83 GL1100 chuffing and chirping

[Scooter66]

Hey all, I acquired an 83 Aspencade a couple months back and proceeded to put many hours into getting her back on the road. When I bought it, it looked like it was left for dead. Oxidized paint, flat tires, no battery, mouse nests, you get the picture.So, the bike is on the road and running great for the most part, except this CHUFFING issue I have between 2200 and 3000 RPM. Anything above and below that, the bike runs great. If you are city driving, thats where the bike struggles ,until you can get the revs up over that 3000 mark, then its smooth sailing. I have checked everything I can think of or read about and I can't solve the problem. Heres a breakdown of the work done;
new timing belts
all fluids flushed
petcock and pickup lines cleaned
tank inspected-clean
fuel pump disassembled and cleaned
carbs removed disassembled and cleaned. No visible issues
valve clearance checked
new plugs
new fuel filter
new air filter

I've tried various octanes of fuel,doesnt matter which. One of the idle jets was set to 1/14 turns out and the 3 others were 2 turns out, which i found suspect. All set as of now to 2 1/2 out.
Plugs are currently an ash color.
One other thing odd is the revs can fluctuate with the choke on full. It will hover around 1500 rpm and then shoot up to 3500 after a minute or so from a cold start up.
From what I've read this chuffing which seems to come from the airbox and high pitched chirping which seems to come from the right exhaust seems common on these bikes. It chuffs and chirps more when riding double, I assume from the extra load on the motor.
I have hit a wall on this issue. Whats next, coils? I am absolutely perplexed.
I would really like to get this running as it should. My dad owned this same year and model when I was a teenager,so it has sentimental value to me.
Any input would be greatly appreciated.

[WingAdmin]

Chuffing out the intake is generally a compression or ignition charge inappropriately being sent up - which could be a sticking intake valve, or a head gasket leaking between cylinders.

Pull the carbs and see if you have marks on the insides of one of the intake runners that would indicate that it is the problem cylinder.

[biguns]

I would do a compression check first, ash colored plugs are rich are they all the same color? , did you synchronize and check left to right balance? I know getting carbs right is difficult, first time it took me 3 times in and out to get mine right.

[Scooter66]

Thanks for the replies. I haven't done a compression test yet. My tester doesn't have the right size to fit, so will have to borrow one. I did notice while putting the carbs back on that the valve tubes had flat o rings. Not sure if they are making a good seal so I ordered new ones. I did a test today with the bike warm and idling. I sprayed quick start around the head gaskets and then did the same with propane. There was no fluctuations in rpm. If it was head gasket leaks, would the rpm not have gone up with this test?
I checked the plugs yesterday and they were all white. I tightened the idle jets all by a half turn and rode the bike for a while and checked them again. They are darker now. A cream color.
The quest continues. I ll try the o rings and then head gaskets after that I guess.

[biguns]

Just do a compression check first before head gaskets, if ok and your still suspicious you can borrow a head gasket leak detector from an auto parts store or just buy one from amazon for 30-40 bucks, the kind with the fluid that changes color, need to remove tank to get access to the radiator cap.
If it were mine with those symptoms I would suspect carburetor issues.
Good luck

[Scooter66]

The carbs are clean as a whistle. The floats were set all the same. Gaskets good etc. I can give it another go. The bike came with a few extra parts. One was a single head gasket. There was no info on that. The bike was given to this guy and he didn't know much about it. There's was a receipt for a carb rebuild with new kits in 2019. I will get them synced after I solve this chuffing issue. Thanks biguns, I will try your suggestions. Cheers.

[JoBoy68]

When the carbs were done were the air cut-off valves replaced ? on my 83 the air cut-off valves did not come with the carb kit .their job is to prevent backfiring when downshifting and if these air cut-off valves are shot they work on vacuum and as we all know vacuum leaks can do weird things

[WingAdmin]

I agree, knowing now that the carbs were recently done, that does tend to point the spotlight that way.

