Fast idle...

[mack]

When you

cleaned the carbs, how far down did you strip them? IE did you strip the bank a part and clean the linkages and springs near the idle ajustment screws? if 1&2 balanced easily and 3&4 same. The issue didn't manifest itself until you tried to dial in 2&3 i'd say the likely culpret is the spring and tab location if the cable isn't hanging. Dwayne had the same problem last year at the north rally. He had take the carbs off and work the throttle likages with spray lub to get the butterflys to close properly. That happened on the first day and he drove it all the way up from the south before it happened.

[BA80]

You need to look and see why there is at least one carb being held open.

Did you do any carb work when you had it apart?

[Schming]

JAT, could it be the throttle adjustment up at the handlebars too tight and actually shortening the cable and not letting it return to its stop at the carbs ?

[BA80]

JAT, could it be the throttle adjustment up at the handlebars too tight and actually shortening the cable and not letting it return to its stop at the carbs ?

That is one of the reasons I said to disconnect the throttle cable from the carbs and see if that makes a difference.

However, if I understand what was posted the problem didn't manifest itself until the sync was attempted.

[skids]

You don't have a clamp preventing movement do you?
When you rotate the grip and release does it snap back?
You might need to adjust pilot screws now that the synch has changed idle vacuums are changed but I would make sure there are no air leaks 1st.

[DGXSER]

My money is on something holding the throttle cable.

[BA80]

You don't have a clamp preventing movement do you?

Good point skids. A clamp slightly out of place can do that too.

[Petersg_99]

I hate to suggest it, but you might be best off if you pull the carbs, bench sync them and re-do the sync on the bike.

It sounds like something got really out of whack and it might be easiest if you start over...

[Cuda 69]

before I pulled the carbs back off,I'd do as been suggested on here,and check all the cables,and anything that may affect it's operation.Start with the obvious and work toward the most complex.Imho.

[mack]

No matter

How you slice it, something is causing the #3 carb butterfly to hang up. Cable , throttle linkage, dirt or foreign object.

[motoman]

I'm going to go out on a limb and say that's where your problem is. You can't properly sync carbs above about 800RPM.

+1 on that RPM sync! Larry, presuming those are the later carbs since bike is an 80model(correct?), your initial fuel mix setting should start out at 2 1/2 turns out, not 1 1/2 turns from seated. That would explain the lean high rpm's. Then U have to set fuel mix initially. Can be done one of two ways. Back them out till JUST hits the highest rpm, re-sync. Repeat BOTH till no change. The 'lean drop' method backs srews out a few turns from initial setting, then SLOWLY in till you hear the ever so slightest change/rpm drop, at which time back mixture screw out 1/8th to 1/4 turn. Either way works, and each method will be within an 1/8th turn of each other. Repetition is key. There is no such thing as setting mixture screws and syncin' with one pass over things and callin' it a sync......not happening.

[Tat2demon]

Did you take out the butterflies?

When I rebuilt mine I tore them all the way down. When I re-assembled them one of the butterflies wasn't perfectly in place which led to them all staying just a hair open. It was enough that I couldn't get the idle down below 1600.

If you did, loosen the screws and open/close them a few times quickly to get them lined up properly.

[LoHo]

I will take the carbs off and have a look. I eyeballed them before I put them back on, but I've been walking the line between getting them to spec and leaving them as they were when the bike worked. Where's the damned reset button on these bikes?

I solved the oil leak. It seemed to be from the head gasket, but I think that's impossible. It turned out to be the oil feed bolt at the back of the head, which leaked down to the head mating surface and leaked around the front by the #1 exhaust. Tightening that oil feed bolt solved the leak.

[XS1100_OEM4ME]

Carbs

I will take the carbs off and have a look. I eyeballed them before I put them back on, but I've been walking the line between getting them to spec and leaving them as they were when the bike worked. Where's the damned reset button on these bikes?

I solved the oil leak. It seemed to be from the head gasket, but I think that's impossible. It turned out to be the oil feed bolt at the back of the head, which leaked down to the head mating surface and leaked around the front by the #1 exhaust. Tightening that oil feed bolt solved the leak.

Put the carbs in a window with the sun comming in and adjust the butterflys till no light can get through on any of them, then turn your idle screw till you just see light comming through one and set all to match, as good as a bench sync and proves that all will close completly Must of course sync on the running bike also