poor idle, GS1100

[Anonymous]

i have a 1983 GS1100G with under 23k miles. it spent about two years in my dad's shed before i got my motorcycle license and rescued it about 8 months ago. after an oil change, new plugs and my dad cleaning the carbs (i'm not sure exactly what he did, but he did not disassemble them at all), it runs great once warmed up except for at idle.

i'm still fairly new to motorcycles, but have been working on cars since before i could drive, so i'd like to think i pretty much know what's going on. i believe it has an aftermarket ignition coil, each carb has an individual air filter, and it has a slightly beat-up vance & hines "street megaphone" exhaust setup. as far as i know, everything else is stock.

i have two main questions. the first: is it normal for the idle to vary greatly between a cold and warm engine? if i set the idle to just barely above 1k RPM when i start it, after fully warmed up the idle will reach well over 3k unless i adjust it again. also, if i hold the clutch or put it in neutral when stopping, the idle will usually hover around 3500RPM for a good 5-10 seconds before dropping back down to normal.

second: at idle, and more noticeably once the engine is warmed up, there is a slight popping/puffing sound, and a small puff of smoke comes out of an air filter. each time this happens, the engine speed drops momentarily (meaning there's a misfire of some sort).

i'm hoping to completely disassemble/clean the carbs once the weather warms up a little, but i don't know where to find gasket/rebuild kits. i'm also not sure if rebuilding the carbs would fix these issues. any input on how or what to do to improve idle will be appreciated. and thanks for the patience with the long post...

[shaftzuki]

Your going to have to get back into those carbs and make sure the idle circuits are clean and functioning - it will not idle correctly until this is done. You can reference our carb clean up series located at:

http://www.thegsresources.com/gs_carbrebuild.htm

just take your time, follow the instructions - you can do it!! 8)

[Anonymous]

thanks for the quick reply. is it likely that all problems (including the puffs of smoke coming from the filters) could all be fixed by cleaning/rebuilding the carbs, then?

also, are there any online sources to find carb gasket/rebuild kits for this? i looked for hours a while back without any luck.

[earlfor]

You have obstructed or partially obstructed passageways in the carbs. Your float heights may not be quite right either and considering age, I would be willing to bet your float needle valve "O" rings are not sealing which will cause random fuel levels and flow. All you need is a gallon of Berrymans solution to soak the carbs in and then blow them out with a compressor.
You can order float bowl gaskets alone for a few dollars. I would just order bowl gaskets from through my local dealer as I'm guessing they are probably only about a buck each if that. Just clean your jets when you have them removed. There is no need to replace them and many aftermarket kits have jets of questionable accuracy. The "O" rings you can buy from robert Barr at http://www.cycleorings.com/
The "O" ring kit contains all the "O" rings you will need for four carbs and is $12. You can order online through his site with paypal or if you dont have a paypal account, you can use a credit card.

Earl

[Anonymous]

thanks for the help. it doesn't look like i'm going to get that trip to florida i wanted for spring break, so chances are pretty good that i will have everything cleaned up and put back together over that week.

[Jethro]

In response to your 1st question, it sounds like you might have a lean condition in pilot circuit. The idle will most likely change a little after it first warms up, but not by 2500 rpm. The slow to return to idle problem could be an air leak. But you won't be able to evaluate this stuff until the carbs are gone through. When you have them off the bike, make sure to check the o-rings on the back of the intake manifolds, I think the big G's have them. Also make sure the intake manifold boots aren't cracked. When they are off, squeeze them a little and look for cracks and splits. These old bikes suck a lot of air, even a small crack can make the bike run poorly.