Extremely rich mixture, crappy fuel mileage, newbie needs help

[flyanimator]

I recently bought a 1980 GS1100L. It ran when I purchased it albeit, not perfectly (it popped a bit from the exhaust, i did not hear it pop from the carbs). I took it in to a local motorcycle shop to have the carbs cleaned and synched. I goit it back from the shop and the engine runs smoothly and the popping stopped almost completely ( it still pops from time to time, not very often though). The problem that I have now is that I have run a little under 60 miles and my tank is almost empty. Also, when I stand behind the motorcycle while it is running, my eyes immediately start to burn with the unburnt fuel ( my indication that it's running extremely rich). I know that these engines ran somewhat lean from the factory and I have read that they should get about 50-60 miles per gallon (i'm getting somewhere around 12 mpg or so). I know that being an old bike, it will not have the same performance and fuel mileaga as when they were new, but I know it should get way better than what I have at the moment. My question is, what can I do about this, and if I do make adjustments top lean out the mixture, will I have to re-synch the carbs? I will be aking this up with the shop that worked on it. I would just like an honest, unbiased opinion from all the great bikers on this site to make sure they are not feeding me any B.S. Also any other things that you can sugest I check would be greatly appreciated as well as any advice. Thanks.
-Rudy

[Nessism]

Number one rule: Learn to work on your own bike and stay the HE!L away from hack motorcycle shops.

First step is to rebuild the carbs yourself and check all the jets to see if they match the factory spec. You didn't mention if you have any mods? Hopefully the bike is stock so you can compare the jets to the sticky on the top of this forum.

Good luck.

[chef1366]

Is this the rare chain drive L model?

[flyanimator]

Nessism, the bike has no modifications that I am aware of, aside from the handlebars that I changed last week.
Chef, yes. This is the chain drive model that was only produced for one year, like yours.

Thanks for your help guys.
-Rudy

[chef1366]

Actually these bikes got around 35-40MPG stock. If your getting 12 than something is wrong. I would check that you have 12 volts at the coils and what jets you have intalled in the carbs.
Get a compression tester and do the valve clearance.

[flyanimator]

thanks chef. I will run a comp. check tomorrow as well as check the coils and I'll yank the carbs out this friday to check out the jets. What kind of comp reading should i be looking for? Somewhere in the neighboorhood of 160 I imagine. Anything else i should look out for?

[chef1366]

100 at the lowest. I don't think you'll see 160. These are not high compression motors. Remember to check the motor warmed up with the throttle held wide open.
If the compression numbers are low drop a little oil in the cylinder. If the number rises your rings need attention if not your valves either need adjusted, valves are worn or seats are pitted.
Stock jetting on this bike is
Main jet 107.5
Pilot jet 45
Pilot air jet 160
Are you running an airbox and stock pipes?

[flyanimator]

The bike is all stock (save for the handlebars). It's running the airbox and original pipes. Is there anyway that i could be running rich enough to burn my eyes with the stock jets? If so, how can I correct this? Can you point me in the direction of a good source of info on how to check and adjust valve clearances. I'm pretty handy, having worked on all kinds of cars old and new. I've just never worked on a bike before. I would assume the basic theorie's are the same. Please correct me if I'm wrong though.

[SqDancerLynn1]

If it's all stock the float level could be set too high, make sure you have the rubber plug for the main jet well

[flyanimator]

Thanks for the tip Sq. How can I adjust that? Is there a thread on the procedure or a write up somewhere? I'm new to these bikes and would like to have a reference before i go about changing anything.
Thanks.
I honestly think that the shop i took it to adjusted something wrong on it cause before I had it "fixed" it did not run that rich. I don't know what kind of mileage it got before, but the exhaust gasses literally burn my eyes as soon as i stand behind the bike from how rich it is. I think it was running lean before, because the exhaust started turning blue like when chrome is overheated.

[C.V.]

Could the choke be stuck? It was worked on by "professionals"

[Steve]

It was worked on by "professionals"

How true, how true. I learned long time ago about the meaning of "professional".

It has nothing to do with how good they are, only that they got paid to do it.

.

[flyanimator]

the choke is operational. I can pull the knob and push it back down and the plunger moves with it at least on the outside of the carbs where i can see it.I'll be checking compression and voltage to the coils today. I'll let you all know how it goes.

[flyanimator]

Their shop seemed legit and all, but I guess appearances are not really what they seem. I would have liked to have done this myself, but I don't have the synch tool to do this so IO decided it was better to have it done by someone who "knows" how to do it. I guess I was wrong there, too.

[C.V.]

Their shop seemed legit and all, but I guess appearances are not really what they seem. I would have liked to have done this myself, but I don't have the synch tool to do this so IO decided it was better to have it done by someone who "knows" how to do it. I guess I was wrong there, too.

Unfortunately, "legit" doesn't mean much! I use the local shop just for tire changes, and they've screwed that up 3 times (pinched tube, loose valve stem, no balance..I'll be doing myself next time...) FWIW, i got my bike running pretty good w/ just a bench sync on the carbs, i can wait for the fine tuning (who's got a manometer for me...). Most of the guys at the dealers are little more than oil changers, and are completely at a loss w/ our old bikes. Learning to do it yourself is fun, less expensive, and you'll ALWAYS have a professional to work on your bike!

Good Luck