major loss of power in 3rd

[smurf_e_lee]

Hey everyone, I searched everywhere on this site but couldn't find an exact answer or anyone that had the same exact problem. here is my situation
I was riding today in the south bay cal from the stunt bikes hosted by 94.9 and It was all a good day but as soon as i left all hell broke loose, well felt like it anyways. I was riding previously that day about about an hour (everything good, little trouble turning over but after about 3 tries purred great) After leaving I was riding in third (about 30-35 mph) and the bike started to buck, I started to give her a little more throttle but every time i did it would just lose more RPM. eventually it stalled after i downshifted to 2nd. Pulled her over and checked it out, nothing seemed wrong from a quick overlook. Thought it was something stupid like i forgot to check gas but nope it was all good. tired to start again. (mis start about twice) then started right up. This happened about 2 times more, I noticed that it happened to do this around 3200-3500 rpm. in 3rd and 4th. I started running at higher RPM's 4000-4500 on bike set to RESERVE fuel, NO problems.  here is the lowdown in the bike

I bought this from my neighbor for pretty cheap because they "didnt want to ride"
06 gs500f
130 miles on it (210) after today.
all stock parts
Neighbor actually had her sitting in the garage for about a year without riding.

after i picked it up i figured since it sat there would have an oil change done and a chain clean and lube (I didn't do it had someone do it) but that was it. I was riding with a couple buddies and they struck me with a question that im not sure if it would even be a problem at all but asked if I ever put gas in the bike (because its still low miles) i got the bike with a tank of gas in it (they said they put gas in it for me before I bought it) but it might have been sitting in there for a year or so.

Can anyone help me with some ideas that I can look for ( i am new to bikes/ as well as working with engines) I have no idea where to start.

[jrains89]

hey, i just bought a 2004 gs500f with only 256 miles on it, and i'm in the same boat. both of our bikes sat a long time. you need to rebuild your carbs. you probably have clogged jets, which causes the weird drop in rpm when you give it gas at idle.

[yamahonkawazuki]

check  the carbs, they may need a bit of a cleaning. that aside, you may have a fuel starvation issue. meh i cannot remember the exact name or description,  but at sustained rpms, this sometimes happens. relieved by setting petcock on prime or by opening fuel cap, and running ( which can be dangerous to do btw

[ohgood]

DONT TEAR INTO YOUR CARBS YET

get a 5 gallon gas can, and drain your float bowls into it. there is one screw under each carb with a spigot that you can attach a 1/4" hose to. all of it. make your tank empty !

give the gas to your neighbor for his lawnmower, but definitely -not- his car

now you want to check your TANK petcock and ensure that it's completely vertical. if it's slightly turned, it will starve your carbs. there are two screws that hold it in place under your seat. 12mm or so, don't remember. don't loose the rubber bumper at the front of the tank. it keeps things quiet and secure.

get fresh 87 octane (no, 99 really isn't better, it's WORSE!) and fill the tank. set your petcock to PRIME, and give it a minute or so, then thumb the starter. she should fire up.

after warming up, and the bike is NOT choked, if it still stumbles in the same place, i'd suspect a bad plug wire or plug. odd bucking at a certain rpm is usually electrical related, and the vibration makes it happen.

if you are certain all your electrics are good and tight, sure, clean your carbs. just know you'll likely have to send off to the buddha for help if you're not meticulous with the re-assembly.