Friggin Points

so i think i have more of a problem than simply setting the points. I set the left side, light is lit when points open. move to the right side and with the points OPEN the bulb is lit but dim. (shouldn't) My meter at this points reads 5V, i disconnect the left coil (black yellow) from power and it then increases to 12V or a properly lit bulb. ???????? I know the points on the right side are open as i fully spring it open and i still read 5V????

I have to have a shorted coil... I thought potentially that set of points was grounding to the binding post, but a swap changed nothing. I cannot find anywhere that it is potentially grounding either. but why the hell 5V??

i still can't set that right set of points either. when the AAU is NOT advanced i can fine tune the points to open with the bulb. once i fully advance the AAU there is no amount of CCW adjustment to get them to close. and i did set the left side with the AAU fully advanced.

This is getting ridiculous. You probably are all getting sick of me. Thanks so much ~Gavin

Capacitor failed?

GavinJuice said:

This is getting ridiculous. You probably are all getting sick of me.

Click to expand...

Gavin,
No problem there at all Gavin! Keep those questions coming, as you are sure to figure out the reason why it won't start sooner or later.


As cash said, have you tried swapping over the ignition condensers/capacitors (both should be in a block under the coil bracket next to the ballast resistor)?

If you are unable get enough adjustment range on the points plate to set the ignition timing on both cylinders correctly, then you will probably need to remove and re-position the AA unit slightly.

Are you sure that the points wires are wired to the coils on the correct sides? Having the points wires crossed would put you 180 out in timing no matter how you went about it. Black and yellow and black and white look very close after some years. A new points harness on an old points bike now that's a good thing. Easy to check before you tear it down and throw it across the room.
If you do a search using my handle three years ago I did a full write up on setting up points. It's got about three bikes running that I know of. Check it out under this: http://tinyurl.com/yss7ew

nah the wires are clearly still yellow so there's no problems there. I do think that i am going to have to move the AAU just a smidge so i can get the timing spot on. Just a little bit of advancing moves it too much.

I still need to find out why i am having a 5V reading when the points are open. I will take LAB's advice and swap parts to see if i can recreate the problem on the other side.

Any ideas as to the 5V reading with the points on the right side open, and then 12V when i disconnect the left coil? Thats what's got me baffled.

Bad point wire? I have found many bad solder joints at the ringlet end. And some really brittle black rotted wire near there as well. Badly placed or cracked insulating washer? Loose female spade connector at the coil? More than a few of these.

GavinJuice said:

Any ideas as to the 5V reading with the points on the right side open, and then 12V when i disconnect the left coil? Thats what's got me baffled.

Click to expand...

Yes. The power feeds the ballast resistor then each of the coils. If the left side points are closed you'll read the voltage at the junction of the ballast and the left coil. Should be roughly 6 volts. When you disconnect the left coil you remove the load on the ballast resistor and read 12 volts. You'd get the same result by opening the left points.

When properly timed and gapped, the points cam closes and opens each set of points separately. Only one set should be closed at any given time. The voltage across the open set will be 6 volts. Only when both sets are open will you see 12V across them.

fantastic explanation, it makes perfect sense now.