I tapped my cases on my K6.
Sharp metal hammer right on which made them to swell with ignition plate mounted. On the outside but not much from the side.
I had "do not crack in my mind".
Right on top must work too, let it swell both sides.
I hammered each one a little to hopefully get it centered.
A few turns around until plate sat tight.
Plate did not have any play sideways after that.
Plate sat with its 3 screws loose when I used the hammer.
My K6 case has alternative mark for correct TDC with advance max clockwise. It has a play before tighten it. That mark used when timing the cam.
Otherwise advancer in max counterclockward position before tighten it which match true TDC with stock mark.
I see now that this informative webpage is updated 2022!
https://www.motorcycleproject.com/text/sohcign.htmlCutting the advancer springs 1/2 wound another must if you want to get proper timing at idle with full advance not to early.
Done that on 2 CB750 (3 advancers). First for my Pamco ignition on my K6 that had its stock advancer with horrible sloppy springs, advanced a lot until springs had any effect.
I found Hondamans post old about it. One of the best free upgrades.
My K2 was not that bad but I could not get the ignition correct at idle. 1mm before the case mark (advanced). Fixing the springs made it. Full advance not too early either.
Both engines true TDC verified.
I have written about this in lots of posts now.
Hallelujah, I have seen the light!! (in correct position)
Only my K6 cases needed to taste the hammer.
My last build has really tight fit. Tested TEC and Dyna-S plate.
Late 1975 number.
My K2's 1972 cases also no need to hammer tighter.