Today I took off my points plate, to check the auto-advance. Everything reassembled, I have been setting the static timing, using a light bulb.
I set 1 and 4 OK, but there is very little anti-clockwise adjustment left. When I came to 2 and 3. On max adjustment, the light comes on before reaching 'F'. It is about 2 degrees advanced, I'd guess.
With the plate for 2 and 3 tightened up, I slightly advanced 1 and 4 and that left 2 and 3 slightly less advanced. Now they are both about 1 degree advanced (light coming on just head of the 'F' Mark), with no further adjustment for the 2 and 3 plate and very little left on 1 and 4.
Am I doing something wrong here? I did wonder if the points cam / nuts were not properly seated, from checking the auto-advance. I removed them and reassembled with no change.
i've had trouble on occasion getting the 2 pairs of cylinders timed, using a timing light and a dwell meter set up on a 400f 76 to do both at once. after setting #1and4 then trying 2&3 that was off and moving it's plate i'd get the F mark in view and traveling towards the case mark, but quite a ways away from it, still moving the plate, the F mark would disappear, and it'd run like crap, after few times of that, and i wasn't sure which way it was traveling when it disappeared, so i started then on #2&3 first, only i set it Off as much as i needed it to go or half the distance that it was lacking to go, trying it per manual. and doing that, then setting #1&4 put both of them right on. something to do with the play the plate has. i tried shimming it once before that a pain to do though. i either did it that way or i started back on 1,4 but left it out of time as much as or half i can't remember, the distance that the 2,3 points would be off when the f disappeared.
Something I have noticed on many of the off-brand points plates since about 2002 or so is: they are too small on their OD (the whole plate). When one of these is installed it sits downward in the fixture (and screw slots) and this causes, from the start, an almost impossible geometry to set the points correctly. What happens then is: you set the #1-4 side onto the "F" mark with the standard gap and then the #2-3 side is not even close to the mark - and, it can't be reached, even when the gap on the #1-4 side is altered in any way(!).
In those situations you can usually get the timing closer on the #1-4 side by lifting the whole plate upward in the retainer grooves, but often with these plates it also requires widening the screw slots for the whole plate and/or the sub-plate just to get the timing marks to align. It's painful, but in the end it will actually work. Just to try it, I installed such a set on my 750 (around 2008 or so) and ran them for almost 2 years. They were Daiichi's Japanese-made versions and ran OK, except the pads didn't meet center-to-center: when Daiichi China jumped in (making counterfeits) the condensors came as junk, right from the package. That was around 2012 or so.
The OEM timing plates were originally the same for the 750 and the CB500 Four, when it came out. Later the 350F (and 400F), came out with its unique part number ID of -333-. The 350F plate had a slight (rotational) offset to its mounting screws that made it fit poorly when used in the 750: I still remember trying to make that work, once. This was being attempted because the 350F points (briefly) had ventilated stationary pads (contacts) on the -333- type partnumbered plates because of the soaring 10,500k RPM redline of the bike, and someone wanted to try them on his hopped-up 750 (in an AMEN frame) - so it came to me at the time. I ended up modifying the slots to make it fit the 750, but it didn't seem to change the performance.
