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I have a 1979 GS750E. It does not like to run. I have had it to 3 places for repair and still am not satisfied with how it runs. The last place told me it was just cold blooded. I can work on cars but this is my first motorcycle and I have little knowledge about repairing one. Any ideas as to what the problem is would be greatly appreciated. I have hardly ridden it the past 3 years I have owned it since I am afraid I will get stranded somewhere. Prior to my ownership it was driven a lot during the summer. I am tired of dumping money into the bike. The symptoms, etc. I will list have been the same for the past 3 years. The bike has 20,000 miles on it.
Symptoms At Startup:
*Will not start if it sits for about a week. If it sits I have to constantly choke it, running the battery dead, charge the battery, run it half dead, then it starts.
*After it starts, you can not rev the engine for about 5 minutes or it will die.
*If I let it set and run with the choke on it will run at about 1500RPM for a while and then backfire and smoke for a while, usually black, then it will rev up to 3000RPM. This takes 15+ minutes.
Drivability symptoms:
*If I do not let it "warm up" until it goes to the 3000RPM and drive it, it wants to die when giving it throttle.
*If I can get it going down the road it will either have no power, running smoothly, or will be backfiring and jerky to ride.
*It seems like it fouls the plugs or is running on 2 cylinders because when it has no power, if I just about redline it for about 2 blocks it will backfire a few times and then I have twice the power. This seems to happen about every time I ride it.
*At highway speeds on flat road I can not keep it at steady speed, with steady throttle rpm's drop sometimes
Other symptoms/things I have noticed:
*Even after warmed up and running "good", if I give it quick throttle it will instantly die.
*The plugs get fouled a lot. They are extremely black, almost like a carbon buildup. Sometimes they are flooded with gas. After the plugs are replaced it runs better for about 3 times of riding.
*One side of the exhaust is missing about 4 inches of baffle because the muffler rusted out in the back. Both mufflers are black where the exhaust comes out.
*If air filter is removed completely it seems to run a little better
*I hooked a timing light to the wires to check for spark and the two inside must be linked and the two outside must be linked. I can not remember which, but I think the inside cylinders sparked a lot faster than the outside ones at startup. If I remember correctly the outside cylinders sparked a lot more intermittently.
*I also noticed that I have vacuum type lines that look like they come from the carbs just hanging down over the starter cover, prossibly for overflow of gas?
Repairs done to engine and what I have been told by the mechanics:
2 Years Ago:
*Carbs cleaned and kits put in because two were leaking
*Carbs synchronized
*New Air Filter - old one was flaking apart
*New plugs
*Check points and condenser - They are fine
*Oil and filter change
Last year:
*Carbs cleaned and synchronized -everything looked good
*Air filter looked good
*Not getting enough air - took some rubber thing off the air filter box to allow more air flow - was told it was to keep dust out but not needed
*New valve cover gasket
*Valves adjusted
*checked timing of engine - fine
*Points and condenser - good condition
*Choke sticks on carb - cleaned and have to manually push it down sometimes, have to keep an eye on it
*New plugs
*Oil and filter change
I either run premium unleaded or regular unleaded gasoline because I was told ethanol was not good for the seals in the carburetors. I have tried seafoam and it did not help. I always put fuel stabilizer in at each fill because I was told to do so by a mechanic. I do not know much about points, condenser, or the coils on a motorcycle, but I was thinking that one of these may be my problem. Any help would be greatly appreciated. Thank you. Fred.
Symptoms At Startup:
*Will not start if it sits for about a week. If it sits I have to constantly choke it, running the battery dead, charge the battery, run it half dead, then it starts.
*After it starts, you can not rev the engine for about 5 minutes or it will die.
*If I let it set and run with the choke on it will run at about 1500RPM for a while and then backfire and smoke for a while, usually black, then it will rev up to 3000RPM. This takes 15+ minutes.
Drivability symptoms:
*If I do not let it "warm up" until it goes to the 3000RPM and drive it, it wants to die when giving it throttle.
*If I can get it going down the road it will either have no power, running smoothly, or will be backfiring and jerky to ride.
*It seems like it fouls the plugs or is running on 2 cylinders because when it has no power, if I just about redline it for about 2 blocks it will backfire a few times and then I have twice the power. This seems to happen about every time I ride it.
*At highway speeds on flat road I can not keep it at steady speed, with steady throttle rpm's drop sometimes
Other symptoms/things I have noticed:
*Even after warmed up and running "good", if I give it quick throttle it will instantly die.
*The plugs get fouled a lot. They are extremely black, almost like a carbon buildup. Sometimes they are flooded with gas. After the plugs are replaced it runs better for about 3 times of riding.
*One side of the exhaust is missing about 4 inches of baffle because the muffler rusted out in the back. Both mufflers are black where the exhaust comes out.
*If air filter is removed completely it seems to run a little better
*I hooked a timing light to the wires to check for spark and the two inside must be linked and the two outside must be linked. I can not remember which, but I think the inside cylinders sparked a lot faster than the outside ones at startup. If I remember correctly the outside cylinders sparked a lot more intermittently.
*I also noticed that I have vacuum type lines that look like they come from the carbs just hanging down over the starter cover, prossibly for overflow of gas?
Repairs done to engine and what I have been told by the mechanics:
2 Years Ago:
*Carbs cleaned and kits put in because two were leaking
*Carbs synchronized
*New Air Filter - old one was flaking apart
*New plugs
*Check points and condenser - They are fine
*Oil and filter change
Last year:
*Carbs cleaned and synchronized -everything looked good
*Air filter looked good
*Not getting enough air - took some rubber thing off the air filter box to allow more air flow - was told it was to keep dust out but not needed
*New valve cover gasket
*Valves adjusted
*checked timing of engine - fine
*Points and condenser - good condition
*Choke sticks on carb - cleaned and have to manually push it down sometimes, have to keep an eye on it
*New plugs
*Oil and filter change
I either run premium unleaded or regular unleaded gasoline because I was told ethanol was not good for the seals in the carburetors. I have tried seafoam and it did not help. I always put fuel stabilizer in at each fill because I was told to do so by a mechanic. I do not know much about points, condenser, or the coils on a motorcycle, but I was thinking that one of these may be my problem. Any help would be greatly appreciated. Thank you. Fred.
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