Bike Won't Run - Starts, But Sputters and Dies

[Turkey]

Hi Everyone,

I recently (May 2017) became the owner of a 2007 GS500F with only 5000 miles. I was riding it a couple weeks ago, enjoying some nice weather and a spectacular sunset when I noticed my idle starting to slow down. The bike seemed to be running fine at higher RPM, but every stop the idle started getting slower and slower. Eventually, the bike died when I was at a stoplight. At this point it wasn't starting unless I gave it gas, and would chug at 800rpm for a few seconds before dying. It eventually started to leak fuel (I think I flooded the engine), and I ended up having to push it a mile and a half home. Because the bike was turning over, I don't think it's a battery problem.

Since then I've been trying to get it to start. I cleaned the carbs (guitar string + carb cleaner on the jets), drained the fuel tank and replaced it with fresh gas (I noticed there was some debris in the gas tank), and replaced both of my spark plugs (the old ones looked really black, so it seemed like fuel was definitely getting the engine but it could have also been from my overuse of choke to warm up the bike on colder days). The spark plugs prior to replacement both had a spark, but I replaced them for good measure. The problem persists. Even with the choke all the way open, the bike will momentarily start, idle at low rpm (<800rpm), and then die. If I give it gas during the short period it runs, it does rev up, but it sounds abnormal, what I might describe as "thin" or "weak." There seems to be no difference in starting if I use Fuel, Prime, or Reserve on the Petcock.

If anyone has an idea of what might be wrong, the advice would be greatly appreciated. I'm just about ready to bring it to a shop, but that would require me pushing the bike a couple miles.

[ajensen]

The shop is the last resort. You can fix the problem. The first step is to make sure the carbs are working correctly. I am an old-time mechanic and am very fond of doing things that seem crude to the young guys. One thing I would do is pull the air box out and crank up the engine. Be sure to have a fire extinguisher close by. As the engine runs, try putting your hands little by little over the carburetor mouths. If it runs better, it is too lean. If it runs worse, it is too rich. Remember to wash your hands thoroughly to get the gasoline off. I am sure the rest of the members can give you more intelligent advice, but sometimes the  most basic troubleshooting can help. I am curious about what others say and what ends up being wrong with your bike. BTW you can gain great satisfaction as well as save a bunch of money by fixing things yourself. Keep us posted.

[Big Rich]

I'm going to say your carbs need cleaned properly. A guitar string thru the jets gets about....... 10% of your carbs clean. All of those passageways the string can't get to can still be clogged.

Have access to an air compressor? Or can you boil the carbs (hint: NOT INSIDE YOUR HOUSE!).

[Watcher]

How's your air filter?

[Bluesmudge]

You say it started to leak fuel. Where was the fuel coming out?
If you take out the oil dipstick and smell in there, does the oil smell like gasoline?

[HPP8140]

how many miles on the bike now?

[Big Rich]

how many miles on the bike now?

5000 miles.

[Watcher]

how many miles on the bike now?

5000 miles.

Literally in the first sentence, lol.

[Big Rich]

Meh. Easy to read everything else and forget it.

So Mr Turkey......whats the word?

[J_Walker]

Meh. Easy to read everything else and forget it.

So Mr Turkey......whats the word?

[Kookas]

Had the same issue. Needed new float valves.

[HPP8140]

how many miles on the bike now?

5000 miles.

Literally in the first sentence, lol.

That was in May, it's now October

[Turkey]

The bike is now at 5500 miles since I've gotten it.

[Turkey]

You say it started to leak fuel. Where was the fuel coming out?
If you take out the oil dipstick and smell in there, does the oil smell like gasoline?

It was hard to definitively pinpoint, but it seemed it was leaking out of a dangling hose that was capped (An overflow hose? It may not have been leaking from here but just running down and dripping on the hose). It was pretty dark out when it was leaking so I didn't get a great look, but it hasn't leaked since.

[Turkey]

How's your air filter?

The air filter is a little dirty, but nothing significant.

[Turkey]

Meh. Easy to read everything else and forget it.

So Mr Turkey......whats the word?

Sorry for the delay in response. I unfortunately haven't gotten a chance to work on the bike much. I'm hoping that I can try a couple of the suggestions (boiling the carbs, check the float valves, etc.) this week. It has gotten fairly cold out so I was hoping a warm day might pop up and I could work on the bike a bit without my fingers going numb, but that may be wishful thinking now that November is right around the corner.

[Turkey]

I'm going to say your carbs need cleaned properly. A guitar string thru the jets gets about....... 10% of your carbs clean. All of those passageways the string can't get to can still be clogged.

Have access to an air compressor? Or can you boil the carbs (hint: NOT INSIDE YOUR HOUSE!).

The carb cleaning I've done thus far has only been soaking/wiping the bowls with carb cleaner and running carb cleaner and string through the jets. I noticed some debris in my gas tank, and thought maybe some of that worked its way into a jet, but all of the jets at least appeared clean pre and post cleaning. The carbs look fairly clean, but I might give the boiling thing a shot to be sure. Thanks for the suggestion.