good spark, compression, and carbs.. WTF!!

[Kitten Tooth]

Ok, i have had this 1981 GS650G sitting in my garage. Im at a total loss on what i can do for it now. Note, no airfilter and i didnt change the oil after it sat without being prepared for storage. The guy said he wanted the carbs rebuilt. I cleaned and rebuilt the carbs, they were dirty as hell. I cleaned and set the spark plugs to the propper gap. i got 130-140PSI compression. cylinders 1 and 3 fire great. header from cylinder 2 takes longer to get cold and the pipe coming from cylinder 4 doesnt get hot till probably like 5 minutes after starting. The bike boggs out really bad when you try to revv it after its been running for a good 3 minutes. He has a plastic fuel shut off valve on the tank coming out of the petcock. Fuel is brand new, i just flushed the tank. There was no vacuum line on the valve so i put one on but it didnt change anything. All the diaphragms have a wonderful seal. None of the needles are sticking in the seats and all carbs have fuel in them. When you spray starter fluid in the intake while its running with the throttle open, it revvs up fine. I also have spark on all 4 cylinders. I dont know what to do at this point and any help would be appreciated. I know its a carb issue since it will revv when starter fluid is sprayed in but i dont know what else could be wrong with them.

Thanks guys,
KT

[Octain]

Put NEW plugs in it.

[BassCliff]

Hi,

Did you completely disassemble the carbs ( LIKE THIS ), soak them in carb dip for 24 hours each, then reassemble them with a set of O-rings from http://cycleorings.com?

With stock jetting, these bike do not run well without the airbox/air filter installed. It needs some kind of air restriction or else it is way too lean and will exhibit the symptoms you describe. Did you check the rest of the air intake system for leaks? New carb boots and intake O-rings?

Thank you for your indulgence,

BassCliff

[Big T]

Cylinder #2 is related to a bad petcock. Did the #2 spark plug look extra black?

Before you do anything else, check the oil level. Then, take off the oil filler cap and see if it smells like gas. If it does, change the oil immediately

#4 probably needs some more cleaning

As for it now revving up, put your hand over the intake hole (where the air filter would be) and see if it revs up better. If so, put in a new air filter and see what happens

[Octain]

My 650 wouldnt rev with box installed and no filter. Just bogged as you twisted the throttle.
Idled ok but thats about it.
I agree with oil comments as well.

[Kitten Tooth]

Well... i guess this thread was kinda pointless. the guy came and got his bike today. Made a quick 200 bucks I put my hand over the intake for the filter and it revved like a brand new bike the plugs were new i guess. He put them in when he gave me the bike to work on. Im going to be honest, before he took it and when i got it running nice, i was totally jealous that it wasnt mine oh well, still made that sweet, sweet casheh cash!!