Running on one cylinder?

[iandunn]

I haven't ridden for a few weeks because of bad weather and I was waiting on some air filter oil for my new air filter. I got the oil today and installed the filter. Last week (while i still had the old air filter on) I had unhooked the spark plug cables to check the plugs because the bike wasn't starting (hadn't been ridden for 4 days because of weather, so could have been the battery), and forgot that one was still disconnected and tried to start the bike. Now that I've got the new filter on (and the battery fully charged) she started and runs fine, but does sound a little off. The speed/RPMs seem the same as before, but I'm wondering if she's only running on the right cylinder (the engine is louder on the right side than on the left). The left plug cable was the one that was disconnected when I tried to start it, did that fry the spark plug (wasn't grounded or something)?

If so, what kind of wrench do I need to unscrew the plugs? I've got an adjustable one but it won't fit.


Thanks

[cernunos]

I believe you need an 18mm deepwell and ratchet. Love the Baby GS, Pakistan (nuke capable now?), and this forum.

C......

[GRU]

i did the same thing a year ago....time for a new coil  :guns:

[Kerry]

If so, what kind of wrench do I need to unscrew the plugs?

I believe you need an 18mm deepwell and ratchet.

That works great, but I favor a regular 18mm combo wrench.  In fact, I carry one in my tankbag ... but mostly to nudge the oil filler cap open when the engine is HOT and I want to check the oil.  (I also carry a rag to put between the wrench and the cap, so I don't take the paint off for no reason.)

[cernunos]

Come to think of it, I believe I used an 18mm box-end the last time I looked at the plugs. I remembered "18" and I just said "...socket and...". I don't even know if a deep-well will fit in there. Love the Baby GS, Haiti (boy, do those people have it rough), and this forum.

C........

[scratch]

I had unhooked the spark plug cables to check the plugs because the bike wasn't starting, and forgot that one was still disconnected and tried to start the bike. The left plug cable was the one that was disconnected when I tried to start it, did that fry the spark plug (wasn't grounded or something)?

It would not have fried the sparkplug as it was not connected completing a circuit. It may be fouled. But first, did you reconnect the sparkplug cap to the sparkplug? Fire it up and see how it runs. Maybe remove the sparkplug from the head, plug it into its cable, ground it and see if it sparks. If it sparks, the coil is good (er, resonably so, depends on how strong the spark is).

[iandunn]

I checked the plugs and they're fine, I think it was just switching from a fabric air filter to a foam one that made things sound so different. I got an 18mm combo and its working fine. Thanks

[Church6360]

18 mm deep works also, i used it this morning.

[Briggs]

No running cacti?

[12thmonkey]

i did the same thing a year ago....time for a new coil  :guns:

*THREAD REVIVAL*

Is it possible to ruin a coil by starting and idling the bike with one of the plug wires disconnected from the plug?

Because i've done that...twice. Once was about 2 weeks ago. And today, on my way home my bike started acting crazy. It would idle fine (both cylinders firing) and rev ok (not great, but ok)...but as soon as i would start moving, the engine would drop down to only one cylinder. It would run on only one, unless i revved the motor really high 7-9k...then the 2nd cylinder would kick back in. But at any steady rpm, the bike would jolt as the 2nd cylinder went through bursts of firing and not-firing. The suspect cylinder happens to be the one that i left the wire unplugged on...twice. i haven't had a chance to check the plugs...and i'll check the coils by the advice in this thread when i get a chance. But i just wanted a heads up if anyone knew what it might be. Thanks in advance!

[ducati_nolan]

When I change my plugs, I'll check for a healthy spark by holding the plug against the head and tapping the starter button while leaving the other cylinders plug wire hanging. I never thought that I could screw up a coil that way  I guess that I'll stop doing that. You know what they say 'if it aint broke...'

Thanks for bringing that to my attention 

[MarkusN]

If the insulation is already weak, that can happen, yes. Lacking the controlled gap of the spark plug, the electrical energy searches the next convenient outlet. That can create flashovers anywhere in the circuit where the insulation is already weak. The resulting burn marks can permanently damage the insulation.

[gsJack]

....................but I'm wondering if she's only running on the right cylinder (the engine is louder on the right side than on the left). The left plug cable was the one that was disconnected when I tried to start it, did that fry the spark plug (wasn't grounded or something)?
Thanks

Doubt if that could cause any damage, I've done a fair amount of miles on half of the cylinders.

Two of the plugs stopped firing on my 85 Nighthawk 650 once, the bike I traded in on my 1st GS.  I rode it home about 30 miles mostly on level ground, uphills were a Buddha Loves You.  Turned out to be a loose primary wire on one of the 2 coils.  Plugged in the wire and it ran good as new again, would have pulled the tank and fixed it on the road if I had known how simple the problem was.

Was having trouble with one cylinder cutting out on the 02 GS this spring in wet/damp weather a couple times.  Cyl came back in after a few miles and then one morning I started it up and it was running on only one cyl at home in the garage at start up.  Pulled the tank and only thing I could find was the spark plug wires were a bit loose in the coils, screwed them down tight and no problem since in all kinds of wet conditions.  My garage can be very damp and some mornings there is heavier dew on the bike in the garage than on the cars outside.   

