intermittent spark

[AdminGuy]

intro: I was refitting dash the other day and shorted out the
battery a few times. I have a breaker on the battery.

I'm now getting intermittent spark. Which is really fustrating.
Plugs laying on top of heads. Would like to compare readings to
a simular system.

12V Coil tests good. 350ohm

Have exciter to alternator unhooked(draws 0.5V). I'm using the home
built transistorized ignition kit. (this just cleans up and sharpens the signal, still use points)

12.5 V at batt.
7V at dist. (is this correct for this system?)

have checked hi-tension leads. Used dilectric grease on
connections. have bent up hammer head rotor connection a little.
This may be the problem. Not sure.

So,,,,, I may have fried the the trans ign. modual or may need a
stronger battery, or the rotor button is not making contact?

[Kojack]

Don't know too much about transistor ignitions. I'm still trying to figure out vacuum tubes. That said, I've never known one that couldn't get by on about 9- 12 volts so that should be OK. Better clean the points before you do anything else. The coil will fire every time the points close. The rotor and cap distribute it to the proper plug so you can eliminate the rotor and just check the coil lead direct through one plug. Still weak spark? Try it without the electronic stuff. Some electronic ignitions can be damaged if you test for spark without a plug. Oh yeah, you did try jumping out that circuit breaker didn't you? Might have been damaged in the short.

[AdminGuy]

Thanks Kojack- you're right on the money.

A long discourse with Alan Cambell on the VI helped me alot. His key phase for me was "delicously simple system". I tend to over complicate things. So this is what I discovered.

Points open and close but my meter is not getting blown sky high when hooked to main hi tension. So coil not putting out. I had wrong coil (plugs foul -not hot enough). Needed non-resistive. New coil installed. Points need to be tested. Continuity test with resistance. They were not in fact closing. Oil mist I guess had soiled points. A light sand w/ emery and a clean with brake cleaner. Not I've got nice open and close contact!!!! Ahhhh relief.... what the heck do I know. Nothing obviously. Live and learn!

Well I do know that a hammer head rotor (with extended dwell) does smooth out the idle. You can cut a cap in half to repostion the spring button on rotor. neat trick - thanks Alan. The NAPA rotors have a really stiff spring steel which seems to be digging into the carbon button contact. A half cap would allow you to adjust this so it's just right.

Well the coil current collapsing (electromagnetic field collapsing in coil when points open) and inducing hiV AC is putting out a whopper now. The rubber boot was off coil and it shorted to ground 2"!! Now that's a hot spark baby! Big ol' lightning bolt!

I have a spare elect. ign. kit now if someone wants it. It cleans up and sharpens the signal that is sent to the coil. 20 bucks. saves points. ie. a lower voltage passes through points - greatly extending the life. Eliminates the condenser/capacitor from side of dist. is all. Mounts up real nice and out of sight under battery tray.

Alan suggested putting a plastic disk between rotor and points- like modern dist. So I'm trying that, (milk jug plastic) and also will experiment with drilling a breather hole in the cap. Oh ya, and I put an (ND)alternator on the bike. It works really well. I'd really like to replace this all with a mag someday. Mags are cool. So simple. And yet -so expensive when needing to be rebuilt and rewound to work like new.

I'll tune the hi speed adj. on carb and should hopefully see some BIG running improvements in this little 45 scout. Putting it all back together tonight. The timed electronic cleaner/capacitor really kicks butt.

Plugs gapped out to 0.060 - thanks again Alan! Thats a little wider than stock.

Thank-you very much for your help Kojak! Take care.

[Kojack]

I re-read my first answer and saw my mistake. The coil does indeed fire when the points open, not close. I've field tested coils by connecting the terminals to a battery. the coil will spark when the connection is broken and the electomagnetic field collapses. You need a spark plug connected to the coil's high tension lead and grounded to the coil case when you do this. Of course, it doesn't tell you how hot the coil is, only that it works. A nice whiteish blue spark is a good sign of a hot one. Glad you got it sorted out.
By the way, a friend once told me that if his points acted up on a ride he would rub a dime between the contacts, worked every time. I guess rubbbing anything between oily or burnt contacts would help.