if everything stock, whys it run lean?

[beachbum3478]

i have a stock 82 gs1100gl. when i got the bike the carbs were all out of wack, but had the right jet sizes. iv gradually fixed all the problems and had it running it good. sealing the airbox was a biggie. main was 115, pilot 40, and pilot air 170. i had the idle mixture screws dialed in pretty well. and the bowls were set at 21.5mm. i checked the plugs and they are all brilliant white. any ideas why? i know the float bowl is a tad low, so i just took the carbs out and raised the bowls to all 22.5mm and upped the pilot jets to 45. now it feels soggy from 1k to 5k and not as pepppy as it was before. and when i come to a stop the idle will drop to 1500rpm,pause, then go down to 1050rpm. whats this sound like to you guys? should i go back down to 40 pilots and leave the floats at 22.5mm. maybe the pilot circuit is too rich with the 45 jet and higher float bowl combo?

also, after upping pilot to 45 and float bowl to 22.5mm, adjusting the idle mixture screws is hopeless, there barely any idle change at all unless i fully close them, but from about 3/4 turn out; the rpm doesnt go up or smooth out. thanks.

[chuckycheese]

Stock

If everything is stock, I don't think deviating from specified jet sizes is the way to figure it out or fix it, either one. I think, with the right size jets, you should adjust your mixture screws until the plugs look just right...start at about 2 1/2 turns out and, if your plugs are really lean and it's popping or backfiring, open them up one at a time, a little bit at a time.

Listening to the RPM's is NOT an exact science and I'd be more concerned with how the plugs look and, most of all, how the bike runs. Also, many people are convinced these bikes run better when they run slightly lean. (Also, don't mess with your float height; it's just fine.)

[beachbum3478]

yea im with you on that one. it doesnt make sense. well i just went out redid the mixture screws. i had most at 2 turns out with the 45 pilot jet. i back them down to 1 turn out and it feels alot more reposonsive but now what i think it should be. i was running mostly around 3k to 4k and i tried to "chop" the bike as soon as i could, it idles for 10 seconds. i took two plugs and both had one side that was white and other side was black.

i guess with the bigger pilot and less turns out on idle mixture then normal it kind of evened itself out right?

[Rock]

Check the intake boots for cracks. They can look good when mounted and still be bad. I took mine off that I thought were good and flexed them when they were off the bike and found out they were in very bad condition. They were still soft but just cracked badly and not noticeable until I flexed them. I'm surprised it ran. They were the originals.

[Redman]

BB,

I pondered the same question for about a year and half with the GS1100GK that I got. Redid the intake o-rings, checked this and checked that. Like you said, if everthing is stock and in good condition, why is it so lean, plugs so white and engine so hot? SOme poeple said "82s are all too lean", other people said check this and check that. Pondered and agonized over it. Then after a year and a half, I upped the mains 2 sizes from the stock 115 to 120. Ahhh, much better now.

.

[chef1366]

Try a 42.5 pilot jet. That's too much of a jump to 45.

[twr1776]

I second the 42.5 pilot and if you are still lean with it you could shim the needles. If you are rich on the pilot jet you will get the searching on idle you had mentioned

[Steve]

...the bowls were set at 21.5mm. ... i know the float bowl is a tad low, so i just took the carbs out and raised the bowls to all 22.5mm ...

Just remember that when setting the float height, you are working upside down. By raising the number, you are increasing the amount that the float will be lower than the gasket surface. Increasing the number of your float setting will actually lean out the mixture.

.

[beachbum3478]

i put the 40's back in and readjusted the mixture screws, most are around 3 turns out. its basically back to normal, i checked the plugs after using 1/8-1/4 throttle, and each plug has a half white/half black sooty electrode base. whats that mean?

[greg78gs750]

im no expert, by any means, but i have heard over and over that "these bikes are dangerously lean in their stock configuration". so....

[82Shafty]

i put the 40's back in and readjusted the mixture screws, most are around 3 turns out. its basically back to normal, i checked the plugs after using 1/8-1/4 throttle, and each plug has a half white/half black sooty electrode base. whats that mean?

Means your fine, go ride the heck out of it.

http://www.ngksparkplugs.com/techinfo/spark_plugs/faq/faqread2.asp

Look at plug #1 It's all you brother, now quit being a hypercondriac and go and enjoy the ride before I send my high rpm breaking up condition your way.

[beachbum3478]

its more of the heat that is generated from the leaness that is gonna bug me, the header are a goldish color out of the engine, dont know if that is normal or bad. but the summer isnt here yet and its gonna be really hot out and i dont want to hurt anything that way. maybe ill try the 42.5's this summer to richen it up a tad.

[Nessism]

If the bike is stock and running well, I wouldn't worry what the plugs look like until they accumulate some mileage - 500 miles or so. If they are still bone white at that point, you might want to dig deeper.

Not sure if it's just the fuel in my area but 3 turns out is about right for most CV's I've seen. Some bikes will still feel a little flat off the bottom so raising the needles a smig can really help.

Needle height is controled by the thickness of the spacer on TOP of the clip - you need to remove the plastic washer and replace it with a small stack of washers. Removing washers raises the needle. Start off with a stack 1/2 as tall as the plastic spacer you removed. This mod made a world of difference on my old 550T, going to do the 850 this weekend.

Good luck.

[82Shafty]

its more of the heat that is generated from the leaness that is gonna bug me, the header are a goldish color out of the engine, dont know if that is normal or bad. but the summer isnt here yet and its gonna be really hot out and i dont want to hurt anything that way. maybe ill try the 42.5's this summer to richen it up a tad.

Have you used an infrared thermometer to confirm your theory?

I have seen many guys make themselves sick over what they perceived to be hot, when in fact, they were well within normal air-cooled operating temps.

[beachbum3478]

yea my infrared thermometer topped out around 220-225, but its never that accurate at that high of temps. its usually under what it really is.

as for changing the needle heights, how do i go about do that. on my bike it is a little flat off from the start. so wouldnt raising the needles add more fuel and make it more soggy on the bottom? do i just take the snap ring out down the slide and the needle will fall out and the rest will be straight forward? any threads or websites further explaining this procedure, as iv never seen this subject covered to much. thanks.