classic motorcycle forum

I was carefull not to disturb crank or timing/cam sprockets ,I did wipe the mag shaft before replacing the sprocket maybe I disturbed the timing then ,
I have set the piston full advance (lever slack cable) at TDC then back 7/16 BTDC watching for the points to just start opening before replacing mag sprocket ,
I am getting a bang back through the carb ,I have the advance /retard at mid way point
if anyone could help me to re time motor I would be very gratefull

yes a piece of "debris" inpregnated into the gasket , now I have a non starting machine, before I took the cover off I marked mag /crank sprockets lining up to the marks I put on the timing case
I feel sure I put back both sprockets as they were when the bike ran earlier in the day before I removed the sprockets /casing 
 I have checked many times the points just starting to open at 7/16 /12mm BTDC then fully open at 12thou just before TDC if anybody could post re timing engine /magneto I would be very grateful  thank you

oil weep problem found I think  bottom screw hole on gasket slight left ?
 now cannot get it to start , when I removed the timing/magneto case I was very careful to keep the inlet/exhaust cams in situ,
 all went back together no problem maybe timing has slipped ,I have points just opening at 7/16 BTDC then full open at 12 thou , I have a strong spark, what have I missed
 all input gratefully recieved
PS I started bike this morning ran no problems

That screw also possibly needs a fibre washer under it/them ?

Also, as you have to remove the sprockets in order remove the timing case  to change the gasket I would try just removing the bottom screw, cleaning it and coating it with silicone jointing compound and replacing it and see if that slows the leak.