1983 GS1100 carb/ignition bugaboo

[oregonjake]

Okay, my new 1983 GS1100E and I just got back from her first 75 mile shakedown ride. Here is what I noticed, and am not sure if it is ignition/electrical or fuel/carb so will post this same question in the electrical forum. If I roll the throttle on smoothly, she accelerates like a liter bike should, up to about 5Krpm, then it feels like either one or two cylinders quit sparking OR one or more carbs ran out of fuel. If I smack the throttle open she immediately shows the same symptoms IF I am between 4 and 5Krpm, at lower rpm she takes right off. I am trying to use my vast but aged memory to think where I should start, my first thought is ignition. I don't want to pull the carbs just yet, hopefully it will be just a minor hiccup and not a massive undertaking. The bike has a tach that is wired to the ignition, and the needle starts fluctuating between 3500 and 4000rpm, never going above 5K. Could the tach be wired wrong as to cause the ignition to malfunction, or should I look at another component? Could the float levels be too low as to cause fuel starvation when I crack the throttle? Thanks in advance for the advice.

[phydeauxmutt]

Just how many sections do you have this posted in? I saw at least THREE.

[posplayr]

I would suggest hot wiring your coils to rule out the ignition. On the other hand I don't know why you think you might have carb problems . Did you put on pods or do anything that would require rejet?. Make sure the carbs are clean and your petcock is flowing.

[oregonjake]

Sorry, I put it in electrical, carb and the general GS owner forum. If I posted too much I apologize, you have my permission to excoriate me in the appropriate manner.

[oregonjake]

The stock airbox is still on, as are the stock pipes. I felt maybe carbs as the symptom to me seems like maybe starved carb? I was thinking float level was low and the carb got sucked dry when I whacked the throttle. I am sorry, my aged brain has forgotten how to hot wire the coils. Thanks.

[posplayr]

Hot wire=alligator clip from batt+ to either coil +

[storm 64]

I would gess your problem is in fuel/carburetor aria. Since you have a later model GS, the electronic ignition system rarely fails. But as Posplayr said make sure your getting proper voltage to your coils. Good luck.

[londonboards]

If this is happening as soon as you take off (after the engine has warmed up) then it's unlikely to be fuel starvation.

Floats don't miraculously changed heights, even when you rebuild the carbs. It takes a significant effort to bend the tang. As long as the float is in the vicinity of the prescribed level, the bike should perform pretty well. If they are too low (not retaining enough fuel in the bowls) you would get starvation after some moments at full throttle. If the floats were set too high you might get some flooding and choking at slower speeds.

If you are not able to get her above 5K rpm then I would guess main jets are not supplying fuel. I had this once, see here:

I had put the throttle slides together incorrectly. The needles were incorrectly assembled and the main jet was not opening. You didn't do what I did, did you:



Correct assembly of course is the left one. The way I had them was forcing the needle into the main jet shutting it off. You can also, either put extra washers just above the spring or change the position of the c clip (if you have that type of needle) to adjust when the main jet starts to open. Although, like float tangs, if the carbs/bike was working before then nothing should have changed only that you may have reassembled them incorrectly.

[oregonjake]

Thanks, I am going to go through the electrical on Thursday, I hope the gods of voltage and amps look kindly on me. Will post results.

[oregonjake]

Thank you for all the info, it helps tremendously. The needle position is unknown as I did not do the carb work. The kid I bought it from told me he had cleaned and adjusted the carbs, and yes I am old enough to take what he said with a large grain of salt. I am trying to avoid pulling the carbs but it looks like I am going to have to anyway, as working on them is much easier on the bench and I might as well check the jet size and put them back to stock configuration.

Do you know stock jet sizes for my 83 1100? I know I can find them online, just thought you would know off the top of your head.

[posplayr]

Thank you for all the info, it helps tremendously. The needle position is unknown as I did not do the carb work. The kid I bought it from told me he had cleaned and adjusted the carbs, and yes I am old enough to take what he said with a large grain of salt. I am trying to avoid pulling the carbs but it looks like I am going to have to anyway, as working on them is much easier on the bench and I might as well check the jet size and put them back to stock configuration.

Do you know stock jet sizes for my 83 1100? I know I can find them online, just thought you would know off the top of your head.

I do know but you should practice using the factory manual.

[JJ]

Alternatively, there's a sticky at the top of this forum section that gives the info.

[oregonjake]

Okay, lesson learned. I'll look it up, and buy a factory service manual.

[posplayr]

Okay, lesson learned. I'll look it up, and buy a factory service manual.

Or just try this...............

http://zeus.mtsac.edu/~cliff/storage/gs/80-83_GS1100T-LT-EX-1000SZ-EZ-SD-ED-ESD.pdf