no power?

[COxs11newbie]

Just ran in to a problem, and I was hoping to get a little help with this one. I have a 1980 MNS and up until a few days ago it was running just fine.

I've had the bike for about a month, and when i first got it it ran like crap. Completely cleaned the carbs, then it ran perfect. Ran great for a few weeks, then started having a hard time starting, running on only three cyllinders, and eventually not starting at all.

Now I was out this morning working on it and pulled the air filter so see if it would start with no air restriction. Pulled the air filter went to start it, and nothing. No power at all, the neutral light won't even come on.

Checked everything I can think of, fuses, hidden fuse, battery charge (12.8), tip over thinggy, and shorted the solinoid. When I shorted it it turned over and the neutral light came on dimmly.

I put it back on the charger and will test it again later. I'm sure I have more than just a few problems here, but I think I need to fix the power problem first!

Thanks in advance, sorry for the length......

[skids]

It is possible to have a bad key switch. What do you get for volts from the starter button to the solinoid as you press the button (I think between the contact and a good ground)? Maybe there just isn't enough current (because of low volts) to operate the solinoid. If you jumpered the solinoid, you activated the starter, but there may not have been sufficient ignition voltage. If you jumpered the solinoid and the starter turned slowly, the battery was not in a healthy state (or the jumper was not good enough). The charge status does not tell you enough about the battery's health. That kind of analysis takes a load test, like checking the battery volts from terminal to terminal while hitting the starter. If you see the volts fall quickly below 9 volts while doing this, the battery capacity is diminished and when you measured "resting" volts above 12 v, it was just a "skin charge."

Also check the ground from the negative terminal and the frame. It can get corroded and lose contact. There is a ground strap between the front of the battery box and the middle gear housing that is worth checking as well.

[COxs11newbie]

Thanks for the reply skids. I will do those tests as well, but I think it must be something else. The bike turned had juice and turned over strong, then literaly five minutes later nothing.

Is there anything I could have screwed up that would kill the power that quick? All I did in between when it had power and when it didn't was remove the bottom half of the air filter!

[skids]

Once I was trying to start one of mine (I have three xs11s and a parts bike), and I had plenty of cranking power untill all of a sudden it sounded as if the battery died. The battery failed suddenly. I was told by my electrical guru that batteries can develop an internal short. You can use jumper cables to a car battery, but do not have the car engine running. I use the wingnut for the kickstarter bracket (78E) as a ground and I shove back the rubber boot covering the positive lead from the battery at the solonoid post. I once had a battery that was so dead, the bike could not be jumped from another battery until I removed that bad one and jumped the bilke with the loose terminals!

[COxs11newbie]

OK so on a whim I went and bought a new main (secret) fuse, and guess what, power!!! The bike turned over just fine, but still no start.

The battery charge dropped to around 11 v when cranking, is that normal? The bike still won't start, however. I pull the spark plugs and I'm getting a nice spark, and the plugs seem to be a little wet with gas.

I put my hand over the air horns however, and it didn't feel like it was pulling much air through.

What do you guys think, should I tear apart the carbs again?

[COxs11newbie]

I'm still having trouble with this, anyone have any ideas?

I checked the resistence between the spark plug wires for the respective coils, and I was getting around 25k ohms. I've read it should be around 15 correct? It looks like I'm getting a pretty nice spark from all plugs though.

Sorry for the repost, but I can't get this one figured out myself and electrical is definatly not my strong suit. Thanks for any help...

[COxs11newbie]

Also, just checked the 4 pin plug at the CDI box for the proper ohms value, and read about 730 ohms. That's close to normal, if I remember correctly.

Just got a new seat cover, and I want to ride this thing!!!!

[skids]

Add in the resistances of the caps if you are doing the test with them connected. Mine are about 5000 ohms each, I think.

Originally posted by COxs11newbie


I checked the resistence between the spark plug wires for the respective coils, and I was getting around 25k ohms. I've read it should be around 15 correct? It looks like I'm getting a pretty nice spark from all plugs though.