Needs jumper wire to run

[Mont]

The only way to start my '78 xs11 is to jump from hot to the red/white wire on the solenoid, then push the starter button. Then, if I remove the jumper, the engine quits. Also, its missing real bad. I suspect the two are connected. Anyone have any ideas where I should look? I'm thinking the ignition switch or a bad connector in the wiring harness.

[randy]

Ballast resistor is fried or disconnected. It's under the tank, left side. The miss could be lots of things. Loose connectors, bad coil, bad plug wires, fouled plugs, pickup coil wire broken, carb trouble. Replace / connect the ballast resistor, then check spark and fuel for each cylinder. Tell us what you find.

[Mont]

Thanks, Randy, I'll check the ballast resistor.
The reason I think the two are connected is because they both came on about the same time. I took the bike out and put a few miles on it the other day, the first time its been run in about 10 years. It ran good some of the time, missed and backfired a little the rest of the time. Then the next day, it wouldn't kick the starter in. I jumped it after some checking around and it ran about the same. Then the next day, it missed real bad. The bike is new to me, so I've got some education in store for me.

[CatatonicBug]

the first time its been run in about 10 years.

If that's the case, you are guranteed that you will NEED to get into the carbs. I'm surprised it even started! Even after 1 summer of not running, the fuel will turn to muck in the carbs and will need to be cleaned out. Not a big deal, but super important for getting these bike running right.

[Mont]

I went through the carbs and a few other things. Cleaned up electrical connections here and there. The engine was froze up when I got it, but after soaking and working it for a few days I got it loose. I'm hoping the rings will seal better, there is a considerable amount of blow-by right now. I put a new battery in it, cleaned the starter button, light switch and kill switch. I also had to clean the gas tank and screens and put new filters on it. Little by little, its coming together.

[CatatonicBug]

I went through the carbs and a few other things. Cleaned up electrical connections here and there. The engine was froze up when I got it, but after soaking and working it for a few days I got it loose. I'm hoping the rings will seal better, there is a considerable amount of blow-by right now. I put a new battery in it, cleaned the starter button, light switch and kill switch. I also had to clean the gas tank and screens and put new filters on it. Little by little, its coming together.

Sounds good. Much like most of the bikes talked about on this forum. Take it slow and read everything you can get ahold of about these bikes. The tech tips are invaluable.

[Mont]

I removed the ballast resistor and checked it with an ohm meter. It goes right to zero, the same as when I touch the two meter probes together. It has "1.6 K ohms" printed on it, so I'm guessing it is bad.