carbs clean - can't start...

[Anonymous]

Sigh.

I just cleaned the carbs on the 1980 GS1100L that I was given, and reinstalled them. The bike still barely starts. With the filter box off, and some starting fluid, it'll barely start, idle for 10-20 seconds, and die. Won't start with the filter box on.
This isn't much different than before the cleaning, though the idle is a little smoother.

I'm thinking it could be a vacuum leak, but I've tried the WD40 test, with no luck. I can't even synch them if the bike won't start. Plugs are new, but slightly fouled due to trying to start it before the cleaning.

What could it be? (and I've read the carb problem threads in the first six pages of the forum too).

[Anonymous]

What could it be?

I'm not an expert, but I have had my share of carb issues...You can synch your carbs by eye as a starting point. Take the carbs off the engine and look at the butterflies from the engine side. Visually line up the butterflies using the adjustment screws. Last time I did this I used the idle jet holes in the body as a reference point to get them all close. That will at least get you in the ballpark and will definitely be close enough to get it started.

As for your hard starting, you need 4 things to get it running - air, fuel, spark, and compression. Check them all and be methodical and you will find the problem.

1) Air - should be no problem, especially if you are test starting it with the airbox off.
2) Fuel - This is where I would start, as this sounds like a fuel supply problem. After cranking for a while, do your plugs come out wet or dry? Are your carb bowls filling with fuel? Is your petcock operating properly? Fuel lines and/or filters plugged? Check the entire fuel system and I bet you find the problem.
3) Spark - sometimes a weak coil will fire using starter fluid, but will not have enough power to fire the normal fuel/air mixture. Since your bike will idle for a bit on gas after it starts on ether, I don't think your ignition system is the culprit. CLean your plugs and make sure they are gapped properly. Check the continuity/resistance values on your plug leads and the coils just to be sure they are OK.
4) Compression - this shouldn't be a question if your bike fires. It may be too low to make best power, but it should start and run even with incredibly poor compression.

HTH,
Mark

[Anonymous]

Plugs are a little wet, but not fouled. I changed the plugs out when I picked up the bike, which was before I had the carbs done. At that time, the starting was about the same as it is now. Runs for a few seconds, but stalls.

The carb bowls are filling with fuel. I drained them to check that out.

The ignition seems strong as far as trying to turn the engine over - until I wear out the battery of course.

I replaced the throttle cable as well - could it be a matter of adjustment on that? I'm going to replace the choke cable - the aftermarket one I bought from Dennis Kirk didn't fit so I'm waiting for one in the mail.

Could be bad fuel lines I suppose, but with the carbs filling up, that doesn't seem to be it. I have a auxillary fuel cell for my Concours that I use for distance rides. I'm considering hooking that up in place of the stock tank to see if perhaps the petcock on the tank is bad.

[Anonymous]

I'm considering hooking that up in place of the stock tank to see if perhaps the petcock on the tank is bad.

If there is a "prime" position on your petcock, that will let it flow gas no matter the vacuum it is getting. That should solve any flow issues from the petcock. But changing out to a different tank will definitely eliminate any questions there.

Can you run it longer by playing with the throttle? Is the idle set too low (hard to tell, I know)? It still sounds like a fuel delivery problem to me. If it will fire and idle a bit, then everything else is working at least OK and the one thing left is fuel. This almost sounds like a plugged vent line, but the thing should run at least several minutes before stopping if your tank is not venting properly.

After that, I am stumped. The only thing I can add is to be very methodical and go one component at a time to find the trouble. :?


Mark

[Dave_A]

Your bike should have trouble running with the airbox off... That's normal...

1) Try starting with the choke pulled out by hand... Reach down there & grab where the cable connects, and pull up...

2) To test the throttle thing, crank the motor and open the throttle slowly as you crank. Your throttle adjuster may just be set too low...

3) Have you tried spraying starter fluid into the airbox with the airbox attached?

[Anonymous]

Your bike should have trouble running with the airbox off... That's normal...

Dave, why is that normal? I have never had a bike fail to run at least OK with the box off. It will be lean compared to running with the airbox sealed up, but it should at least start and idle OK.

I'm not trying to be argumentative, just wondering that's all.


Mark

[Jethro]

Yeah, my bike has absolutely no difference with or without the airbox.