Carb problem or ???

[Guest]

I just disassembled and dipped the carbs on my 82 GS1100. Before I started, cylinders 2 and 4 were the only ones doing any work to speak of. After reassembly, 3 and 4 are doing the most work with 1 and 2 contributing very little. I bench synced the carbs and I have a Carbtune to fine tune but I don't think I'm ready to do that yet. Using a screwdriver I manipulated the lever on #1 carb to open further without disturbing the others and it made no difference in the idle speed. Adjusting the idle mixture screws on 1 and 2 have no affect on idle speed. Compression tests reveal 145-150 on all cylinders. I plan to do a valve check over the winter but looking at what the symptoms show I don't think valves are my most immediate problem. I have fresh spark plugs and they are firing. I am thinking the next step is to remove carbs 1 and 2 and recheck the pilot jet passages on these. Any other ideas? Am I on the right track?

[Crankthat]

Would start by taking a good look at all your boots (carbs to motor/carbs to airbox) Loosen airbox to frame bolts and move carbs around to see if makes any diffrence. (a leak somewhere)

Make sure all your clamps are where they need to be and centered.

Did airbox boots unseal from airbox when reinstall of carbs?

Thread not to long ago from a person who had a warped airbox.

Diaphragm's get misaligned on carb rebuild?

How was the fuel tank?

Particles from tank re clog jets?

Filter housing attached to airbox good with filter installed?

A lot to check.

List some more symptoms and hopefully someone with more experience then me can chime in.

[Crankthat]

http://www.thegsresources.com/_forum/showthread.php?t=199904

Should take you to thread about warped airbox.

[gearhead13]

Do the sync. Bench syncs are just to get them in the ballpark. If you did the carbs properly, you shouldnt have to second guess them. Do you have an inline fuel filter?

[tom203]

If you " manipulated the throttle lever on #1 " and it had no effect, then the idle circuit must be plugged (assuming there's fuel in bowl and you got spark at right time). A bench sync is adequate till you get all the carbs doing about the same work.

[barnbiketom]

carbs are plugged

[Steve]

... I have a Carbtune to fine tune but I don't think I'm ready to do that yet. ... I plan to do a valve check over the winter but looking at what the symptoms show I don't think valves are my most immediate problem.

You are on the right track but your sequence is a bit off.

You don't want to do a vacuum sync with the Carbtune until after you have adjusted your valves, but right now, you have NO IDEA what your clearances are, except for the apparently decent compression numbers.

How long did you dip the carbs? Did you use all new o-rings when you re-assembled? Float height? All passages cleaned and verified? Mixture screw settings?

.

[brownford]

Carbs were each dipped for 24 hours. All jets were removed and I blew air thru each at reassembly. All new O-rings. Floats set per specs. I stuck a piece of copper tubing on the end of my propane torch and directed gas at and around all 4 boots of carbs 1 and 2. No change in idle. Next step is to remove carbs and check pilots for blockage.

[brownford]

you have NO IDEA what your clearances are, except for the apparently decent compression numbers.
.

I know I need to check the valves, but since cylinder 2 was putting out prior to the carb cleaning and now it isn't, it make me think I did something wrong or am overlooking something.

[brownford]

More testing and analysis now leads me to question valves as being a problem here. I know #1 is getting fire because I can see it when I take the plug out and spin the engine. Today I took the vacuum port plug out and let it sniff some propane and it made no difference in the idle. When I do the same to #4 the idle speeds up, so that makes me think that gas is not making it to or not staying in the combustion chamber. Gonna have to order a gasket and pull the valve cover sooner rather than later.

[MisterCinders]

Not sure if this imports into the land of CV carbs, but check the bodies for 1 and 2. On VMs, if you get those transposed, (i.e., 2-1-3-4 instead of 1-2-3-4), then the outside carb on the left will get no fuel. AMHIK

Perhaps in the CV system this could interfere with the inside carb as well.

[brownford]

Not sure if this imports into the land of CV carbs, but check the bodies for 1 and 2. On VMs, if you get those transposed, (i.e., 2-1-3-4 instead of 1-2-3-4), then the outside carb on the left will get no fuel. AMHIK

Perhaps in the CV system this could interfere with the inside carb as well.

Good thought, but that's not it. #2 carb has the vacuum port for the petcock so it's hard to get it in the wrong spot. As I mentioned earlier, #2 cylinder isn't doing much of anything either. It's just easier to experiment with #1. Temp gun shows cyl 2 and 3 running around 250 to 300, with 1 and 2 90 to 120.

[koolaid_kid]

Yeah, you really can't get them mixed up, they won't gang up correctly if you try.