Steve Saunders Goldwing Forums banner
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Discussion Starter · #1 ·
Hello all,
I have a '79 GL1000 Goldwing with 48000 miles on it that has a maddening problem. Let me begin by telling you it's service record. This spring, I rebuilt the carbs, installed new timing belts, replaced the points, plugs, and condensor, and set the timing to specs. It was running perfectly.
Monday, my son and I set off on a road trip to Mount Rushmore and the surrounding areas and, after 400 miles of perfect riding, called it a day. The next morning, after another 120 miles, it dropped the RH cylinders anytime it was below 3000 rpm. Once the bike was cooled down, it would run fine again. There is no smoke and it runs fine at road speed. I took it to two different dealerships and after scratching their heads, and various other places, could not come up with a solution. Perhaps the fact that my bike is older than the people working on it had something to do with it. After giving up on the dealerships, I loaded into a U-Haul van and brought it home. The next morning, of course, it started right up and ran fine. Not willing to risk doing any engine damage, I've parked it until I come up with a solution.
Is it possible that I've got a ignition coil breaking down when it gets hot? I'm convinced it's an ignition problem, and the coils, wires, and resistors are the only thing that have not been replaced. Remember, it runs fine when cooled off. Problem only shows up after extended highway speed.
Any help would be greatly appreciated!
Del
 

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Junior Grue
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Welcome to the forum.:claps:

If both right hand cylinders loose power it's unlikely to be ignition as both fronts fire off the same coil as do both rears.
 

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If it runs above 3000 then it must have spark. I am thinking maybe the low speed jets plugged.
 

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Discussion Starter · #4 ·
Hmmm...Not certain that both RH cylinders misfire, but definitely hear "popping" sound in right exhaust when running at 2500. One thing I am sure of is that it is only hitting on two cylinders. When the rpm is raised, then it snorts and bangs and picks up the other two.
 

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Discussion Starter · #6 ·
I would agree if not for the fact that it runs fine when cooled down. Only after extended highway speed (4500 rpm) does it have the problem.
 

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Village Whack Job...
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Check the gas cap vent. It's probably plugged. Which isn't allowing air to into the tank to replace the volume of fuel that leaves it as it's used. This creates a substantial amount of vacuum in the tank, enough that the fuel pump won't feed enough fuel to the carbs. Seeing as how fuel is fed through carb number one then on to the other carbs, it stands to reason that the carbs furthest from the the tank (down the ruel path that is) would be the ones to be starved. Back firing is usually a symptom of a very lean mixture. (of course an overly rich mixture will cause back firing as well)

When the bike is allowed to sit the vacuum in the tank slowly dissipates.

Easy way to eliminate the gas cap as the possible culprit is the next time it acts up just loosen the cap and see if the issue goes away. If it does you've found your gremlin.
 

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Welcome to the forum ChevTech! You may want to ask the moderators to move this thread to the Tech section or perhaps open a new thread there. You may get some more advice from wrenchers who don't haunt this general discussion section.

Oh, and my grasped-at straw for you to consider is to swap the spark plugs from right to left. See if the popping shifts sides. I know you said you put in new plugs, but an occasional bad plug does get past Quality checks.

By the way, how did she run before the tune-up?
 

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Discussion Starter · #10 ·
Before the tune up, it had a "flat spot" between 2000 and 2500 rpm. Carb rebuild fixed that and the rest was precautionary. Thanks for the response!
 

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have you rechecked your point gap?? my 2 cents.
 

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Discussion Starter · #14 ·
Sorry. Fingers went faster than the brain. The points were checked and found to be set correctly. The fuel filter was changed with the tune up. Thanks for the tip on EMGO! I got the rear floor boards from them, but how bad could they screw that up?!!
 

