Running on one cyclinder....

[spadesluck]

Sorry for the misspelled title...

So right before leaving work to come home the bike started acting up. Was backfiring through the pipes crazy and way down on power. The tach would go up and down like crazy and the bike would lurch forward. So I limped it for about 15 miles before out of the blue the bike started running on both cyclinders again like nothing happened. However running stop and go the bike starts to backfire some through the pipes, nothing through the carb.

Any ideas?

Stock everything except V&H pipes. 19k miles

 

[stlmikie]

Almost sounds like a poor connection somewhere. May take a look at the wires going into the coil to make sure they are in good shape. The back fire through the pipes would be the unburnt fuel comming from the non firing cylinder being set off by the firing cylinder. Make sure your plug wires are in good shape and connected well. Some people zip tie the wires around the boot to the coil so's they stay a bit better.

 

[woodbutcher]

a little deeper, could be some carbon lodged between the exhaust valve and the seat keeping it open.

 

[spadesluck]

Ok, so i check the coil ohms...
yellow --> red 3 ohms
yellow --> blue 7 ohms ( i beleive this is not good)
red --> to spark plugs both where 10 ohms

I beleive that 7 ohms on the blue side is my problem cause it should be around 3 correct? Thoughts?

 

[DRBarnhart]

With the coil disconnected:

1. red to yellow = 3 ohms
2. red to blue = 3 ohms
3. red to front spark plug socket = 11K - 12K (approx.)
4. red to rear spark plug socket = 11K - 12K (approx.)

Make sure coil connections are good and clean while they're off...

Dennis

PS Yellow to blue is giving you the total of #1 and #2.

 

[BigDogNZ]

I had this twice on my 2000 Vintage Classic. First time was a loose spark plug cap and plug following a service. Yes I spoke to them about it. Second time it was one of the wires broken in back of the ignition switch. Thought I was near out of gas and limped 35 ml back of Wyoming til I could borrow some gas. Didn't fix it so went looking and got lucky. Mainly because BD had already replaced 3 switches under warranty cause they fell apart - so I thought to look there first up and sure enough. Too much accelerating I reckon.....

 

[BigDogBro1]

Check your battery....connections and charging system.

 

[BadBrad]

If a locknut on a pushrod becomes loose, you will get the same symptoms, but it would not fix itself and start running right again. If the symptoms of backfiring, loss of power and loss of one cylinder remained constant, that's what I would look for. If it all of a sudden starts running like it should, then these guys are right about looking for a bad wire.

 

[spadesluck]

With the coil disconnected:

1. red to yellow = 3 ohms
2. red to blue = 3 ohms
3. red to front spark plug socket = 11K - 12K (approx.)
4. red to rear spark plug socket = 11K - 12K (approx.)

Make sure coil connections are good and clean while they're off...

Dennis

PS Yellow to blue is giving you the total of #1 and #2.

A bit late but thanks.

Here are my readings:

1. red to yellow = 3.5 ohms
2. red to blue = 3.5 ohms
3. red to front spark plug socket = 10.2
4. red to rear spark plug socket = 10.2

All the figures are off. What do you guys think?

 

[reloaderbmg]

how about start with the simple shit!!!
new spark plugs!

 

[DRBarnhart]

A bit late but thanks.

Here are my readings:

1. red to yellow = 3.5 ohms
2. red to blue = 3.5 ohms
3. red to front spark plug socket = 10.2
4. red to rear spark plug socket = 10.2

All the figures are off. What do you guys think?

Looks to me like all the figures are within a reasonable tolerance if I'm right about the "10.2" really being Kohms. But, if you're SURE it's 10.2 ohms, your coil is shorted.

Dennis

 

[2000 wolf]

Mine did that. Ended up being a bad spark plug.

 

[spadesluck]

I do have new plugs but the old ones did not look bad at all, either way it will not hurt. I checked the coil a few times with the same readings every time. I hope its just a plug, as I hate intermittent electrical problems

 

[spadesluck]

New plugs did not solve the problem. New coil in my future maybe? Where does the coil wires run to? I can not tell with them going under the tank.

 

[spadesluck]

Nevermind, used common sense. Found my problem as well. The blue wire near the plug is just about broken through. Fixing it now.

 

[Five Five]

is it fixed ?

 

[stlmikie]

That's exactly what happened to mine.

 

[spadesluck]

is it fixed ?

Yes it is, the blue wire coming off the ignition box was broken near the connector. From the condition of the wire it happened over time because it hard burn marks around it from arcing. Did not hurt anything else thankfully.

 

[Slick-Dog]

I just love happy endings.. LOL