The bike is a 95, with 01 carbs and has been my runner for 3+ yrs. Have put 3-4k on it.
Has yosh slip on Ti trioval pipe, stock filter in airbox and 132.5/20/1 washer/3 turns.
Carbs are clean, air filter is clean, valves are loose end of spec. Floats are set right, carbs are synched.
It used to bog at take off when its cold. But 2 mins after starting it and bogging 1-2 times, it will rev fine, make tons of power and like like a scalded dog.
It ran great Wednesday morning and evening inspite of the 2 mins of bogging in the beginning. Made 90 indicated or so on the way home Wednesday afternoon.
Thursday morning - starts, but makes no power, cant ride off on it, it starts and idles and sounds great, but the thing will not rev, and sounds hollow when you rev it, and it wont have any power to ride. Start to let out the clutch and it will stall. I can start it immediately, and it seems to not ever get to where it does not bog.

I'll post what it turns out to be. But any ideas are welcome.

Cool.
Buddha.

Zero power, hollow sound.  Those were symptoms of my bike when a coil failed. 

But if a coil failed wouldn't that require you to turn up the idle screw to get it in the proper range?

My guess:

Running on one cylinder. Suddenly caused by a clogged main jet or sticking needle. Or an electrical issue - faulty plug, loose connection to a coil. Basically carbs or electric, could be spun Piston rings lining up causing a loss of pressure.

I dont think its losing 1 cyl, but I'll check. I stripped a rotor cover bolt, so I have to drill it out and look at it today. Plus the coils on the frame.

The bike needs all the rings and everything else to be intact to idle. Idle makes the most vacuum, so I doubt it is related to the rings not sealing.

Clogged jets - definitely not. All clean and purty.

Back to the mystery now.

Cool.
Buddha.

My guess.....could be water in the gas, maybe someone took a pi** in your tank on weds night.

Ha ha sledge.
OK I'm ruling out electrical.
Why - on choke it revs to 4k-6k. On throttle it lacks power and not rev past ~3k.

Anyway - I am circling this theory. May explain most if not all symptoms.

Floats are high - one is worse than the other one but they are high. But I believe they are progressively getting worse. Also I am very reluctant to adjust floats on an 01+. That makes it likely that its the culprit. Maybe leaking, maybe an issue with one of em "sinking"

Cool.
Buddha.

Have you checked the temps of your exhaust header?  That would be a dead giveaway of a dead cylinder

Not really in this case, its running on both on choke. And revving to 6k, give it throttle and if it loses a cyl - which it probably would with a float that is too high - I certainly cant touch and tell which one is not firing before I lose a finger or 3 ...

Cool.
Buddha.

Hi  Buddha  ,   same problem here  2007  GS 500 F   ,   how high were the floats  ,  I  keep thinking  its electrical  ,  but  I am  making  black smoke  sometimes ,  however  spark plugs  look great  ,  I put trickle  charger  on every night when I get home ,  starts  right up  ,  leave sit for 12 hours ( no trickle charger on )  , and guess what  hard to start  ,  well  in the next day or two I am taking carbs off , taking them to whittier Kawasaki , and putting  new floats , new needles , new seats, new jets , clean carbs  complete , complete overhall  on carbs ,   as  all the above  parts are  9 years old ,  16,000  miles  on the clock ,  had new battery checked out ,  well  tonight  I am gonna check  the connection  on the starter and see if  loose .  anyways  let us know  how you are coming along .

Just for ruling things out....have you run a compression check?

gonna have to get a compression test kit

Buddha ,  do you have any oil in the airbox ?   maybe some blow-by , worn down piston rings  , how many miles on bike ?   air filter have some  engine oil on it ?  do to blow-by .

Air box is clean, no gas or oil on filter. Dry and clean.
Has tons of power, or has when it ran. Compression is probably fine.
I gotta check out my theory tomorow.
My floats may have been high enough to drown out the air intake jets in the filter mouth. AKA, essentially choked itself in gas, but maybe my dry sound - wasn't a very good description.
Cool.
Buddha.

hey  Buddha   ,    really  sounds  like   high float level  =  less  performance  .   what I am going to do is  buy brand new floats .  as  I can  smell  very rich mixture out tailpipe .  did you check starter wire to battery , make sure its  not loose .   

Quote from: Alan_nc on March 27, 2016, 01:43:01 AM
Just for ruling things out....have you run a compression check?

+1                                                                                                                                       

Rg500, it might not be necessary to buy new floats, you could try adjusting the ones you have

Quote from: lucas on March 25, 2016, 05:43:22 PM
Zero power, hollow sound.  Those were symptoms of my bike when a coil failed. 

But if a coil failed wouldn't that require you to turn up the idle screw to get it in the proper range?

+1

Buddha, you might be able to tell if you have a cold, dead cylinder by holding the back of your hand near the headers.  When I had a dead cylinder one header was 300 to 400 degrees Fahrenheit colder than the other.

Quote from: lucas on March 27, 2016, 10:11:36 PM
Rg500, it might not be necessary to buy new floats, you could try adjusting the ones you have

yes I will try that .  many thanks for the tip .

Quote from: lucas on March 27, 2016, 10:14:01 PM
Buddha, you might be able to tell if you have a cold, dead cylinder by holding the back of your hand near the headers.  When I had a dead cylinder one header was 300 to 400 degrees Fahrenheit colder than the other.

+2