Timing light for kz750

loudhvx wrote: Going more advanced than the double lines is risky since that can promote knocking. Maybe someone with racing experience will know if it's safe or not on your motor. I suspect not.

Being slightly after the F mark at idle might make the idle a little less smooth and consistent, but it should be safer for the motor than going too far advanced at high RPM with high load.

But, really, the ideal thing is to fix whatever is causing the advance to have too much travel.

If I go 1/8" before the F mark it will go between the 2 Lines. I also put the rpms really low and it didn't change the position with the timing light. Which I think would mean the springs are still good.

Am I being too anal? because its really not too far past the two lines.

I do remember last year checking timing and it was dead on. This year I got the valves done, and new rings, and new 3.0 dyna coils.

bountyhunter wrote:

loudhvx wrote:
But, really, the ideal thing is to fix whatever is causing the advance to have too much travel.

Should be fairly easy to fix. On mine there are metal "pads" that limit the travel of the weights. Get some silver solder and solder up some "meat" onto the pads there then file them down to adjust travel distance.

The figure above shows them as "advanced stop".

Would double check again because it is very odd the get too much advance, always see the other way.

I think it should be fairly easy too. I have the advance stops as well. Sometimes with the timing light, when I give it just a little gas I see the advance skip around a little. It happens so fast that I wonder if I'm just seeing things.

But do you have the little rubber idle stops?

If they fell off, then the idle would have been retarded. When you corrected that by advancing the plate, you effectively moved the advance position forward by the same amount. So if the F mark was retarded by 1/8th inch, then you correct to the F mark, the full-advance is advanced by 1/8th inch. That seems like it could be bad news for the motor when you get on the throttle hard, (unless you time it to the double lines and let the idle advance stay off the F mark).

If you don't have the rubber stops for idle (because they fell off) you can compensate by adding metal to the advance stops, as Bountyhunter suggests, to make the arms stop sooner.

Adding metal to the arms themselves would probably be a bad idea since it will alter the advance rate.

Yes I have the rubber stops.

Sorry if I'm not making sense with this. This area is kinda new to me. I turn the dyna-S pickups to the left(counter clockwise) and the mark on the case goes to the left of the F. This will make the mark go between the 2 lines. If I move the mark on the case clock wise, it will increase idle speed but still go past the 2 lines.

Is clock wise retarding? Sorry if I made that mistake.

If the rubber stops are intact, then I'm not sure what would cause the advance to have too much range. Perhaps it actually has too little range as Bountyhunter was suggesting earlier?

Assuming inline-4 motor (crankshaft rotates the same way as the wheels) and timing pointer is at the top window of the timing plate on that motor...

Turning the timing plate (Dyna S pickups) clockwise will retard the ignition. The F and two-lines will appear to move to the right of the pointer.

Turning the timing plate (Dyna S pickups) counter-clockwise will advance the ignition. The F and two-lines will appear to move to the left of the pointer.

If the F mark is left of the pointer, it is advanced at idle.
If the F mark is right of the pointer, it is retarded at idle.

If the 2-line mark is left of the pointer, it is advanced at high RPM.
If the 2-line mark is right of the pointer, it is retarded at high RPM.

loudhvx wrote:
Being slightly after the F mark at idle might make the idle a little less smooth and consistent, but it should be safer for the motor than going too far advanced at high RPM with high load.

Did you mean begin slightly before the F mark at idle? Because this seems to make it stop between the 2 Lines.

bobski911 wrote:

loudhvx wrote:
Being slightly after the F mark at idle might make the idle a little less smooth and consistent, but it should be safer for the motor than going too far advanced at high RPM with high load.

Did you mean begin slightly before the F mark at idle? Because this seems to make it stop between the 2 Lines.

I mean the bike may not idle as smooth if the F mark is slightly to the right of the pointer. This means the bike is firing after the F mark passes the pointer, thus the ignition will be slightly retarded at idle.

If the F mark lines up to the right of the pointer, and the 2-line mark lines up correctly, then the advancer has too much rotational movement, and needs to be stopped down somehow.

loudhvx wrote:

bobski911 wrote:

loudhvx wrote:
Being slightly after the F mark at idle might make the idle a little less smooth and consistent, but it should be safer for the motor than going too far advanced at high RPM with high load.

Did you mean begin slightly before the F mark at idle? Because this seems to make it stop between the 2 Lines.

I mean the bike may not idle as smooth if the F mark is slightly to the right of the pointer. This means the bike is firing after the F mark passes the pointer, thus the ignition will be slightly retarded at idle.

If the F mark lines up to the right of the pointer, and the 2-line mark lines up correctly, then the advancer has too much rotational movement, and needs to be stopped down somehow.

Haha, okay. If the F mark is slightly to the right of the pointer it does run a little rougher. And the pointer will line up between the the 2 lines.

If the F mark is slightly to the left of the pointer it will run a lot higher and smoother, but go past the two lines.

I think we are on the same page haha. What other options do I have other than melting some solder in the stops, as Bountyhunter suggested? Is there something that I could be missing? Valves, cams, timing chain?

Can you take a closeup photo of the advancer? Maybe we could spot the problem.

No problem, I'll do that when I'm done work (few hours). On the bike or off?

Here we go. Hope you see something I'm missing. :silly:

Can you remove the rotor with the magnet in it, and very precisely measure the outside diameter of the stem of the rotor? If that rotor has the wrong diameter, that will alter the amount of movement the arms have. The stem of the rotor is the stop for the idle position.

I will try and find a rotor from a stock advancer for 550/650/750 and see what the diameter is.

Edit: actually, you can measure the diameter without taking the rotor off if you have some calipers to squeeze in there.