Making it home on one cyl on my old CM400A winter bike was a way of life on a rainy day for awhile.  One plug was cutting out due to water in the hollow style plug cap due to a worn seal.  New plug caps fixed that one.  A frequent problem on old Hondas.

[MarkusN]

Two of the plugs stopped firing on my 85 Nighthawk 650 once, the bike I traded in on my 1st GS.  I rode it home about 30 miles mostly on level ground, uphills were a Buddha Loves You.  Turned out to be a loose primary wire on one of the 2 coils.  Plugged in the wire and it ran good as new again, would have pulled the tank and fixed it on the road if I had known how simple the problem was.

Since the primary was not connected, there would be no high voltage load on that coil, so no risk to break down the insulation and shorting out the coil.

Was having trouble with one cylinder cutting out on the 02 GS this spring in wet/damp weather a couple times.  Cyl came back in after a few miles and then one morning I started it up and it was running on only one cyl at home in the garage at start up.  Pulled the tank and only thing I could find was the spark plug wires were a bit loose in the coils, screwed them down tight and no problem since in all kinds of wet conditions.  My garage can be very damp and some mornings there is heavier dew on the bike in the garage than on the cars outside.   

This one might have been a hazard to the insulation, but most probably the path over the loose wire and the spark plug gap was sthill the shortest, just weakening the spark.

Making it home on one cyl on my old CM400A winter bike was a way of life on a rainy day for awhile.  One plug was cutting out due to water in the hollow style plug cap due to a worn seal.  New plug caps fixed that one. A frequent problem on old Hondas.

This one would be a short for the high voltage pulse, keeping its voltage down. Again, no risk to the insulation.



But, yeah, if running the ignition with one spark plug disconnected was really that much of a hazard as the MC makers sometimes make it out to be we would hear a lot more about this kind of problem. Spark plugs have been disconnected thousands of times and the engine cranked over without doing any damage to the ignition circuitry.

[12thmonkey]

I rode it home about 30 miles mostly on level ground, uphills were a Buddha Loves You.

Yeah, i rode home about 10 miles in LA rush-hour traffic. i know having too much power claims the lives of plenty of squids each year...but being grossly underpowered is far more dangerous. Probably one of the scarier rides i've had.

i'll check the connections at the coils when i get home tonight. It seems like a loose wire could definitely cause that cylinder to fade in and out...but would that explain it being connected to the load on the engine or the RPMs? Cause the bike idles on both cylinders, and will run temperamentally when i rev it high...but when there's a heavy load on the engine as in starting off...it drops down to one cylinder. Any thoughts?

Thanks for the help so far.

[12thmonkey]

Any other thoughts? i'm about to head home and start looking into stuff. i have the general idea about checking spark and swapping coils if one is suspect...but if there is anything else anyone can think i should check, i'd appreciate it.

[12thmonkey]

Ok...just came in from outside. First off, i pulled the plugs and checked them. They both were a little white...but not too bad. Next, i reconnected them to the wires, and held them one at a time against the cylinder head while i thumbed the starter. The first i tried was the bad cylinder, and it had what i thought was a pretty puny spark. Then i tried the other cylinder...same puny spark. i guess it turns out that i had a little unrealistic expectations about how big the spark would be. So, both seem to be getting a decent spark. While i was hoping i'd find a problem here, i wasn't surprised that i didn't. Since the bike seems to idle fine with both cylinders...i figured that initial spark would be good for both. Then i pulled the tank, and checked the connections at the coils. i could see how the plug wire screws in to the coil...it just seemed to kinda come out of it. i checked the connectors of the smaller wires, and they seemed clean and making good contact. So, now i don't know what to do...any ideas of what it could be? It's my only means of transportation, and i really don't want to have to take it to a mechanic...and don't honestly even have the time to. Any help would be greatly appreciated. In case you skipped to the last post...here's what i initially posted:

i did the same thing a year ago....time for a new coil  :guns:

*THREAD REVIVAL*

Is it possible to ruin a coil by starting and idling the bike with one of the plug wires disconnected from the plug?

Because i've done that...twice. Once was about 2 weeks ago. And today, on my way home my bike started acting crazy. It would idle fine (both cylinders firing) and rev ok (not great, but ok)...but as soon as i would start moving, the engine would drop down to only one cylinder. It would run on only one, unless i revved the motor really high 7-9k...then the 2nd cylinder would kick back in. But at any steady rpm, the bike would jolt as the 2nd cylinder went through bursts of firing and not-firing. The suspect cylinder happens to be the one that i left the wire unplugged on...twice. i haven't had a chance to check the plugs...and i'll check the coils by the advice in this thread when i get a chance. But i just wanted a heads up if anyone knew what it might be. Thanks in advance!

[12thmonkey]

Anyone? i'm clueless what else it could be and don't have hardly any time to work on it...or even get it to a mechanic. Any help would be very, very appreciated.