gs450 - still not running right

[bren]

i'm getting frustrated, i need help thinking through this. let me just put out some basic obvservations i've taken.

the left cylinder is way richer than the right one still.

the only way i can get it to idle evenly is to back the sync screw out really far. when i put the carbtune on there, it shows much more vac pressure on the left cylinder. but if i sync it up, it idles unevenly, and it still takes a long time to come back down to idle when i blip it.

the right pipe is running way hotter than the left one.

the left side was puffing intermittently at idle when it got really warmed up.

i looked at the plugs after about 10 or 15 minutes of mostly idling. the left plug is starting to turn brown. the right one still looks basically brand new.

• what i'm trying to understand is, is the left cylinder too rich? or is the right cylinder too lean? how can you tell?
• if the cylinders are this different, then, if there's an air leak, it's gotta be after the carbs, not in the airbox, right?
• this could be caused by the right carb still not being clean enough? or the right side float being too low? what else?

i'm looking for troubleshooting suggestions, thanks for reading

[Nessism]

Have you gone through all the items in the Newbie Mistake thread? Post up everything you have done.

[bren]

thanks, i read it again. i decided to start over on the carbs. i read through the carb dipping guide again, it says to leave the parts in there for 24 hours... the can says, 15-30 minutes. So maybe they didn't get clean enough the first time. I'm gonna leave them in there for the full length specified in the guide.

other than that, i did the carb o-rings, the valves, the boots, boot o-rings, even replaced the ignition, which turned out to just be for fun in the end. checked for air leaks with carb cleaner, for what that's worth. it's gotta just be that i didn't clean the carbs right. if that's not it, then i'm really at a loss.

[Big T]

The vacuum diaphragm on the fuel tap is bad and is dumping extra fuel into the left cylinder.

Test - remove the vacuum line from the fuel tap and plug it with a bolt. Run the bike on Prime and see if the issue is gone

[dgates1]

The vacuum diaphragm on the fuel tap is bad and is dumping extra fuel into the left cylinder.

Test - remove the vacuum line from the fuel tap and plug it with a bolt. Run the bike on Prime and see if the issue is gone

Agree with this. Simple test to eliminate the petcock.

[bren]

Agree with this. Simple test to eliminate the petcock.

sorry guys i've ruled that out. the petcock's not even on the bike right now. i'm running the bike off a gravity fed aux tank straight to the carbs