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Honda Guru
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This is sort of off the deep end… but I'm good at that..LOL

Some years back I found a GL1000 that had a similar problem like yours… it would loose 2 cylinders when it got hot. To make a long story short it turned out that one set of points would seize up when the temp got too high and stop moving. No points movement equals no spark.
As your looking AT the points the left side controls the front 2 cylinders and the right side points controls the 2 rear cylinders.
In this case it was the 2 forward cylinders that lost spark and I couldn't vouch why it would be the points malfunction if both right side cylinders quit. But if you have aftermarket points you might just want to check…. anyway.
 

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It aint rocket science
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Hmmm...Not certain that both RH cylinders misfire, but definitely hear "popping" sound in right exhaust when running at 2500. One thing I am sure of is that it is only hitting on two cylinders. When the rpm is raised, then it snorts and bangs and picks up the other two.
Guesses get you nowhere fast.:)

As a first step in diagnosis pull the plug wires off one at a time and see which cylinders are not contributing with no RPM change when off.

The shade tree mechanics way to engine diagnosis:

Will start off on the premise of an otherwise well running and properly maintained engine and has developed a driveability concern. Filters and plugs have been changed at regular intervals. This is a first check of basic systems that anyone can do.

First off is to check the ignition system. With the bike warmed up and idling remove and replace one plug wire at a time from the spark plugs. What we want to observe here is a uniform idle RPM drop when the wire is removed providing no ignition to that cylinder. At this same time we are also testing the plug wires. While slowly removing the wire from plug you will hear a distinct snapping noise of the spark jumping to the plug. It should jump from 1/2-1 inch, this tells us the wires are good with no excess resistance. In rare cases the plug will only fire with the wire partly disconnected adding RPM and is likely due to a fouled plug. Pulling the plug wires can be done at higher RPM's by cranking up the idle screw when needed.

Next up is to remove the spark plugs noting their condition and location within the engine. Note the condition of the plugs below which were taken from my 1500 when acquired with no driveability concerns except a release start type of turning over. Plug gaps were on the wide side. These could have been original twenty two year old plugs as the bike had only thirty thousand on the odometer and I was still going through it with frequent starts and idling. Note the two inner plugs (cyls.3&4) look like they have been running slightly hotter or leaner than the others. This is due in part because inner cylinders on an engine will typically run hotter than the ones on the corners. Note these same cylinders are the ones the vacuum hoses are attached to in the runners which could also contribute to the slight difference. All white or all black plugs on one side usually indicate carburetor problems. If you suspect a bad plug you can swap it with another and repeat to see if the problem follows the plug.

When pulling plug wires and none to little RPM drop we must then find if it is lean, rich or compression related. A compression test is always recommended on an unknown or new to you ride.
 

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Discussion Starter · #17 ·
Okay, this is weird! My computer AND my "Old Wing" both died, but the computer has been brought back to life.
Still convinced that it has an electrical problem, I ordered a set of coils, wires, and resistors for it. These were the only parts in the ignition that had not been replaced. After sitting for 10 days waiting for parts (a first for this bike), I installed the parts and fired it up. White smoke came from the RH pipe. Lots of white smoke that didn't go away after a few minutes running time. The new head gasket set should be here in about a week.
Funny it showed no signs of this while on the trip, and it never over heated. At least with all the parts that I needlessly installed, I should have a more reliable bike.
Live and learn....
Thanks, Del
 

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By the way, the local Honda dealer said I could trade up to a 2009 Wing for only $14,000.
Pulease!
:ROFL: :ROFL: only 14,000.00 :ROFL: :ROFL: if i had that kind of mooly i could get a 2013 . than make payments i could afford .:readit: yeah --- i know---dream on sucker :sadguy:
 

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diagnose don't guess. You can tell if the plugs are firing by putting inductive timing light on the individual plug wires. if a plug is missing it will show up by the light not having an even flash. Check for vacuum leaks or fuel starvation. both cause a lean condition which will cause a backfire on deceleration. check the compression hot. early valve failure sometimes begines to show up when the engine is warm. If you just start buying parts the cost to repair a problem will depend on how lucky you are. If you diagnose the problem first the cost will depend on how smart you are.

Steve
 
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