1981 GL1100 Carb Sync Issue

[dshearer]

Rebuilt carbs on my 1981 GL1100 carb #3 is pulling high vacuum 18, other carbs are pulling 7. I know carb #3 is my anchor carb so can't move forward till I get it figured out.

Any help would be great,

Thanks David

 

[slabghost]

Welcome to the madness. How long has the bike been sitting? Have you checked all the connections for leaks? Both ends of intake horns especially. Did you remove mixture screws? Or adjust them?

 

[brianinpa]

Sounds like a leak... As Slab already mentioned check everything... ESPECIALLY the intake horns!

 

[dshearer]

I have had the bike for 4 year, it was high idling all the time after I purchased it so sync the carbs all has been same what good. Hauled the bike to Sturgis last year as the other guys road put 900 miles on it, but the last day started running rough. So this winter started to rebuild the carbs with a kit from Randakk's took them completely apart clean and put them back together and installed bike started and sound petty good. Put the ide screw back as close as I could.

Thanks look at my post. David

 

[dshearer]

I'm on a mission to get it up into top shape and ride it to Sturgis from Missouri this year!

 

[slabghost]

Synchronizing the carbs is getting the butterfly openings even with all the carbs. This brings the slides into play also. Assuming all the slides are free and the springs are even. My guess is you need to bench synchronize.

 

[dan filipi]

Since its manifold vacuum you're reading, higher vacuum in one means the throttle plate is closed more on that carb than the others. Provided there are no leaks.
Since #3 is reference and not adjustable, I'd work on getting 2&4 close by adjusting them closed more, then go after #1.

 

[bronko37]

1. Adjust Cylinder 1 to match cylinder 3 -- Adjust Idle

2. Adjust Cylinder 2 to match cylinder 4 -- Adjust Idle

3. Adjust Cylinder 4 (which controls both 4&2 Simultaneously) so the left bank matches the right bank -- Adjust idle

May need to go through this sequence a couple times to get it all dialed in. Remember, make small little adjustments and "blip" the throttle in between each adjustment.

 

[dshearer]

Thanks for all of the help everyone I'll follow up and let you know what's happens

 

[dshearer]

Ok, I'm back at it swapped intake horns from 2 to 3 same high vacuum on 3 and 2 still 7 lbs. Will idle at 15 lbs on 3, flick the throttle on the second time it will hand 2500 rpms till you shout it off. Then re-start it will idle again at 1000 rpms. So what should be my next move.

 

[slabghost]

bronko37 » Mon Feb 01, 2016 9:21 am[/url]":29yk1ucr]
1. Adjust Cylinder 1 to match cylinder 3 -- Adjust Idle

2. Adjust Cylinder 2 to match cylinder 4 -- Adjust Idle

3. Adjust Cylinder 4 (which controls both 4&2 Simultaneously) so the left bank matches the right bank -- Adjust idle

May need to go through this sequence a couple times to get it all dialed in. Remember, make small little adjustments and "blip" the throttle in between each adjustment.

Ok, I'm back at it swapped intake horns from 2 to 3 same high vacuum on 3 and 2 still 7 lbs. Will idle at 15 lbs on 3, flick the throttle on the second time it will hand 2500 rpms till you shout it off. Then re-start it will idle again at 1000 rpms. So what should be my next move.

 

[dshearer]

Reading back through everyone comments, on the throttle plates, 3 is completely closed and 2 was open around 1/16 or just a little more if the help one on my issue. Again thanks for the help

 

[slabghost]

Carb synch is adjusting the linkage.

 

[dshearer]

Understand I may be getting hung up the vacuum is there any wrong with 15 lbs as long they are all the same. Plus I did check throttle side they side up and ok on 3&2

 

[slabghost]

Higher the vacuum is the better the mileage and power. Low vacuum is not good. Where are you measuring the vacuum?

 

[dshearer]

Pulling from the bottom of intake horns, getting them them closer, flick the throttle about 25% it will idle down then flick the throttle 50% it will hang up at 2500 rpms then turn it of and re-start it will idle again. But getting harder to start.

 

[dshearer]

Punlink from bottom of the intake horns, getting it closer flick the throttle 25% will idle back down, flick the throttle 50% it will hang at 2500 rpms. Not sure we're to go from here, but it getting harder to start.

 

[slabghost]

Stay at the 25% until you have them all pretty close. Are you using a single gauge or a manifold of 4 gauges? Did you verify they read the same at the same port and rpm? You might want to put a charger on the battery and let it build back up. Idle and short revs along with repeated starting will drain the battery pretty quick. Pull the top of the air cleaner box and check the bottom of the plenum. If it's wet with fuel that may be the cause of hanging high idle.

 

[bronko37]

Your slides are sticking. When peen you blip the throttle initially it's not high on the rpm range so it goes back. When you open it a bit more you create more vaccume and it lifts the slides to open the main jet. But they are "sticky" so they are getting hung up and not returning. The good news is it's a pretty easy fix but you may need to remove the carbs from the bike. Would certainly make it easier to wrestle with.

 

[bronko37]

slabghost » Tue Feb 02, 2016 6:43 pm[/url]":j7kbvlig]
Stay at the 25% until you have them all pretty close. Are you using a single gauge or a manifold of 4 gauges? Did you verify they read the same at the same port and rpm? You might want to put a charger on the battery and let it build back up. Idle and short revs along with repeated starting will drain the battery pretty quick. Pull the top of the air cleaner box and check the bottom of the plenum. If it's wet with fuel that may be the cause of hanging high idle.

Also true...