78 KZ 650 f Timing trouble on 2-3

SO I have been trouble shooting my KZ 650 for a little while now and I had run into an odd issue.

Symptoms:

Rough idle, sounds like one set of cylinders is running well and the other not

Seems to run decently in low to mid range but once into the 5-6k range it doesn't have a huge amount of power and sounds like it may be stuttering a bit. Worsens by 6-7k.


Problem:

I have cleaned my points, both have some minor pitting in the centre but are otherwise flat and clean.

Point gap is correct (on the wide side of 0.3-0.4mm) ( I do see arcing between the points when running, but I am assuming that is normal)

I bought a timing light, For 1&4 timing at idle and ~3500 RPM to just about right(Perfect at idle and just shy of the double lines at ~3500) BUT at idle n 2&3 the timing is very jittery, varying between F T almost alternating between the two, and at ~3500 is a blur vaguely in the range of the double lines. As well at the higher RPM the strobe doesn't always fire, which would explain the stuttering.

Any educated guesses on what would cause this?

Main three culprit I can think of would be points, condensers, or the 2&3 coil. I should be able to replace the condensers easily enough, might be my next step.

Help/advice would be appreciated!

You sound on the right track. Replace the points and condensers first, or switch to an electronic ignition.
You could still have another issue such as a bad coil, or a bad plug wire/ wire cap. Could be a wiring connection. You could swap the two coils out, and see if the problem moves with the coil.

Smart idea on swapping the coil to diagnose. I'll look into that come morning.

Take the point cover off and start the bike when it's dark,
then look at the area of the points.

They do spark a fair bit.

Did you ever find the problem for the timing jitter on 2 and 3 ?
My kz650 is doing the exact same thing.
The spark plug wires on my 2-3 coil don't reach the 1-4 spark plugs.
It would be nice to know before I go out and buy a new coil.
thanks

I pulled the capacitors out of mine and measured them this weekend.
One was a about .26uF and the other is now about .091uF...
Maybe it's not surprising is that the one that measures .091uF has points that are sparking a bit more then I'd like....
but the bike runs good and I don't really notice an annoying misfire.

I also measured the condensers. Both are almost exactly .26 micro farads. I don't see much sparking.
I've spent most of the day trying different things. I did try switching the condenser wires but no change.
Replaced the 2-3 points also with no change. I also went as far as to swap coils around hoping that the symptom
would follow the coil. It did not.
So using the timing light I still have quite a bit of jitter on 2-3 and 1-4 are rock steady !?!?!?!?
I can't figure it out. What am I overlooking ???

I found another thread on this forum discussing this exact same issue. The thinking there is that this is a mechanical problem.
www.kzrider.com/forum/4-electrical/30581...-you?start=20#634123
Probably weak springs on the advancer.
I just can't understand how it can affect only one set of points ???
Seems to me that if the advance is jittering on one set it would affect the other since they are mechanically connected.