Hi folks! Im having a nervous breakdown with my 2004 GS500F 

I i was on my way to work and the bike stalled at a red light. I tried to start it back for about 5-10 minutes until i gave up, so i called a tow truck. After the call (10-15 minutes after my last attempt) i figured ill give it one last try and it started on the first try! I cancelled the tow truck and went on my way in rush hour traffic. That morning, the bike stalled 2 other times and the exact same thing happened.

I tried to start it the morning after and then again no problem what so ever, its only after riding the bike 45min - 1hrs that it stalled again on stop. I figured it was the carburetor since the bike was making some backfiring puffs noises from time to time and there was distinct smell gasoline after medium to long rides. I also changed the air filter and the spark plugs 2 months ago.

So i sent it to the repair shop and the tech there agreed with me that it was probably due to a dirty carburetor so i spent 300$ rebuilding it. The Bike stalled on me again 30 minutes after getting it out of the garage but no more backfire puffs. I also waited 30 mins ant it started on the first try. Fortunately i was close to home.

I'm also not sure if my spark plug is screwed properly in its socket ill have to check that out not sure if that can make a bike stall tough.

So im thinking it might be running rich. What do you guyz think? can this make a bike stall and unable to start for 20-30 minutes? Where can i find the adjustment screw for the air mixture? i checked but i cant seem to find it. is there one adjustement screw per carburetor? or just one?

I must also say the weather here is really hot right now and the motor block felt really really hot.

Thx for your time!

perhaps th e ignition coils could be getting hot and malfunctioning. might check into this. my first gs i had would do this.  i rigged an old school chevy coil as a temp fix until got coils replaced

What makes me furious about this is that hack "tech" has charged $300 for nothing. What a complete ripoff! Ren, don't go there again if you can avoid it, or, on the other hand, get back in there and tell the pricks to FIX the problem, or you get your money back. If they don't help, please name them on this forum, and we'll spread the word on other forums. This is the only way we can 'out' ripoff merchants like this.
This isn't a diagnosis, but 'backfiring puffs' may be due to ignition problems, - at least as likely as carb problems. First step I'd try is to check every electrical plug in the ignition circuit, plug and unplug them a few times, check the connectors are nice and tight and without corrosion. (Could be your spark is dropping out intermittently due to a bad connection somewhere, causing unburnt mixture backfiring in the exhaust). I know the tell-tale signs are that it's stalling when hot, but check first things first. Does it stall when you let it go down to tickover or does it cut-out as you are going along? Change your fuse,  (not unknown for a fuse to break down when it gets hot, and it's a quick easy thing to do), check your wiring going to the ignition switch and the wiring going to the engine stop switch. (I recently got a $2000 bike for $500 because the owner didn't realise a simple wire to the ignition switch was broken!)
Check all earths wires to frame connections etc. Avoid starting to fiddle with carb screw adjustment screws yet... it can get you into more trouble If it's running perfectly well normally I wouldn't suspect carbs initially.
Hopefully there'll be plenty of help for you here. And maybe try to find a different DECENT mechanic to help.
Motors do get hot. And it does sound like a heat issue. One clue to an overheating problem would be if it stalls when/after you slow down or are in slow traffic, because (once it's up to temp), on a hot day the motor gets hotter when you stop or slow because it gets less cooling air.
Just a start mate. Hope you get it sorted easily.

Wow! Verry good advices! Thanks alot! I think im going to start by checking my sparkplugs then checking the fuses then try to change the ignition coils if it dosent work. I never suspected an electrical problem so the idiot mechanics scumbag at this shop.

Question: if its a fuse problem, why is the bike able to restart only after a 15-30 min cool down?

Also evry time it stalled it was either on a stop or while reducing speed

i honestly think its the coils getting hot. theres a specific way to test this. ill see if i can find it here

gstwins.com/gsboard/index.php?topic=19546.msg178960#msg178960

Your symptoms are actually pretty similar to when I hadn't checked my valves (ever) and they were way tight. When I pulled the clutch in to coast, or idle at a light, I was at risk of it stalling out and being hard to restart. If you haven't checked the valves recently, that might be a good thing to do, even if it isn't the culprit.

Quote from: Big Ren on September 17, 2015, 08:57:36 AM
Wow! Verry good advices! Thanks alot! I think im going to start by checking my sparkplugs then checking the fuses then try to change the ignition coils if it dosent work. I never suspected an electrical problem so the idiot mechanics scumbag at this shop.

Question: if its a fuse problem, why is the bike able to restart only after a 15-30 min cool down?

Also evry time it stalled it was either on a stop or while reducing speed

I'm certainly not saying this is your problem, but... A mate of mine wasted several months chasing a similar problem he had on his 05 VW Transporter. It turned out to be a simple blade fuse that when cool, tested continuity fine, but when it got hot a small crack opened up in the fuse-metal, (hidden by the plastic so you couldn't see the break) rendering it useless until it cooled. I'm sure this is a very rare problem, but a fuse costs 20c and is dead easy to replace so why not.