have you fully stripped them ? they'll need a full strip down and check for ware and make sure all the drillings are clear, also the diaghrams are not split. make sure the needles arn't loose in the slides.
i had a chop with a gsx 1260 engine in it that had blown the head gasket, i couldn't find a new one at the time so i made one from copper sheet. i was dead chuffed with it i didn't want to put it on the engine
you said you fitted a second set of carbs and it was fine but when you put the first set back on it over reved, so the problem lies with the first set of carbs.
i tried an RF carrier in a 600 bandit wheel and it didn't fit but i didn't know what year both parts where off. i have fitted a 1980 gsx 750 et carrier to a 1200 bandit wheel as its slightly shorter so i can line up the chain with an off set front sprocket.
yeah their is, ive worked for a few dealers and some have the tool others dont. even Suzuki have a tool for installing valve guide seals, they use the tool for removing/fitting the valve guide, 09916-44310
its been a long time since i fitted any stem seals but the OEM ones ive fitted in the past have a metal insert, theirs no way you could push them on with your thumb as you risk damaging the top sealing lip where the spring sits, i had to use the factory tool to install them.
ive just reread your first post wraith (im dyslexic), you mean the two bits that wrap around the cylinders ? they are for crash protection as they can be hidden behind a fairing, but they are quite stiff so they will help to keep the frame ridged. theirs nowt stopping you leaving them off but it might not help the handling !!!!
do you mean the two frame rails that cradle under the engine ? if so suzuki fitted them for a reason to give the frame strength. without them it will flex and their will be only the two engine mounts at the rear.