I was having an issue with the 60,000 mile GS1000G I keep in CA. It would not take throttle. As it was ridden, it would lose power, and accept less and less throttle. Got stuck climbing hills in first gear at 20 mph, and finally had it towed. I had left it on Prime previously, and allowed the crank case overfill badly. I did change the oil and filter, and cleaned the air filter. The problems persisted, but not as badly. Work kept me from riding or working on it for a good while. It would always start on the button and idle perfectly all day long. Would rev quick and cleanly without load. I was thinking low voltage or bad electronic box for the stock 1980 ignition.
Sunday, I took off the airbox and dismantled it for cleaning. It was pretty goopy in the lower side. Not so much where the vent line from the cylinder head goes into the top. That part of the airbox was completely clogged. Not with oil though. It was clogged on the slotted ends where the condensation and blowby is routed to the sides of the upper inside of the airbox. I believe that it was corrosion from 40 years of cold starts. I cleaned the narrow passages with a hack saw blade and coat hanger wire.
I don't know if you are familiar with the early G airbox, but it is a complicated heavy and clearly difficult to build item.
I took the carbs off. I could see that a clamp on the vacuum connection may have fouled the actuation bar on the enrichment circuit. Not certain. I did not fully dismantle the carbs. I did remove the float bowls and sprayed carb cleaner through the main and pilot air passages and verified it was coming out in the right places in the carb bodies. I was 100% sure the pilot circuit was 100% functional anyway.
The elastomer velocity stacks that seal the airbox to the carbs were pretty sticky and gummy. They were still flexible though, and they were cleaned. Checked the voltage on the DYNA coils. Only 8 volts with the ignition on and running lights head light and tail light on. It showed 12 at the battery with the ignition off. Didn't check battery voltage with all the draws with the ignition on. It was starting fine anyway.
I had suspected electrical, because I've never had a carb problem that affected all carbs the same at the same time. Another 1000G had a blocked air passage from the bell mouth to the emulsion tube and progression holes, but only that one cylinder had a problem.
In any case, I reassembled it, and it now is back to running perfectly. A completely blocked breather from the crank case was a shocker. I had noticed a split in the hose from the valve cover to the airbox and repaired that a month or so ago.
Anyway, if I think its fuel, its electric, and if I think its electric, its fuel, likely as not.
the crank case vent in the airbox will be checked on my other "G"s
https://imgur.com/gallery/iWbwMnY
Sunday, I took off the airbox and dismantled it for cleaning. It was pretty goopy in the lower side. Not so much where the vent line from the cylinder head goes into the top. That part of the airbox was completely clogged. Not with oil though. It was clogged on the slotted ends where the condensation and blowby is routed to the sides of the upper inside of the airbox. I believe that it was corrosion from 40 years of cold starts. I cleaned the narrow passages with a hack saw blade and coat hanger wire.
I don't know if you are familiar with the early G airbox, but it is a complicated heavy and clearly difficult to build item.
I took the carbs off. I could see that a clamp on the vacuum connection may have fouled the actuation bar on the enrichment circuit. Not certain. I did not fully dismantle the carbs. I did remove the float bowls and sprayed carb cleaner through the main and pilot air passages and verified it was coming out in the right places in the carb bodies. I was 100% sure the pilot circuit was 100% functional anyway.
The elastomer velocity stacks that seal the airbox to the carbs were pretty sticky and gummy. They were still flexible though, and they were cleaned. Checked the voltage on the DYNA coils. Only 8 volts with the ignition on and running lights head light and tail light on. It showed 12 at the battery with the ignition off. Didn't check battery voltage with all the draws with the ignition on. It was starting fine anyway.
I had suspected electrical, because I've never had a carb problem that affected all carbs the same at the same time. Another 1000G had a blocked air passage from the bell mouth to the emulsion tube and progression holes, but only that one cylinder had a problem.
In any case, I reassembled it, and it now is back to running perfectly. A completely blocked breather from the crank case was a shocker. I had noticed a split in the hose from the valve cover to the airbox and repaired that a month or so ago.
Anyway, if I think its fuel, its electric, and if I think its electric, its fuel, likely as not.
the crank case vent in the airbox will be checked on my other "G"s
https://imgur.com/gallery/iWbwMnY
