Is your '08 carbed or an EFI? On my '02, a short hose runs from the petcock to the 'fuel rail' down low, running between the carbs, but this may not help if yours is an EFI.

You mention a hole in the bottom of the petcock, I see the locking screw that holds the assembly together is in place, so there's no 'hole' other than the petcock 'feeder' pipe. There's also a tank breather hose nipple the right side of the tank which should be connected and daylight down in front of the swing arm.

 

There is only one hose connected to the petcock as @LapinAgile says. Any extra hose hanging in that area may be leftover from the AI removal. if the fuel is coming from an overflow tube your bike might have sat too long and developed carb crud and now needs cleaning.

 

Thanks @LapinAgile and @rweb.

I finally got it started last night. It would idle for a bit then die. After about 30 minutes of this with my neighbor's standing around drinking beer and offering "suggestions" it idled continuously, but would die when I cranked the throttle. After letting it idle for another 10 minutes or so, it throttled. I drove it down the street and back at 5 MPH and put it back in the garage.

This morning it was draining fuel out of the mystery hose and the black plastic horn shaped device below the fuse box. Hopefully this is just after effects of the carb crud. I will look for the tank breather hose nipple the right side of the tank, and or any other place the mystery hose may go.

Thanks again for the insight.

 

Can you post a pic of the 'horn shaped device' below the fuse box? I can't imagine what that may be. Did you return home at 5mph by choice or was that the result of misfiring?

There are potentially only three hoses, one from the tank to the petcock, one from the tank right side to daylight below the bike, and one from the carb breather nipple down to daylight. This breather hose is optional, I deleted it long ago with no ill effects. Once you're confident you've got the hoses sorted, run a bottle of SeaFoam through the tank with some aggressive riding, it should help the crud issue.

Read the stickies here in 'Tech Talk' regarding rough running etc, and look for some photo examples of carbs and their hose placement.

Good Luck!

 

@LapinAgile - Yesterday on my 5 MPH ride I just put it away after a short ride because I didn't want it to stall and have to push it back up the hill to my house. I ID'd the 3 hoses as you stated below. Gas is coming out of the carb to daylight hose when I turn the petcock valve to on and try to start.

Today, it won't start. When I crank it dirty fuel comes out of the hose from the carb connectors and from the horn? Why would fuel spill from the horn? If that is the horn.

I put some more new gas and sea-foam in the tank and hopefully it will turn over in a while. This will teach me to ride my dang bike more often.

Just cranks today. Won't catch.

I'll check the stickies. Thanks.

Here's a pic of where the fuel is spilling out.

 

That is not the horn, it's the air box snorkel. Pinch it in on one side ware it inters the air box and twist and pull it out if you want. As I mentioned earlier your carbs need cleaning. When you have gas leaking from anywhere when the fuel tap is on and there are no loos or damaged hoses or ''O'' rings it's most likely leaking past the carb needles and overflowing the carbs and needs cleaning. The fact that the engine won't rev also indicates clogged jets.

 

Thanks! I'm learning.

 

Yes, there's gas leaking into the airbox from blocked carbs. You can just loose the snorkel if you like, but the airbox must be cleaned out and likely the air filter will need replacing due to the gas soak.

Here's a vid of removing the gas tank:

It's much easier to get to the carbs, and you'll see where the tank overflow hose should hook in. Drop the bottom carb bowls, spray carb cleaner and wipe clean. Remove the carb top screws carefully there's a spring below them, carefully remove all parts noting how they were removed - no panic, very easy basic stuff. Spray all thoroughly to clean. Removing the jets would be good too for a complete job, check here for pics. Install hoses correctly, reassemble tank and you'll be riding a Bonneville shortly!

NewBonneville sells a great kit for the carb top/bottom bolts, much easier, the originals are 'not quite' allens and will strip easily if you're not careful.

A day's work, easy stuff - Good Luck!

 

The Youtube above is good but keep in mind that the OP's bike is a carbureted model so obviously there'll be no fuel pump, or electrical connection to one, in the tank Personally I don't drain my tank when I remove it although if the tank is full of gas it does get pretty heavy.

The advice on the carb screws is excellent too. The originals are soft and easily stripped. They're also JIS, which is not quite Philips and easily buggered up with a Philips screwdriver. The kit from NewBonneville ( https://newbonneville.com/shop/carburetor-screw-kit/ ) is well worth the $6.

 

If the carb screws haven't already been too badly buggered get a new #2 Phillups screw driver tip like you would use in a drill. Push it into the screw with one finger and turn it with a 1/4'' or 5/16'' wrench, depending on the tip hex. Once broken loos use the Phillups bit to remove and start screws. Much easier than a bulky screw driver in the space available. On good unmolested screws these things fit and work really well.

 

I had to go out of town for a couple of weeks for work. When I returned I cleaned the carbs, installed the new hex screws, and was able to get it started. I put some new gas in and a bit of SeaFoam, now it will run okay for a few minutes, then when when i give it gas it will not rev, and it pops a bit (not quite a backfire, then stalls. Back to to doing more research. :/


My world:
1. Start it up, let it idle and warm up.
2. Ride it for a bit around the block - had it up to 50 MPH.
3. Park in driveway and let it idle (idles rough and low).
4. Try to rev the throttle - no increase in RPMs, eventually dies. If I attempt to ride in this state, it will not go over 10 MPH, even with the throttle maxed.
5. Restart, idles rough and low then dies.

 

Did you ever solve this?
Since it sat for a while, could there be rust or gunk in the fuel tank that's going down into the carbs?