Strobed timing mark wobble question at low RPM?

79 KZ650 with points. Now that I've got her running I'm working on some fine tuning. While setting the timing with a strobe at low RPM off the #4 wire (I assume this would be the exact same as the #1?) I get a noticeable wobble back and forth under the strobe. It's big enough to "walk" back and forth between a distance equal to the F and T marks. Should I be looking at my advancer even at low RPM or...???? I admit to being a points noob here as every bike I have has had electronic ignition either stock or installed (as this one will soon) so even obvious stuff is appreciated..

Thanks.

what do you have the idle set at. also have you set the points with a dwellmeter or just staticlly with feeler gauges

Idle is about 1000 rpm and it's set with a feeler gauge.

Check to see if is does it on the 2/3 set of points. If the strobe doesn't wobble on the 2/3 set I don't think it could be related to the advancer otherwise it would affect both points sets. Ed

The advancers wear so that there is no spring tension at fully closed (idle) position which lets the weights wobble. Just had this problem on my 750 twin. I fixed it with new springs, but I had to make them. If it is the advancer, you can probably wiggle the weights some. They need a little bit of spring tension when fully closed to keep them from wobbling.

Good deal. I'll double check all of that. Thanks Gents.

This thread may be of interest.

Click here > tighten advancer spring

Good Luck!

Excellent! Thanks Patton. Good to know that the springs can be salvaged if need be.

I've had time to really go through the ignition without rushing. Advancer looks to be in excellent condition. It's lubed up and moves smoothly. I know you can't really tell just by by looking at them but the springs don't show anyting out of the ordinary.

So after double checking all the connections and point gaps I put the light on it again and I get a noticeable wobble on timing mark on the 1-4 and none at all on the 2-3. The mark is dead solid under the light. Points and condenser are brand new.

Should I be looking at my coils?

Rather than buying coils, you can try swapping them to see if that's the problem (if it is, the wobble will move to the 2/3 points), but I'm betting you see no difference. I have the same wobble on 1/4 and none on 2/3 (2/3 is so steady it looks like a still photo). I have replaced timing advancer unit, condensers, points, coils & wires, spark plug caps, and spark plugs with NOS parts and tried WG coil mod. I also tried swapping everything swappable between the 1/4 side and 2/3 side including the wiring. None of this work changed that wobble at all. The bike runs great, and the wobble dissapears above idle. This winter I plan to take a very close look at the valve adjustments to ensure they are all exactly (or as close as possible) the same. The wobble doesn't actually annoy me because it doesn't appear to affect the running of the engine and it's been there for at least 25 years. However, the detective in me keeps scratching his head wondering what could be the cause. If I ever figure it out I will post the magic answer; if you figure it out first, please tell us the secret. Ed

Hmmm... Interesting stuff and I appreciate your response. I also have a bit of a detective in me also and I would have gone down all the same paths that you tried. And I probably still will of course because I just can't help myself ...

I'm going to install a Dyna S in the next week or so but I don't see how this would stop the wobble (certainly not on only one side).

The bike does actually run pretty well but it still bugs the tar out of me. My bigger issues are more jetting related than ignition. I'd just like to get everything else set as tight as possible before tampering with the carbs in any significant way.

thanks again

Just out of curiosity, with the strobe clamp on #1 plug wire versus #4 plug wire, does it do the same?

Possibly a bad plug wire or spark plug...