GS550 still running bad

[Anonymous]

Hey guys, I need some more help with my 550. after carefull poking around I discovered my running problem (top speed of 65 and nothing above about 6000 rpm) is due to cylinder #2 being pretty much dead. I pulled off the carbs again, and replaced that carb with one of my spares that I rebuilt before installing, and I still have a dead cylinder. It's gotta be fuel cause I check for leaks with an un-lit propane torch, and if I give her propane in the carb mouth she'll take right off. needless to say no air leaks either. anything in particular that is a problem with these carbs? all parts are new (jets, o rings, and such). any other possibilities? thanks. Matt

[WifeofDink]

You don't mention if you have replaced the spark plugs, if you have then check the plug lead to that cylinder paying particular attention to where the plug lead attaches to the cap

[Anonymous]

Swap plug and leads over for cylinders #2 and #3. They both run off the same coil and fire at the same time. This will elliminate coil, plug, lead and plug cap. Remove the drain screw from the float bowl. Does fuel run out ? Check your float hights. Swap all the components from carb #2 with a known working carb, say #1. It doesn't take long, maybe an hour. Does the fault travel to cylinder #1? It might seem like too much effort but again, its all a process of elimination. I have been rebuilding my 78 GS750 for about 18 months now (on and off) and its just about done. This process of elimination method is sometimes the best way, although not strictly speaking the most scientific way. But it always gets results. Good luck.

[Anonymous]

Swap plug and leads over for cylinders #2 and #3. They both run off the same coil and fire at the same time. This will elliminate coil, plug, lead and plug cap. Remove the drain screw from the float bowl. Does fuel run out ? Check your float hights. Swap all the components from carb #2 with a known working carb, say #1. It doesn't take long, maybe an hour. Does the fault travel to cylinder #1? It might seem like too much effort but again, its all a process of elimination. I have been rebuilding my 78 GS750 for about 18 months now (on and off) and its just about done. This process of elimination method is sometimes the best way, although not strictly speaking the most scientific way. But it always gets results. Good luck.

[Anonymous]

before you do all of the above, check your compression