Topic: 1977 CB750 project is almost done but I can't figure out this ignition issue.

[Pielz]

So I have this thing running but it's suuuuper difficult to start without starter fluid when it's cold. If not impossible. I have new points and set the gaps properly, I just tested the ignition coils (4.5 and 5.5 ohms) 14.5k across wires. New spark plugs, new boots, set valve clearances cleaned the connections from the stator and tested it, it's functioning properly, new battery.. Fresh gas, freshly rebuilt squeaky clean carbs, idles around 1150 which is a little high but is as good as I can get it. I was trying to set the timing and my inductive light seemed to be inconsistent. On plugs 2&3 it was dead on but 1&4 it seems to bounce around. I can't get the indexing marks to stay in one place. That's why I think it seems like it's inconsistent. I don't believe it's the gun. I got a decent one. I just can't seem to figure out why I can't get a good reading. Anyone have any input that they could give? I have a feeling it's an issue with my timing that's causing hard starts, high idle, and poor performance at 60mph+ but I'm having a hard time even getting the timing in with being unable to get an accurate strobe. Id appreciate any input.

[754]

They like to start with throttle closed.

[Pielz]

Do you mean just not giving it throttle when kicking it over or running the starter? I typically don't give it any when doing either of those. There's sort of a sweet spot where the choke does more than off or full on.

[Bodi]

The timing light strobe should be equally stable on both coils. The mark may dance around F at idle, that's just the advancer twitching around, usually settles down after a carb sync. Marks should be dead steady at advance (above 3000 RPM or so) once the advancer is on its stops at full advance, if they still move around there's something amiss in the advancer mechanism - probably worn and sloppy somehow.
I would check the points, if the pivot is worn it can shift around and change the timing randomly... not much, but enough to give a wobbly timing mark. Check the points faces too, if worn to a point or at an angle they should be dressed flat and square to the fixed bracket.
Badly worn out main bearings allowing the crankshaft to wallow around will also mess with ignition timing but I think other symptoms - clanking noise, vibration, oil leaks - would have grabbed your attention already.

[bryanj]

Bent stud from turning engine over with big nut at points end will do it as well

[Pielz]

Awesome. Thank you guys. First I think I'm going to look in to replacing my ignition coils. If it's a weak spark I've gotta do it anyway. As far as the advancer mechanism goes, think it needs lubrication and maybe some new springs? I haven't done a ton of research on spark advancers so I don't know much about them.

But Yeah it runs and sounds Rock solid so I don't think it's an issue of the cam having play. Also the points have less than 20 miles on them so its not an issue of poor contact surface there. The bike itself is in pretty decent shape inside, only 24 thousand miles on it anyway. I feel like that's not super low to seem neglected but not so high it's wearing out. Of course that varies from bike to bike and it may not look it everywhere but this thing was kept in a garage most of its life from what I've been told.