Backfire caused by bad coils?

[Wtf_0ver]

Hey all,

Had the GL out yesterday and as I was coming up my driveway it started to sputter and died right before pulling into the garage. I assumed I had run out of gas as my bike is completely stripped down with no fuel gauge or anything. Tank ended up being half full so it wasnt that and I just kind of shrugged my shoulders and walked away.

Took the bike out later that evening to meet friends for dinner and after being on the road for about 20 minutes there were a few instances where the bike started to stumble and lose power while on the throttle. It would backfire through the exhaust and then and pick back up again.

On the way home I took it easy and didn't have any issues until I was close to home where it started doing it again. This time though it was dark out and I noticed my light would flicker and turn off while the bike was hesitating. It would either backfire and come right back to life or it would completely shut off and I'd have to stop and start it up again.

I need to go through the general rundown of testing the battery and make sure it's charging correctly but would this be indicative of a coil going bad perhaps? I've custom wired the entire bike so the light going in and out while the bike hesitates leads me to believe it's something else as the key on means the lights are on regardless of what the coils are doing. The part that baffles me with all of this is the backfire though as I've had loose wiring issues before that caused the bike to run off but never any that caused a backfire.

Sorry for the long ramble. Any thoughts?

[scootsx2]

First off I would check all the connections in the ignition circuit - both the primary and secondary sides. If they are OK and if you have an electronic ignition, it may be going bad. About 5 - 6 years ago I had one go south on me. It started as intermittent misfires when the engine was up to operating temperature. It was hard to diagnose at first because whenever I tried to chase it down, the engine had cooled sufficiently for it to function. It eventually went to full failure. One of the ignition modules had shorted full on.

[gltriker]

"This time though it was dark out and I noticed my light would flicker and turn off while the bike was hesitating."

A "bad coil" won't cause a light to flicker. Go back through the all the wiring and circuits......starting at the battery, itself.
So many problems reported here have ultimately been discovered to be caused by a faulty battery.

[todd54219]

First off, how old is the fuel and did you drain the carbs when you stopped riding last year. Second, check the fuel cap. It might not be venting properly which would restrict the fuel flow. Maybe try running the bike with the cap loose. Also try one fix at a time. If you do several things you may not know what the issue was. Just my opinion.

Todd

[CYBORG]

First off, how old is the fuel and did you drain the carbs when you stopped riding last year. Second, check the fuel cap. It might not be venting properly which would restrict the fuel flow. Maybe try running the bike with the cap loose. Also try one fix at a time. If you do several things you may not know what the issue was. Just my opinion.

Todd

I agree I run my bikes, up to temp, every week, especially in the cold winter months. But if you don't, changing fuel, or adding stable, can make a difference. When you walk away from any vehicle for any amount of time, It is going to take some effort to bring them back. They WILL go bad just sitting. Show them some love year around pays dividends

[jdvorchak]

Check your ignition switch and wiring. The lights going off is a hint. It's like turning the ignition switch off and back on. Often it will backfire by igniting the unburned fuel in the exhaust.

[Wtf_0ver]

Hey all just some updates since I realized my initial post came off as bit of a ramble.

It's not bad fuel as I've been riding the bike for a couple of weeks now and recently synced the carbs again the other day.

The main thing I noticed is that this issue started occurring AFTER the bike had been on and running for 20 plus minutes which would seem to me like some electrical component was failing once the bike was hot. The bike was a custom wiring job by me with a turn key style auto ignition. The reg/rec is mounted in an area where it has PLENTY of airflow. I shook the entire wiring harness and all connections with the power on while the bike was sitting and couldn't replicate a loss in electrical power, lights flickering, etc. What components could fail once hot that could potentially indicate any of the symptoms I've described thus far is what I'm trying to narrow down now.

Thanks in advance.

[Shadowjack]

Had this problem on a 305 Honda that took me months to figure out. Stop when it'd been running 10-20 minutes, worked fine when it cooled down. The condensers were getting intermittent as they warmed up. Not usually a problem on a Goldwing down by the battery, but they're easy to change out.

[wingrider]

You haven't said what ignition you are running, aftermarket, or stock? As far as the backfire, it does sound like ignition problems. You could have a bad coil, or ignition setup...that being if you had an aftermarket, it could be going out on you. If it is stock, then a refresh of points and condensers are a good step, but can't rule out a coil (or wire) just yet either.

[Sagebrush]

When it starts to run rough again open the gas cap, it could be the gas cap vent is plugged and your pulling a vacuum on the tank after running awhile.

[gltriker]

Hey all just some updates since I realized my initial post came off as bit of a ramble.

It's not bad fuel as I've been riding the bike for a couple of weeks now and recently synced the carbs again the other day.

The main thing I noticed is that this issue started occurring AFTER the bike had been on and running for 20 plus minutes which would seem to me like some electrical component was failing once the bike was hot. The bike was a custom wiring job by me with a turn key style auto ignition. The reg/rec is mounted in an area where it has PLENTY of airflow. I shook the entire wiring harness and all connections with the power on while the bike was sitting and couldn't replicate a loss in electrical power, lights flickering, etc. What components could fail once hot that could potentially indicate any of the symptoms I've described thus far is what I'm trying to narrow down now.

Thanks in advance.

#1 Change out the automotive, turn-key style switch.

#2 Also, what's the voltage reading across the battery posts, before, and then, when this issue presents?

[Wtf_0ver]

Hey all just some updates since I realized my initial post came off as bit of a ramble.

It's not bad fuel as I've been riding the bike for a couple of weeks now and recently synced the carbs again the other day.

The main thing I noticed is that this issue started occurring AFTER the bike had been on and running for 20 plus minutes which would seem to me like some electrical component was failing once the bike was hot. The bike was a custom wiring job by me with a turn key style auto ignition. The reg/rec is mounted in an area where it has PLENTY of airflow. I shook the entire wiring harness and all connections with the power on while the bike was sitting and couldn't replicate a loss in electrical power, lights flickering, etc. What components could fail once hot that could potentially indicate any of the symptoms I've described thus far is what I'm trying to narrow down now.

Thanks in advance.

#1 Change out the automotive, turn-key style switch.

#2 Also, what's the voltage reading across the battery posts, before, and then, when this issue presents?

1. That style ignition switch has worked for me for the four years I've had the bike set up that way with no issues.

2. I'll have to check voltage but I've only experienced the issue while the bike is running and under load, I'll have to see if I can replicate it while on and running sitting in my garage.

[gltriker]

Done.

[wingrider]

What bike is this problem on? That might help us as well.

[Wtf_0ver]

What bike is this problem on? That might help us as well.

Sorry it's an 80 GL1100 but currently has an 83 swapped in.

Appreciate all the responses I've gotten so far, will definitely report back once I've done some further and more extensive testing. If there's one thing I have trying to track down, it's intermittent electrical issues.