750 Points ignition issue

[Simon Yates]

The status of the ignition points on my 1969 750 are as follows.

Oil pump gear - moved 3 teeth relative to the crank gear to retard the ignition. 
The range of adjustment (outer set) is now from 18 deg BTDC to 8 deg ATDC. 
Set the outer timing to TDC then establish the limits of inner set using eccentric adjustment it is 14 deg to 32 deg ATDC. 

Why is there this descrepancy between the inner and out plates which do not allow the inner points to be set to TDC?
I could vary the points gap or abandon the eccentric and extend the two slots slightly.

 

[piranha-bro2]

Sounds weird. Can only mean the points aren't sitting 180 deg apart on the backing plate. The eccentric screw isn't necessary for setting the timing. Any way you can achieve the correct timing with the correct gap is acceptable IMHO. I'd probably check the advance unit shaft for runout as well.

 

[Tippie]

I admire your patience, perserverence and persistence Simon. But if you just want to ride your bike and not worry about potential damage caused by wrong timing, you really aught to fit an electronc system. You have obviously a problem something like PB2 suggests. If the exercise is fault finding for the cause of the discrepancy, go for it. Alternatively borrow a full system with everything outboard of the oil pump drive gear and isolate the culprit. I?m sure someone here could help you out with that.
Contact breakers are, in my opinion, a simple pretty much foolproof system, which I have swapped for Ignitech on both my road and race SFs.

 

[martymoose]

Years ago I worked on yogi?s 750 points, the shaft had heaps of runout, earlier crash damage maybe. Remember it was a bitch to sort.

 

[MotoJouni]

Is it sure points are similar?

I mean if you get the timing correct for just one cylinder at one time.