[Scooter66]

Geez, I can't picture where the air cutoff valves are??

[JoBoy68]

The air cut-off valves are on the right side of each carb look for the cover in the pic above and they look like heavy-duty accelerator pumps

[Scooter66]

OK, I ll pull the carbs again and disassemble as well as the air cutoff valves. Thanks again for the input.

[Artur POLSKA]

I can't set the carburetors on my motorcycle. Its maximum speed is 140 km / h. Engine does not run smoothly. What could be wrong? The carburetors were washed and boiled in distilled water with various additives. I chose this topic because it seemed similar to me, and I did not want to start a new one.I have posted a link with the video.After // remove spaces
https:// youtube.com/shorts/TmIRSsf_pOg?feature=share

[Scooter66]

Can you decipher where the clicking noise is coming from? That could be a valve. My bike makes more of a puffing sound, like it's getting too much air.

[Artur POLSKA]

These sounds are from the carburetors. Seems like there is an air problem. What you see in the video is the maximum RPM I can get on this bike. I have no idea what could be causing this.As for the head, both surfaces are ground together with all valves and valve seats.

[Scooter66]

You should post this as a new topic. Check the air cutoff valves and the accelerator pump. Our problem are similar for sure. I've been away, so I haven't been able to pull my carbs. Our carbs are sucking air in somewhere. Pull them and start over again. Check for head gasket leaks as well.

[Scooter66]

Hey guys. I finally got to pulling the carbs again. The air cut off valves all have a spot on them where they are worn. If you hold them to the light, you can see through them. I'm going to repair this and then give a go. I'm optimistic this is the issue. I ll update later. Thanks for your help!

[biguns]

Hey guys. I finally got to pulling the carbs again. The air cut off valves all have a spot on them where they are worn. If you hold them to the light, you can see through them. I'm going to repair this and then give a go. I'm optimistic this is the issue. I ll update later. Thanks for your help!

Thats great, I think that will do allot but something else now that they are off is fill the bowls on the bench and check all 4 accelerator pump nozzles to be sure they are spraying if you havent already done that. If it were me I would use a CC cup or other measuring device and set the floats by filling then emptying the bowls to get them exact and look for leaks, I use a 5 foot hose and a funnel to simulate the 3 pounds of pump pressure

[Scooter66]

Carbs were pulled and I patched the holes in the cutoff valves with plasti-dip. It covered them well. I tested the accelerator pump and it was shooting gas 4 feet in the air, so I thought that's working good. I did notice the boot that goes on the accelerator pump rod was torn up. I put it back on without it, reassembled the carbs and installed on the bike. Now it runs awful. The rpm keeps spiking, the choke stopped working, it backfires and its hard to start. Holy moly!! I have never had so much trouble with carbs in my life. I ordered new cutoff valves. So, off they come again! I'm curious of the necessity of the accelerator pump boot. While bike was running, I sprayed start fluid around the head gaskets again. This time I got a fluctuation on the left side. It would go up 10-30 rpm while spraying.... Hmmmm....

[tomos]

Hi I hope you have made progress and got bike running again?My experience with my bike and that sound, misfire is most likely problem.Coils,hi voltage cables, spark plugs boots and spark plugs must be checked.I had a new cable that was jumping spark to carbs.So I installed clear fuel tube over all four cables and problem with jumping spark was gone.
However,you have made huge mess with carbs ,so my suggestion is to get them out AGAIN .
GET NEW CARBS REBUILD KIT FROM TRUSTED SOURCE.That is important because gasket thickness and quality is most important.Get through carbs step by step install all brand new rubber parts and make sure that rubber boots that connect carbs with cylinder head have no cracks,no leaks.Instal new gaskets at the bottom of all four boots and make sure they don't jump out of place.
I hope this helps you.
Regards Zoran

[JoBoy68]

did you do the air cut off valves when you did the carbs they can cause all the problems you are talking about

[tomos]

Ok,have you been able to get bike fixed?What was problem ?
Please update.
Regards Zoran