Right cylinder firing less than left

[irk_miller]

I think the 2.8 ohm reading is caused by, when having the wires all connected, you are actually getting a reading of 2 coils, that are connected in parallel, due to the +12 leads on the coils being connected together.

Your meter is measuring the circuit between the two leads, which in this case is the primary coil of one coil.  It doesn't matter what's going on behind the leads.

[Dvsrd]

I replaced the left coil. It had 4.4 ohms before I installed it. After installation, I rechecked it. The coil showed showed only 2.8 ohms. I checked the other side, 4.4 Ohms on the right side. Then I unhooked the orange wire on the left side coil, it showed 4.4 ohms. I then turned the ignition on, and checked the left side coil again. This time it showed -1. The coil was getting voltage from the battery on the left side. The right side was fine, it showed 4.4 ohms. I was checking the connections by the battery, and happened to put my hand on the left coil. It was noticeably warm! The left coil is getting voltage from the battery, and going through the system and heating up the coil. I'm surprised it occasionally fired at all on the left side. Has anyone ever experienced anything like this? The problem must lie with the rectifier, the voltage regulator, or somehow the generator.

The change in measured resistance is because when connected, more circuitry is involved. So that 2.8 ohm value is irrelevant or misleading. What IS relevant, however, is the condition of wiring, connectors and switches between battery and coil +. AND the condition of wiring, connectors and breaker points on the coil negative side. Basically, with the condenser/capacitor disconnected, everything else connected, ignition and kill switch on and the points closed, there should be minimal voltage drop from battery to coil +, and minimal voltage drop from coil negative to ground. Or put differently, very close to 12.6V between coil + and coil negative. This is a very basic but important check for all battery powered points ignition systems.

[Dvsrd]

And one more thing. With a healthy and fully charger battery, the bike shold run fine for at least half an hour even without an alternator.  So forget about the charging system until it runs like it should. Many roadrace bikes ran "total loss ignition" back in the day, without problems. They just fitted a fully charged battery before practice, then swapped it for another before the race.

[Dvsrd]

The image in my next post is the basic circuit for one coil/ set of points. I have tried to indicate where to measure voltage, with points closed and ignition+ kill switch on. This relates to my earlier post on checking for good continuity and minimal voltage drop.

[Dvsrd]

[Super Dave]

I have found the best way to clear out a bike that is loaded up is to remove the plugs, ground them on the head, turn the gas off, choke off, and ignition off. Put the bike at the top of an incline, put it in first gear, and push it with the throttle wide open. 100 or 150 ft should do it. Sometimes you can see the gas spraying out in a mist. Put the plugs back in, and it'll usually fire up. The reason I was getting 2.8 ohms on the left coil, was because the points were closed. If I opened up the points, (with the ignition on) it would jump back up to 4.4 ohms. I bought some B7ES spark plugs, they are the only ones that the bike will not foul. It was still running mostly on the right cylinder. I then took the generator off, to check the wires. Everything seemed to be fine until I spied a condenser wire (for the left cylinder) that appeared to possibly be rubbing against the generator housing. The insulation looked to be somewhat flattened (on one side) almost as if it was abraded or possibly partially melted. There was no indication of arcing on the generator housing. It didn't look too bad, but enough to be suspicious. So I insulated the wire, and put the bike back together. On the bench when I fired it up it sounded fine, so I took it on the road to put a load on it. I rode it for about 10 minutes, the left side didn't cut out at all. Other than the carbs being somewhat out of sync, it ran gangbusters! So hopefully it looks like with some minor adjustments and I'll be good. I am kind of concerned about using B7's, as it is a hotter plug. I also turned the oil pump as lean as I could get it, I'll do a plug check later when I get some time on it. Is anyone out there using B7's?? In addition, I would like to thank all of you for your time and advice. With a little luck I'll be race ready for this  spring.

[m in sc]

that def sounds like it. side note dont run 'E' series (3/4") reach plugs on a 350, the need to be b8hs or similar, 1/2" reach. and.. good job on finding it