Adjusting rebuilt carbs on GL1100 Goldwing

I just rebuilt the carburetors on my GL1100 and reinstalled them on the bike. The bike in running but it won’t idle lower than 2500rpm’s.
Should I try synchronizing  the carburetors first and then adjust the fuel/air mixture pilot screws to fine tune?
The Clymer manual says I need to buy a portable tachometer when adjusting the pilot screws. Is this absolutely necessary?
Thanks for your help

Hey Jeff

If your bike won’t drop down below 2500rpms then you most likely have a sync issue. Before you start messing with the sync do the following:

1 – Make sure your choke isn’t sticking or otherwise on. (Obvious, but a common issue)

2 – Make sure all your mixture screws are set the same. It doesn’t matter if they are set spot on, just make sure they are all set the same. Around 1.5 turns out from seated is probably a good ballpark for your bike, but you have the clymer, so set them to whatever it recommends for the stock setting.

3 – Make sure your throttle cable adjustment isn’t too tight. Verify by adjusting it loose and making sure the throttle mechanism on the carbs is hitting the idle adjustment bolt.

4 – Make sure your idle is turned all the way out.

If the above is all good and the bike is still running fast then it is time to sync the carbs.

I have a carb synchronizing article in the works. Once I get it online I can direct you to it. But you will need a proper tool/instrument to do a good job.

You do not need a portable tach to set the pilot screws. Just a keen sense of hearing to note when a change is affecting your idle speed.

Thanks for the quick response Evan.
1. The choke is working good.
2. I set the mixture screws to the clymer manual suggested settings to 1 1/4 turns out.
3. The throttle cable is working good and nothing is holding it up.
4. I turned the idle all the way out. The bike is running around 2000rpms now.

Does the float bowl adjustments have anything to do with the idle?

I have a 4 gauge sync kit and I’m going to sync the carbs today.

I will let you know the results.

Thanks for you help.

If your floats aren’t sealing well and the bowls are overfilling that could cause the same problem – you’ll get some extra gas into the cylinder.

If you’ve got the sync gauges I would just do a sync and see where it stands. Even a very slight differences in throttle plate adjustment (synchronization) can cause racing idle or hunting idle.

Please let me know how it goes.

I synced the carbs and the idle came down like you said it would. I adjusted the idle to 1000rpms and it idles very smooth.

When I rode the bike to work yesterday I noticed a hesitation in the middle throttle range. It seems to get worse as the bike warms up. I’m going to run a fresh tank of gas and add some Seafoam to see if this helps. Please let me know if you have any suggestions for this issue.

I rode the bike about 100 miles over the past few days and the hesitation is really bad at 1/4 throttle. Like I said in my last post-It get worse as the bike warms up. The bike pulls hard when I open the throttle but when I ride at a consistent speed at that 1/4 throttle mark it really runs bad.
Could the floats be causing this problem?

Are you running a stock exhaust? What is the condition of your air filter? Has the bike always been in your area/elevation?

If your exhaust has a leak (or your intake) it can cause odd problems like this. Verify the integrity of the exhaust and make sure it isn’t leaking or rusted through anywhere.

Hesitation as you describe can be caused by a variety of things. Around 1/4 throttle is where fuel metering is switching from the pilot circuit to the main circuit. A common cause is incorrect jetting. You may need to up the size of the main jets. What size jets do you have in there now?

How many miles are on your bike – are the main needles worn? They become hour-glassed over time rather than a straight taper.

Let me give you a little history of the bike.
I’ve owned the Wing for the past 7 years and I’ve put 35,000 miles on it. It currently has 63,000 miles.
I started having this problem last June and up until then I’ve never had a problem with the engine.
In August of 2009 I changed:
1. The timing belts
2. The air filter
3. The fuel filter
4. The fuel lines
5. The spark plugs
When I rebuilt the carbs I replaced all the jets that came with the Napco carb kit. Everything on the bike seems to be stock. I’ll double check the o-rings on the intake manifolds to make sure I don’t have a vacuum leak.

I am running the stock exhaust and it’s in very good condition.
I live in Michigan and I bought the bike from a guy in Ohio and he owned it for 8 years.
The only reason I rebuilt the carbs is because a mechanic at the Honda dealer told me it was a carburetor issue.

I really appreciate all your help.


The problem is definitely carb related.

Are you sure the jets that were originally in the carbs were the same sizes as the ones provided in the rebuild kits?

You’re on the right track checking for vacuum leaks. You can spray WD40 all around the rubber manifolds and listen for any running change from the bike – if any gets sucked in it’ll rev higher.

I would also recommend double checking your float heights. They might be slightly high, keeping too much fuel in the bowl, causing a slight flooding condition.

Keep plugging away, it’ll be worth it!

I took the carbs off and put the old jets back in.
I lowered the floats so they would hang lower in the bowls and I re-synced the carbs.
The bike is still doing the same thing. A few people on the Goldwingdocs site think it might be a CV Slide issue. Is there a way to check the function of the slides when they’re on the bike?

I put 300 miles on the bike in the last week and the only time I have trouble is still at the 1/4 throttle range. It does the same thing when I accelerate and decelerate.

I checked the CV Slides and they move freely in the chamber. I did not mix the CV Slides up when I rebuilt the carbs.

I didn’t change the Air Cut-Off Valves when I rebuilt the carbs. I checked on the Randakk’s site and they said this could be part of the problem along with the CV Slides.

When I get the bike over 6000rpm it starts to hesitate the same way as the 1/4 throttle issue.

Sounds like you’ve got a bit of a pickle in your hands.

It also sounds like you’re close to solving it. The air cut off valves seem like a likely culprit. The symptoms match up as well – the cut off valves control air flow in the pilot circuit, so up to about 1/4 throttle. They also should activate in a high vacuum or air velocity condition, such as full throttle. If they aren’t working properly I can see this causing your problem.

If the problem persists past the air valve and I was in your shoes I would probably start watching eBay for a spare set of carbs for the bike. Rather than replacing each of the carb parts individually it’ll be much more cost effective to replace the entire set with another good condition rack. If it proves not to be the problem then you can resell them or keep them long term as spares.

Someone once told me “carbs are more of a magic than a science” – and it has always stuck with me. Sometimes it seems like voodoo art getting all the kinks worked out!

Keep working at it and keep me posted!

Evan Fell

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