3.5 Cylinder gsl1100-help!

[Anonymous]

I suddenly have a very sour sounding 1984 GS1100L. Rode it home from work last night....knew something was wrong right away. Lagging roll-on response, idling slow. This a.m. I fired it up, and one of the exhaust headers was noticeably cooler to the touch than the other three, at least for the first several minutes with the choke on. Riding it again revealed much the same behavior as last night, only more so: if I roll on and keep the revs up the bike will suddenly "kick in" like an intermittant cylinder is coming back to life. The exhaust sound is "sour" with lots of popping when I roll off the throttle, and even when just normally revving down with the throttle closed, say, while approaching a stop. The bike died while sitting at idle while I removed my helmet. None of this behavior is normal, and its obvious to me the bike's sound is not right, not to mention its over the road behavior. It has ~10k original miles, recently had the carbs gone thru, and yes, original electrics. I've been running a one step hotter plug, as they have looked a touch on the dark side.
Any thoughts would be appreciated!
Scott

[Alan Schlosser]

I don't have any advice but I'm dying to know.... an 84 1100L? I only thought they made the 1100L in 82 and 83. What's up?
Al

[Anonymous]

3.5 cylinder gsl1100

Sorry Al, it was either a senior moment, a brain fart , or crappy editing. It's an '83 gs1100l :roll:
Scott

[redliner1973]

Sounds like a pilot jet getting clogged up on that cylinder. The popping tells me it is lean. :?

[Anonymous]

The intermittent nature sounds to me like an ignition problem. Check your sparkplug boots. Unscrew the ignition lead and check the resistance of the boot itself. It should be 5,000 ohms across the thing. When they are old they start to open-circuit intermittently, then they go permanent.

Swapping the boots between two cylinders is a good way to check. The problem will then transfer to the other pot.

If you need to replace one, do them all. Boots cost a few bucks and if one is going out the others will want to follow soon.

Kim

[SqDancerLynn1]

Each Ign coil fires two cyl so more than likly ok? Check the plug and plug cap. With only one bad tho I would check the carb. Check for pluged jets. Another possibility is to drain and refill the carb a few time to see if it can be flushed out

[earlfor]

Re: 3.5 Cylinder gsl1100-help!

Since the problem is only one cylinder and only at low rpm, I suspect that a bit of dirt has found its way into the pilot jet on the
offending carb. When you first start it up, if one pipe remains cold at idle rpm, its a pretty safe bet the idle jet is clogged.

Earl

[quote="slstamper"]I suddenly have a very sour sounding 1984 GS1100L. Rode it home from work last night....knew something was wrong right away.

[Anonymous]

3.5 cylinder gsl1100

Earlfor & all
What makes this frustrating is that the carbs were gone thru less than 6 months ago; the tank was cleaned out, de-corroded, and lined, and, inline fuel filters were installed at that time. Seems like a fuel/carb/dirt issue in theory should be one of the last things I should be dealing with now........yes, I know, life's not always fair!
Is it possible that I have 2 coils that are detiorating (bike gets relatively poor milage: 38 mpg with a laid back riding style), plugs look rich (possibly indicative of poor spark) & the problem is intermittant in intensity? I rode the bike today in much warmer temps and the exhaust popping came and went during the ride; at times the bike felt fine, other times it felt like it was running on 3.5 as described before. Grrr.
Scott

[focus frenzy]

sounds like a fouled plug, have you changed the plug for the cylender that is cold when started?
the center electrode of the plugs should be a light tan to light gray color, black is bad, this indicates fouling wich will ground out the plug.
there are two types of fouling, gas and oil.

when I purchased my bike it sucked oil like it was going out of style, to the tune of a quart every 300 miles.
it would foul the outer two plugs (1&4) at first it would drop cylenders at low revs and getting the rpms up would blow them out and it would run good before finnaly completly fouling the plugs.

[earlfor]

Re: 3.5 cylinder gsl1100

Scott, I think its improbable that both coils would start to degrade at the same time. If even one coil was going bad, you would have two cylinders that had the same problem. With an intermittant wiring connection to just one of your coils, you would still have two problem cylinders. Its possible the problem is a bad spark plug boot on one cylinder. You could try swapping boots and see if that makes any difference. A new one is only about $3 if you find that to be the problem. Its also possible you just have a spark plug gone bad or fouled/grounded out. Try swapping plugs around to see what hepppens. It only takes a salt grain size piece of dirt to clog a pilot as the blasted things are tiny. :-) As for fuel milage, I can vary my fuel milage by 8 miles per gallon with adjustments to the pilot and airscrew needles. ( I made adjustments and recorded milage and fuel consumption exactly on a tankful at a time) It also reflects very noticably on what color the plugs burn. I believe (my estimate) average milage for an 1100/1150 is around 43/45 mpg. You should be able to achieve that with minor adjustment. I have tried taking the float bowls off and adjusting/cleaning a pilot with the carbs on the engine and its just too much of a hassle as far as I am concerned. Its much easier to pull the four carb stack off and turn them over on a bench.

When you start it up and its at idle of 1000 rpm or so, does the one pipe stay cold? If so, when holding your hand on the pipe and increasing throttle in stages, what rpm does the pipe start to warm up? Also, when you first start it up and its idling with a cold pipe, you might let it fun for 30 seconds and then shut it down while the pipe is still cold and pull the plug on that cylinder. If the plug is wet, it is not a fuel problem. If its dry, it is.

Earl



[quote="slstamper"]Earlfor & all
Seems like a fuel/carb/dirt issue in theory should be one of the last things I should be dealing with now........yes, I know, life's not always fair!
Is it possible that I have 2