Newbie Carb problems (gs1100e won't rev)

[offthewall]

1982 GS 1100E (original owner). Bike had been sitting in garage for last 10 years.

Took carbs apart (following .pdf on this site) and cleaned everything except the "air screw" (seems to be some sort of cap over them).

Anyway, bike starts fine on choke. After a few warm up minutes, choke off and it idles fine at 1100 rpm. As soon as throttle is twisted engine dies.

Air box and filter on, boots to and from carbs tight and look in great shape.

Took air filter box off and looked into carbs while engine is running and the needle sliders on all four carbs do not rise (hence no fuel) when the throttle is opened. They just "quiver" rather than open up.

HELP! Please.

 

[earlfor]

Re: Newbie Carb problems (gs1100e won't rev)

Did you check the diaphrams in the CV's for dry rot, tears, pinholes etc?
If they are leaking, they arent going to work.

Earl

1982 GS 1100E (original owner). Bike had been sitting in garage for last 10 years.

Took carbs apart (following .pdf on this site) and cleaned everything except the "air screw" (seems to be some sort of cap over them).

Anyway, bike starts fine on choke. After a few warm up minutes, choke off and it idles fine at 1100 rpm. As soon as throttle is twisted engine dies.

Air box and filter on, boots to and from carbs tight and look in great shape.

Took air filter box off and looked into carbs while engine is running and the needle sliders on all four carbs do not rise (hence no fuel) when the throttle is opened. They just "quiver" rather than open up.

HELP! Please.

 

[offthewall]

Re: Newbie Carb problems (gs1100e won't rev)

Earl,

Boots certainly did not have any obvious tears or dry rot. They actually looked in good shape. Tomorrow I'll pull them out and check for pin holes. Are such small leaks in the CV boots common?

Did you check the diaphrams in the CV's for dry rot, tears, pinholes etc?
If they are leaking, they arent going to work.

Earl

1982 GS 1100E (original owner). Bike had been sitting in garage for last 10 years.

Took carbs apart (following .pdf on this site) and cleaned everything except the "air screw" (seems to be some sort of cap over them).

Anyway, bike starts fine on choke. After a few warm up minutes, choke off and it idles fine at 1100 rpm. As soon as throttle is twisted engine dies.

Air box and filter on, boots to and from carbs tight and look in great shape.

Took air filter box off and looked into carbs while engine is running and the needle sliders on all four carbs do not rise (hence no fuel) when the throttle is opened. They just "quiver" rather than open up.

HELP! Please.

 

[earlfor]

Re: Newbie Carb problems (gs1100e won't rev)

I'm not sure we're talking about the same thing. Boots are the induction tubes that hold the carbs to the cylinderhead and connect the carbs to the airbox. CV diaphrams are the thin rubber disks (diaphrams) that fit on top of the carb slides (inside the carb body and under the round carb cap)
If a bike has been sitting for some years, it is very common for them to become stiff, brittle and develop leaks.

Earl

Earl,

Boots certainly did not have any obvious tears or dry rot. They actually looked in good shape. Tomorrow I'll pull them out and check for pin holes. Are such small leaks in the CV boots common?

Did you check the diaphrams in the CV's for dry rot, tears, pinholes etc?
If they are leaking, they arent going to work.

Earl

1982 GS 1100E (original owner). Bike had been sitting in garage for last 10 years.

Took carbs apart (following .pdf on this site) and cleaned everything except the "air screw" (seems to be some sort of cap over them).

Anyway, bike starts fine on choke. After a few warm up minutes, choke off and it idles fine at 1100 rpm. As soon as throttle is twisted engine dies.

Air box and filter on, boots to and from carbs tight and look in great shape.

Took air filter box off and looked into carbs while engine is running and the needle sliders on all four carbs do not rise (hence no fuel) when the throttle is opened. They just "quiver" rather than open up.

HELP! Please.

 

[offthewall]

Re: Newbie Carb problems (gs1100e won't rev)

Earl,

Thanks for your help. I believe we are talking about the same thing. Excuse my incorrect terminology. The CV diaphrams looked soft, pliable, and no obvious holes or tears. My question was that if they are in fact leaking, it would have to be some very small holes or perferation since they look fine to the naked eye. I am going to check them out very carefully when I get home from work tonight.

I'm not sure we're talking about the same thing. Boots are the induction tubes that hold the carbs to the cylinderhead and connect the carbs to the airbox. CV diaphrams are the thin rubber disks (diaphrams) that fit on top of the carb slides (inside the carb body and under the round carb cap)
If a bike has been sitting for some years, it is very common for them to become stiff, brittle and develop leaks.

Earl

Earl,

Boots certainly did not have any obvious tears or dry rot. They actually looked in good shape. Tomorrow I'll pull them out and check for pin holes. Are such small leaks in the CV boots common?

