follow the pics Ian posted .
the points cam shown in Ian c. pics
its the lump under the center screw
you can grab the top centrer of the points cam with two fingers and twist clocwise , or use a screwdriver or fingernail in the slot .
But it won't stay advanced on it own when the shaft is static .
to force it to stay advanced for static full advaced timing .
cut out one side of a small washer to made it loof like a C .
this washer can now be slid under the lossened center screw to help hold to cam in the full advance position .
use a small screwdriver in the top slot to lever to advance clockwise
and Tighten down the C Washer to lock it to full advance .
with the piston at 3/8" BTdc
the whole loosened distributor body can be rotated until the points snap a spark ( or lose continuity )
( or fag paper slips ) ... this is static full advace timing .
bolt down the dizzy , remove the C washer-stop and allow distributor to retard to its slack static position
If you have make a full timing mark , the bike can now be strobe timed to this mark . ( 2000 to 2500 rpm , don't have the exact spec)
If strobe timing is off , the whole distributor body only needs to be loosened and move clockwise to advance
Counterclockwise retard and and then clapped back down
this last pic shows part 425746 ... the points cam ,,, it lives on the mainshaft and under the points plate .
the cam has an stop arm that will show degrees of Advance stamped into it .
with the aid of weight and spings , the points cam can advance faster than the shaft
( until it hits its stop )