Have had the first of my two GL650 Silver Wings for a few years now. It has always had a hard start problem particularly when cold or having been sitting for a while.
Posted up this problem under another thread a long way back and the general consensus was that it was a fuel starvation problem where the fuel evaporates from the carb bowls after sitting for a while. Old thread is here: Strange Startup-Ignition Problem
Things have gotten worse recently. Two days ago I tried starting the bike. I nearly wore the battery charge down to nothing (fully charged Yuasa AGM battery that's always on a Battery Tender) before the bike would finally start. It started and ran but only one one cylinder. Normally after a minute or so the second cylinder fires up and runs.
Not this time. Bike ran for several minutes but ONLY on the left cylinder. The right cylinder never ran! I could hold the exhaust pipes right outside the head with my hand and it was barely warm to the touch. Only other symptom was that I'd get a rare backfire out of the right exhaust pipe maybe once every 30 to 40 seconds.
I dug into it today, and here's what I found:
1. Both carb bowls were still full after the start up attempt two days ago. (Verified by using clear plastic tubing connected to the bowl drains and opening the drain screws. Fuel levels were the same, about 1/4" or so below the bowl gasket.)
2. Pulled the spark plugs and inspected:
Left plug - a bit carbon fouled, but not bad.
Right plug- fuel soaked!
3. Inspected spark plug boots: Plug boot inside terminals are clean and like new.
4. Tested for spark at plugs. Inserted plugs back into caps and used a jumper to ground the spark plug body. Results:
Left plug: Bright spark between the top of the center electrode and ground electrode.
Right plug: Bright spark between the SIDE of the center electrode and the base of the ground electrode near threaded body! NO spark between top of the center electrode and ground electrode where it should be! See picture below...
Yes, I actually got a picture of that!
So, "what the hell" I thought. I've never seen that before.
QUESTIONS:
1. Why no spark between the top of the center electrode and the ground electrode where it should be? Is there a cold weld where the ground electrode is welded to the spark plug threaded body?
NOTES: Resistance between the spark plug body at the threads and the ground electrode seems to vary between 0.1 and 0.6 Ohms. The insulator around the center electrode is NOT cracked. I inspected it with a magnifying glass under bright light.
2. Is this weird "side park only" condition likely the cause of the right cylinder not firing at all? The spark is just as bright as the left plug, so there IS a spark, but it's definitely in the wrong place. Shouldn't it ignite the fuel/air mixture anyway?
What do you think?
Posted up this problem under another thread a long way back and the general consensus was that it was a fuel starvation problem where the fuel evaporates from the carb bowls after sitting for a while. Old thread is here: Strange Startup-Ignition Problem
Things have gotten worse recently. Two days ago I tried starting the bike. I nearly wore the battery charge down to nothing (fully charged Yuasa AGM battery that's always on a Battery Tender) before the bike would finally start. It started and ran but only one one cylinder. Normally after a minute or so the second cylinder fires up and runs.
Not this time. Bike ran for several minutes but ONLY on the left cylinder. The right cylinder never ran! I could hold the exhaust pipes right outside the head with my hand and it was barely warm to the touch. Only other symptom was that I'd get a rare backfire out of the right exhaust pipe maybe once every 30 to 40 seconds.
I dug into it today, and here's what I found:
1. Both carb bowls were still full after the start up attempt two days ago. (Verified by using clear plastic tubing connected to the bowl drains and opening the drain screws. Fuel levels were the same, about 1/4" or so below the bowl gasket.)
2. Pulled the spark plugs and inspected:
Left plug - a bit carbon fouled, but not bad.
Right plug- fuel soaked!
3. Inspected spark plug boots: Plug boot inside terminals are clean and like new.
4. Tested for spark at plugs. Inserted plugs back into caps and used a jumper to ground the spark plug body. Results:
Left plug: Bright spark between the top of the center electrode and ground electrode.
Right plug: Bright spark between the SIDE of the center electrode and the base of the ground electrode near threaded body! NO spark between top of the center electrode and ground electrode where it should be! See picture below...
Yes, I actually got a picture of that!
So, "what the hell" I thought. I've never seen that before.
QUESTIONS:
1. Why no spark between the top of the center electrode and the ground electrode where it should be? Is there a cold weld where the ground electrode is welded to the spark plug threaded body?
NOTES: Resistance between the spark plug body at the threads and the ground electrode seems to vary between 0.1 and 0.6 Ohms. The insulator around the center electrode is NOT cracked. I inspected it with a magnifying glass under bright light.
2. Is this weird "side park only" condition likely the cause of the right cylinder not firing at all? The spark is just as bright as the left plug, so there IS a spark, but it's definitely in the wrong place. Shouldn't it ignite the fuel/air mixture anyway?
What do you think?