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Discussion Starter · #1 ·
I am able to get the bike to start, and it even runs, sort of. In neutral, the bike sounds great. First gear, I have power all the way to about 7k rpm. Second gear starts losing power at about 5k rpm, and then each gear starts losing power earlier in the revs. I initially thought something was wrong in the carburetor, but after going through it, I'm fairly confident this isn't the problem.

I've discovered that I have a weak spark. I tested my ignition coil, and according to my repair manual's specs, the resistance was too high in the secondary, and so I replaced it with a new Emgo coil. Now my manual says that with the spark plug boots on, I should only get about 15k ohms of resistance, but that's how much I get with the spark plug boots off. And I've checked the manufacturer's spec on that Emgo coil and it's within the acceptable range.

Standard spark plug boots have 5k ohms of resistance each, and that would mean that by the manual, the OEM coil would have to have only ~5k ohms of resistance itself. I've tested 3 used OEM coils and got 14-18k ohms on each of them, and the shop I was getting them from said they were a working part. I have trouble believing that 3 used coils are that close and bad, and a new part that was designed for this bike is that far off too.

I'm thinking that the Clymer's just made an error, and meant to say with the spark plug boots OFF, not on. I think this because resistorless plug boots seem to be hard to come by, and all custom made for racing applications. Which my bike is not. Now, this still leaves me with a weak spark, and no obvious reason why. (to me)

The battery, rectifier/regulator, ignition coil, points, spark plugs and condenser are all brand new and tested good. The points gap is set as near to perfect as I can get, and I had the bike running in the past, so I know that I'm capable of setting the gap. The spark plug gap is also set. The timing is set. And I can find no obvious loose connections in the wiring, although I have discovered that the wiring is in shoddy shape. (It's been repaired in several place with just electrical tape.)

I've got a new wiring harness on its way, because even if the wiring isn't the issue, I want to fix it up.

Can anyone think of any other reasons why I would be getting a weak spark? Any help is much appreciated in advance.
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