1978 GL1000 Won't Run

[RogueInLA]

Hi, hope someone here can get me in the right direction. Recently purchased a 1978 GL1000, ran fine when I bought it, been riding it for 2 weeks. Yesterday started popping and misfired, then died, but started right up again. Today it started missing, then smoothed out again, stopped at a friends, and it won't start. Well, it'll start, and idle, then suddenly die, or start, idle, I can rev up, then die. I don't know how strong the spark is supposed to be to the plugs, but it looks weak to me. It has a Dyna ignition module. I jumpered the ballast resistor and I have the same symptoms, so I'm guessing that's not it? I put a new battery in when I bought it, and it shows 14 volts when it's running. Could it be the coils? Would both 'die' at the same time? I don't see any loose wires, and I checked for loose grounds, etc. I hadn't done any work on the bike before this happened, other than changing the oil and the fuel pump. The bike has 153,000 miles, PO said he changed the timing belts about 45,000 miles/4 years ago. When the bike ran, it was running fine, good power, etc. I haven't worked on motorcycles in years. Any ideas? Thanks in advance.

[virgilmobile]

It may be fuel starved rather than a spark problem.Filter plugged,vent in fuel cap plugged,poor fuel pressure,etc.

[RogueInLA]

Thought of that, put new fuel pump and filter, the way it just stops is why I'm thinking ignition, shouldn't there be enough fuel in the carbs to keep it running for a minute once it starts? Thanks for the input.

[RogueInLA]

Anyone here familiar with the Dyna ignition? One friend says pull it and put points back on it, cuz they go bad, another says they're bulletproof. If the Dyna was bad, would the bike run at all, or would it do this start die start run die thing? Is there any way to test the Dyna module?

[dingdong]

If it is firing both coils it is working, it is just a switch. However it may have a grounding problem. Some of the Dyna have a problem with grounding. The back plate that is held on by two screw is the ground for the modules. The plate on some are thinner than the ridge where the screws tighten up. I had to put star lock washers under the screws in order to tighten up on the plate properly. Check for a good ground there. Also check the main ground cable where it connects to the frame and engine.

[virgilmobile]

I don't have a schematic,however any electronic device,if improperly installed could overheat and fail.
Once cooled it may work again.

You could go back to points.Personally I prefer any electronic ignition over points due to available spark during cranking and longevity.

The point system uses a large ballast resistor to control current and voltage to the point driven coils. Reversing the wires on the ballast can adversely affect the system.The parts that replace the points assembly are the whole package.
Also look at the voltage going to the modules.If it's low,the spark will also fall off.

If you have the Dyna S system,look at this ...http://www.powercommander.com/downloads ... /DS1-3.pdf

[RogueInLA]

Good news, I think, had the coils tested (good) put them back on, checked all connections and grounds, same problem. Then all the lights went out, and no power at all, while checking the battery connections, the positive cable literally came off in my hand, totally corroded under the protective cover, probably only 3 strands making contact. How it got enough juice to turn the bike over is anyone's guess. Replaced the positive cable and it seems to have fixed it (knock on wood). So apparently the Dyna is still good, thanks to all for their input. Still not perfect, so rebuilding the carbs is next on the agenda.

[78AzWing]

You may want to replace the negative side also.

[Fred Camper]

We all need to remember that most issues are electrical on a good running bike. Folks are often to quick to tear into the fuel system when something electrical is an issue. Glad RougeInLA got this one fixed.

[RogueInLA]

One wierd issue tho, bike runs fine all day, BUT, there's a store on the way home from work, IF I stop at the store, from there to the house the bike is almost guaranteed to just die, pull over and it starts right up. If I don't stop at the store on the way home, just pass by (same route) bike runs fine. Twilight zone?

[Fred Camper]

Where is the fuel pickup when you stop, do you close it or leave it open?

[Fred Camper]

Sorry, meant the fuel petcock, not pickup.

[virgilmobile]

Stop at the store again,loosen the gas cap,do the shopping then secure the cap and drive home.
I'm guessing a vacuum lock in the tank from a bad gas cap.

[sfruechte]

I've gone through at least two ignition switches in 40 years. The rivets on the copper contacts loosen up and make an intermittent connection. Tricky to find. You can get just the plastic piece that rotates the contacts and don't have to buy the whole housing with key etc... The first problem only showed up on left hand turns. The next one gave a clue with inconsistent lighting of the oil light when just the switch was on.

[Maz]

No disrespect, but this post is 7 years old now.....Hopefully he got it sorted!

Maz

[SnoBrdr]

No disrespect, but this post is 7 years old now.....Hopefully he got it sorted!

Maz

Ya know I hate when people ask for help yet never tell us the outcome.

[Maz]

It's one of my pet hates.....Along with people who ask for advice, get 10 responses all suggesting the same course of action and then they ignore it and go their down their own route because "..my mate said".

Maz