mixture adjustment GS1000

[north49]

re: '80 GS 1000 G
.....after looking at my plugs the other day, I noticed #3 was running a bit richer than the others. Is it possible to slightly adjust the mixture ? If so, how's it done ?
thanks, as usual, for all the input.

[tkent02]

Sure you can. Third from the left?

[BassCliff]

Hi,

Yes, be sure you are numbering your cylinders correctly. The cylinder closest to your left leg (as you are sitting on the bike) is #1.

If it's actually the #2 cylinder that's giving you problems, it may involve a different procedure to fix properly.

Feel free to visit my little website (link below) for lots of information.

Thank you for your indulgence,

BassCliff

[KEITH KRAUSE]

re: '80 GS 1000 G
.....after looking at my plugs the other day, I noticed #3 was running a bit richer than the others. Is it possible to slightly adjust the mixture ? If so, how's it done ?
thanks, as usual, for all the input.

Were the plugs at an earlier time running correctly? Or did you just notice and it could have been like that a long time?
If your richer plug read was after minimal throttle positions then you would try adjusting the mixture screw a little leaner (inward). This would lean out the pilot circuit some and that's the circuit you're running on mostly when at smaller throttle openings. The mixture screw for each carb/cylinder should be set by using the highest rpm method. If this is strictly a mixture screw (too-rich) issue then you should hear the rpm's max out when the screw is turned inward just a little, probably no more than 1/2 turn. Just be sure to take note of the screw position so you can put it back the same way if you want. Also, keep in mind that there should be a spring around that screw and that stops it from moving on its own. So if that plug once ran fine then it's not likely the screw is at fault because it shouldn't be able to move on its own (assuming there is a spring).
Float level can change with miles/time and that could give a rich reading too. A worn float needle valve can cause a richer mixture by allowing the bowl level to be too high but not to the point of being obvious yet, such as leaking. A partially clogged air jet. Worn o-rings can cause rich issues. Could also need a vacuum synch.
Be sure that plug is good by the way. Properly gapped? No missing or popping sounds? No cracks/arcing along the plug lead or loose connection anywhere?

[north49]

...to tkent02 and BassCliff.....the rich cylinder is 3rd from the left.