carb problems!

[roadhamr]

the bike starts and runs well enough, it is a 1981 gs1100e. it has an erratic idle at times especially when it is cold. i feel the motor drag when cruising along. like i am suddenly hitting a gust of wind. i have yet to set the valves or sync the carbs this season. would this be the culprit?

[ryonker]

the bike starts and runs well enough, it is a 1981 gs1100e. it has an erratic idle at times especially when it is cold. i feel the motor drag when cruising along. like i am suddenly hitting a gust of wind. i have yet to set the valves or sync the carbs this season. would this be the culprit?

I am assuming you cleaned the carbs already, right?

Sounds like it might be starving for gas at those points. How's your petcock? Is it the stock vacuum one? Is the bike stock...ie. exhaust and air box?

Just thinking out loud with you.

Rick

[roadhamr]

the bike is stock the carbs have been cleaned and it is the stock petcock and exhaust ect. i have been suspect of the petcock for awhile. i should proably put a kit into it and maybe some new hoses both fule line and vacuum. but i think the carbs need to be sync'd as well.

[BassCliff]

Hi Mr. roadhamr,

I'll think out loud a little too.

Are your carb vent tubes routed properly and protected against turbulence? Do you have a tight air intake system (good/tight clamps, intake boots, o-rings, airbox boots, airbox sealed, etc)? Are you sure the carbs are clean? Sure, check the petcock too. Is there any difference when running on PRIME? Could it be just some bad gas? Is there any rust/debris in the tank? Is the petcock's filter screen clean? Are you using an inline fuel filter?

What makes you think it's fuel-related rather than spark-related?

OK, that's it. I'm tired of thinking now.


Thank you for your indulgence,

BassCliff

[hampshirehog]

You should always make sure your valve clearances are ok before playing with your carbs. Your description of the symptoms when on the move sounds a bit harsh for it just to be a carb synch (but you know you should do one anyway!)

Could be a dodgy fuel tap or the vacuum line could be twisted / perished.

[roadhamr]

if i switch the tap to prime and surging and power drop off stops is this a clear indicator it is the fuel tap or something surrounding the fuel tap? i am planning to get a rebuild kit and new fuel and vacuum lines for it so as to be sure. the vacuum line is a bit on the short side and may be kinking or not sealing well around the nipples. the fuel line seems fine but i will replace it and the inline fuel filter as well to be sure. there was some debris in the tank when i cleaned the carbs but i was careful to clean the tank very thoroughly and i will empty the bowls on the carbs and see what i get i may have to line the tank after all and reclean the carbs. does this seem like a reasonable path to go down?

[rustybronco]

if i switch the tap to prime and surging and power drop off stops is this a clear indicator it is the fuel tap or something surrounding the fuel tap?

BEATS ME!!! j/k...
yes it sounds like there is an issue with the petcock screen being plugged.
you can try removing it and cleaning the screen first. if that doesn't help, then I would replace the petcock rather than trying to rebuild it.

[roadhamr]

I have found a replacement petcock at the local suzuki dealer and i will be doing the swap shortly will keep everyone posted as to the results
thanks

[roadhamr]

the idle has sorted itself out, it revs freely and the problem seems to have been sorted by replacing the petcock and the fuel and vacuum lines and putting in a new filter. i have yet to give the bike a shakedown as we are having a pretty good rainstorm right now. i will put up the results of the ride as well. thanks for the advice.

[roadhamr]

the swapping of the petcock for a new one seems to have eliminated most of the problems. there is still a slight hesitation which i would say could be valves and carb sync. i also think i am going to have to line the gas tank as i found some particles of rust in the old petcock around the base of the screen. i had a good run out to wiarton and back this weekend and it was fairly trouble free! thanks again.