Did you check the diaphrams in the CV's for dry rot, tears, pinholes etc?
If they are leaking, they arent going to work.

Earl

1982 GS 1100E (original owner). Bike had been sitting in garage for last 10 years.

Took carbs apart (following .pdf on this site) and cleaned everything except the "air screw" (seems to be some sort of cap over them).

Anyway, bike starts fine on choke. After a few warm up minutes, choke off and it idles fine at 1100 rpm. As soon as throttle is twisted engine dies.

Air box and filter on, boots to and from carbs tight and look in great shape.

Took air filter box off and looked into carbs while engine is running and the needle sliders on all four carbs do not rise (hence no fuel) when the throttle is opened. They just "quiver" rather than open up.

HELP! Please.

 

[Anonymous]

sounds like it isn't getting gas to me, as long as you haven't made any changes since it ran. Sounds like the main jet isn't getting gas into the engine.

I check my cv slides by manually pushing them up. You will know if there is a sufficient vaccuum seal from the diaphrams by the "sucking" sound and how slow they move back to position.

Check float levels and check the main jets for blockage.

 

[offthewall]

Yea that's my newbie conclusion as well. Why no gas is the question. I will check out the vacuum seal using your "sucking" procedure.

Won't the slides rise when the throttle is opened even if there is a fuel problem (jet/float)? I'm wondering if I fouled something up in the dissasembly/carb cleaning....

sounds like it isn't getting gas to me, as long as you haven't made any changes since it ran. Sounds like the main jet isn't getting gas into the engine.

I check my cv slides by manually pushing them up. You will know if there is a sufficient vaccuum seal from the diaphrams by the "sucking" sound and how slow they move back to position.

Check float levels and check the main jets for blockage.

 

[earlfor]

For the slides to rise, vacuum must increase. For vacuum to increase, rpm must increase and for that to happen, fuel flow must increase.

Earl

Won't the slides rise when the throttle is opened even if there is a fuel problem (jet/float)? I'm wondering if I fouled something up in the dissasembly/carb cleaning....

 

[Anonymous]

There is a little rubber plug that goes in below the main jet. If they aren't in place, it will start & idle fine, but it won't rev up. Speaking from experience, on a "80" GS 1000 E

 

[Anonymous]

He's right about the rubber plug. It's easy to forget it too, plus it's frustrating to take the damn things apart after putting them together. I'm on my 3rd set of carbs... took putting together 3 different sets (blended togther) to get my bike going right.

Logically speaking, if you haven't changed anything between the time you rode it until now, it must be somthing easy. Following the cleaning tutorial again should do it. What you know so far is that you get gas from the idle circuit and from the choke circuit. That leaves the main circuit really if you think about it.

Good luck.

 

[offthewall]

I really appreciate all the suggestions.

Just to keep you all up to date: Still not reving. It's not the CV diaphrams, they hold vacuum fine. My rubber plugs are in bad shape, I have ordered new ones (should be in today). The main jets are nice and clean. Fuel definitly get's into the bowls.

Is it possible that fuel is not flowing fast enough into the bowls? If I put the palm of my hand over one of the carbs, the engine will rev up by itself and excess fuel is obvious in the body of the carb.

Again thanks to all for the help.

He's right about the rubber plug. It's easy to forget it too, plus it's frustrating to take the damn things apart after putting them together. I'm on my 3rd set of carbs... took putting together 3 different sets (blended togther) to get my bike going right.

Logically speaking, if you haven't changed anything between the time you rode it until now, it must be somthing easy. Following the cleaning tutorial again should do it. What you know so far is that you get gas from the idle circuit and from the choke circuit. That leaves the main circuit really if you think about it.

Good luck.

 

[Anonymous]

are you testing this with the airbox on? My bike won't rev w/out the air cleaner on.

 

[Anonymous]

oh and you should have enough gas with the bowls filled to rev it.

 

[offthewall]

Yes I've had the air box on (what a PITA to take that thing in and out!). I just had it off last night to try and troubleshoot things a bit (the suggested CV diaphram vacuum and just to try to see what was going on inside there with the engine running).

are you testing this with the airbox on? My bike won't rev w/out the air cleaner on.

 

[offthewall]

Success!!!

Success!!!

Got the parts in today that I ordered last week when I first took a look into these carbs - 4 main jets, 4 pilot jets, and 4 RUBBER PLUGS.

Put them all in (even though the old jets cleaned up nicely) and YEA! It runs great. The rubber plugs were not in great shape and I think maybe leaking a bit. So that's what is came down to - 4 rubber plugs.

Thanks again to everyone in this thread.

Now I remember how bad the front fork was on this bike....

There is a little rubber plug that goes in below the main jet. If they aren't in place, it will start & idle fine, but it won't rev up. Speaking from experience, on a "80" GS 1000 E