Engine Problems (Not running on all cylinders???)

[Mgriz]

So I finally mustered up enough motivation to figure out what the problem was... Now i'm just very confused so any help would be appreciated.

Upon further inspection I found that cylinders 1 & 4 were not firing but 3 & 2 were. I checked the coil and its fine, cam timing is good, but my dyna-s was not firing the 1-4 coil correctly or at all... I checked with a multimeter and I'm getting battery voltage to the coil all the time no matter where the magnet is wrt to the 1-4 module. I also checked the 2-3 coil and it appears that the switch module on the dyna-s is working correctly. I'm not really sure whats going on to make one switch work but the other stay open. The dyna-s instructions say that it could be a bad ground on the timing plate or the module is not getting power. But since one is working perfectly the ground must be fine and they both get power from the same source/wire... Any ideas, I suppose the module could be bad but I wasn't able to find any stories of this happening to other people and its only been on the bike for roughly 700 miles. Thanks for any help you can give me.

[chef1366]

I remember a thread by earlfor saying he had this problem with a dyna-s. He had to send it back and they fixed it. Send him a PM and he'll be happy to fill you in. I'm working on a pretty fouled memory.

[Mgriz]

Thanks guys, it was the Dyna-S. Luckily I had an extra dyna-s laying around that the previous owner pulled off a junkyard bike. I threw that on, set the timing and it started right up... Not that I hold anything against the dyna-s but it is kind of ironic that a component I put on the bike to make it more reliable with less maintenance actually stranded me miles from home.

[Mgriz]

So I finally got around to moving the bike since putting the old (but working) dyna-s in it. Been busy with a new job and house purchase. Anyway, I got about 2miles down the road and I'm assuming the same thing happened. Lost almost all power, so I limped it back to the apartment and I'll be trailering it to my new home... My questions are

1) What would cause two Dyna-s switches to fail?

2) The battery is kind of weak but that should be effecting this, right? I'm assuming that again its only running on two cylinders b/c one of the magnetic switches is malfunctioning.

I'm loosing my patience with this bike as its starting to look like its never going to be back running at full steam... Any help would be appreciated

[49er]

So I finally got around to moving the bike since putting the old (but working) dyna-s in it. Been busy with a new job and house purchase. Anyway, I got about 2miles down the road and I'm assuming the same thing happened. Lost almost all power, so I limped it back to the apartment and I'll be trailering it to my new home... My questions are

1) What would cause two Dyna-s switches to fail?

2) The battery is kind of weak but that should be effecting this, right? I'm assuming that again its only running on two cylinders b/c one of the magnetic switches is malfunctioning.

I'm loosing my patience with this bike as its starting to look like its never going to be back running at full steam... Any help would be appreciated

You could determine if it is the Dyna S by reverting back to the points set up as a trial. That's assuming that you still have them and want to bother re-fitting them.

[txironhead]

Is it possible that your regulator's gone out and is frying your electronics? Is the hot wire to the Dyna fused? I'd contact Dyna and see what they suggest, possibly when they take yours apart they can tell you what happened to it.

[Mgriz]

Alright, so after an embarrassingly long time of the bike sitting in my garage collecting dust. I decided to make an effort to get it back on the road.

I bit the bullet, replaced the rectifier and regulator with a new single R/R piece and purchased another Dyna S. I went though what was left of the electrical system and got rid of a mess of nasty wiring the bike had from its previous owners and cleaned the carbs again. I got out my trusty multimeter and checked the ignition system thoroughly. Everything is within spec and timing is right on so I was feeling pretty confident.

Didn't work out so well. It sounds worse than it did before and that's because its still running on 2 cylinders. Except now its only firing on 1 and 2! I guess I'll check the compression in 3 and 4 tomorrow, not sure what else could be going on. All spark plugs are relatively new, new wires, new coils, new carb boots, etc. Any ideas?

[49er]

Alright, so after an embarrassingly long time of the bike sitting in my garage collecting dust. I decided to make an effort to get it back on the road.

I bit the bullet, replaced the rectifier and regulator with a new single R/R piece and purchased another Dyna S. I went though what was left of the electrical system and got rid of a mess of nasty wiring the bike had from its previous owners and cleaned the carbs again. I got out my trusty multimeter and checked the ignition system thoroughly. Everything is within spec and timing is right on so I was feeling pretty confident.

Didn't work out so well. It sounds worse than it did before and that's because its still running on 2 cylinders. Except now its only firing on 1 and 2! I guess I'll check the compression in 3 and 4 tomorrow, not sure what else could be going on. All spark plugs are relatively new, new wires, new coils, new carb boots, etc. Any ideas?

You say that you have now checked out the ignition system thoroughly and yet it is still not running on 2 cylinders. Worse still the problem has moved from a likely coil problem on 1&4, to cylinders 3&4 not firing. Both 3 and 4 are fired on different coils, which means you either have a crook set of leads to those plugs, or your carbs are the problem. How have you established that 3&4 are not running? Is there no spark, or are the pipes just cold? If It's cold pipes, you are likely to have plugged passages in the pilot circuits on those carbs. If you don't have spark, cut back the lead at the caps and reconnect them and try again. Also re-check all the connections at the coils.

Were you working from the correct wiring diagram for your model when replacing the old harness wiring?

[Mgriz]

Thanks for the help... I finally got it running and on all cylinders at that!

Yes, the 3+4 pipes were stone cold... I checked spark and had a nice strong spark for each plug on their respective cables, compression was within spec... so I pulled the carbs.

Sure enough the bowls for 3+4 were bone dry, I had assumed since the plugs were wet and smelled like fuel, the cylinders were getting fuel. Guess they started out that way. Anyhow, there was some green goo under both float needle valves. Cleaned them up and threw the carbs back on the bike and it fired right up. Looks like the electrical work payed off.

Thanks again!

[49er]

Thanks for the help... I finally got it running and on all cylinders at that!

Yes, the 3+4 pipes were stone cold... I checked spark and had a nice strong spark for each plug on their respective cables, compression was within spec... so I pulled the carbs.

Sure enough the bowls for 3+4 were bone dry, I had assumed since the plugs were wet and smelled like fuel, the cylinders were getting fuel. Guess they started out that way. Anyhow, there was some green goo under both float needle valves. Cleaned them up and threw the carbs back on the bike and it fired right up. Looks like the electrical work payed off.

Thanks again!

Good to hear it's running right again. There's no short cuts to cleaning carbs.