled ......bent spring tab gingerly straightened ..... and everyting put back in... BUT can't set the timing/do the fag paper/ light bulb test. ( bother)

I've answered a earlier question of mine... the auto advance can't be be replaced at any orientation in rotation....it needs to ensure the right part of the cam, coinciding with the points opening, is in the adjustment range of the points plate  swivel... So it'll have come out again.

As I marked the spindle and replaced it in the same orientation it was, I have also answered why I was getting confused before and checked several times that I was at 33.5 BTDC and not perhaps 33.5% after ......or something else.

Oh well we all have to learn ( and thank you to all those with the patience to advise)

Phil: yes no obvious high spot on the Cam, but as far as I can see with the cam rotating anticlockwise the points are close on the lower flat-ishside of the cam, so the points open at the clockwise end of that lower flat-ish part.  after that it's sparked so if it does get fractionally higher I can't see that it matters....But happy to be corrected by others ( to avoid be positioning the auto-advance wrong again !)

[mashermick]

after a rebuilt engine on my 65 SS80 i turned my attention to thr distributor, as with just about everything on this bike ,previous owner had .ucked about with it.  the screw to hold on the rotor was broken off and the shaft hammered in ! nice one (of many) drifted out roll pin and stripped down, the action plate had 2 oversize springs and bent one side. marked 10 degrees ,purchased a  s/h action plate and new springs fron dragonfly cleaned ,lubed ,new point ,condenser concentrated on getting 15 thou gap then turned with a ignition lamp that lights as the points open (ebay)  now how to time ? r r book does not help much it says 15 degrees advance ,mine is 10.so the head was off so found TDC with a dial guage , I think about 34 degree Btdc should do it ,backing the piston to25 degrees add 10 degrees of advance pop in dizzy turn till point just open ,lock it up.....if and .when i get it going   I will let you know,   
hopeing its like the morris minor trick of getting it started with a loose dizzy and adjusting to the best tick over !

[mashermick]

probably i have not taken everything into account so will re set timing . a very confusing problem !