Runs like a dog

About 3 months ago I cleaned the carb jets because the bike had sat unused and the carbs flooded when I did try to ride it .
So bike was running well and then last week it started running like a dog . Wouldn't idle , died at the lights ,
just bad . So I drained the gas , put non ethanol gas with a heavy dose of seafoam in the tank . Bike started to run better .....
This morning it start o'k and revved well . So I am thinking problem solved . Not so fast !!! This afternoon I thought I'd go for a
longer ride and she is running like a dog again . I filled up with 6 gallons of non ethanol gas and no improvement .
Limped back to the garage and started pulling off the plastic
- pulled the plugs and they were all black
- fuel pump squirts one maybe 1/4 cup of gas and then stops when ignition turned on
- auto fuel valve previously removed
- sub air filter almost completely gone
- fuel appear to have been leaking out from carbs
- removed carbs , diaphragms appear intact but debris underneath ( sub filter ? )
- removed boots , while not cracked they are firm if not hard ( replace ? )
- just checked one carb so far , idle jet appears blocked

So at this early stage I am thinking .
new sub filter
remove diaphragms , clean below and reuse , or should I replace them ?
clean jets , do I need to replace bowl gaskets if they are not leaking
while here remove pair stuff below carbs . need blocking plates
should I replace cab boots ?
Anything else I should check / replace while here ????

Sounds like you checked most of the items....
1) Replace the sub air filter... order an extra while you are at it, their cheap.
2) Where is the fuel leaking from the carbs? If it is the bowl gaskets... replace the ones that are leaking.
3) Carefully remove the vacuum pistons (diaphragms) and clean! If they are not split or have holes in them, reuse them... they are about $100.00 a pop!
4) Replace the carb isolators...(boots) If they are hard, they may be allowing a vacuum leak... their about $9.00 each and well worth it to eliminate possible problems.
5) Remove the idle jets and high speed jets from all carbs... along with the carb bowls, boil them in pine sole and water to clean them.
Do not try to clean them with an object that is hard, it could damage the jets. The carb gaskets are a little pricy, if you want, you can soak the old ones in alcohol to rejuvenate them somewhat.
6) If you are going to go through the trouble of messing with the pair system, try removing the pair valves and clean them. They can collect some oil over a period of time. Probably won't help removing them.
7) After reassembling the carbs, it probably will be necessary to sync them to get the best performance from your bike.
8) The most important thing you left out is the fuel filter. One of the symptoms you mentioned is the "poor" running in the afternoon. Running fairly good in cooler temps and not running well in warmer temps is one of the symptoms of vapor lock. If the fuel system is restricted in warm temperatures, the gas has a low boiling point and (can start near 80*). Make sure the fuel filter is good, and them make sure the fuel pump is delivering enough fuel to feed all four carbs. The amount (1/4 cup) you mentioned for the short burst the fuel pump operates when you first turn the key should be adequate, but with warmer temps, that may change.

Vinny pretty much covered it but I will add that if you do decide to remove your pair system, any block off plates from ebay that "look" like they will fit, probably will. When I went searching for plates after a failed attempt to make them myself I found two different kinds on ebay. Neither were listed as fitting the ST. One type was obviously wrong because they were large and square but the others were the right oval shape and bolted right up. I think they were for a gsxr maybe...

Vinny ,
Thanks very much for the feedback .

Since the sub air filter seems to have disintegrated is there a chance those pieces were pulled into the carbs fouling the vacuum channels?

I have ordered new carb boots , sub air filter , fuel filter , and block off plates for Pair equipment removal .
Will hopefully get back to bike this weekend

I would do a complete tear-down if your going to the trouble to pull them again.Not that much more time to do.Maybe a couple hours
Adam's write-up is the most thorough. http://www.st-riders.net/index.php?topic=10249.0
Which means going to #40 Slow jet.MUCH better than stock. Fatter low and mid-range.

It sounds like you have done all the right things. But you did not mention about the air idle screw adjustments (At least two turns to start out) or syncing. I don't have the Honda tool for the air idle screw adjustment while running so I am for now stuck at two turns out for now.

As a note I just did my carb rebuild and re-jetting based on Adam's write up. Bike runs great but here are the very noticeable things right out of the gate. Even before syncing the motor ran smoother than before the work. Better power band across the board, better acceleration and better MPG.

Bike is now running great . I stripped down the carbs , blew out all the passages , new sub air filter , set the floats which were all about 9mm not 7mm
new bowl gaskets , new boots , new fuel filter . Didn't remove the Pair equipment . Maybe next time . Then synced the carbs with a
friends Twin max . So the main problem I found seems to have been the deteriorated sub air filter
Thanks for all your helpful suggestions

When I did my carbs a month or so ago I found the float level all over the board. From 7 to 9. Each was different.

Now I bet that is a good feeling to get it running again and you did it!!

Congratulations! Where do I send the diploma?

Did Adams write up need any additional pointers. I think my 94' needs this done. Any part numbers on the boots, jets, gaskets, etc available. Thanks, Rod