2008 GS500F works in Prime, but slowly dies in ON and Reserve Positions

[86Cutty]

My bike runs fine in the Prime position, but when I have it in the ON or Reserve Positions the RPMs slowly get lower until it finally just cuts out. Then when I try to start it again in the ON or reserve positions it starts, then cuts out immediately. I was looking around on here and I saw that some people were having issues with fuel starvation and the petcock, but I'm not sure if that's the same issue I have. I know the tank is full, but my bike just wont stay on in those two positions. Also, when my bike is first put in the ON position and the RPM's start to get low (1000ish rpms) I noticed a (not really a pop noise) more like a click noise every now and again. (It's close to the idol adjustment screw). I'm still new to riding so I don't really know much about bikes.

Has anyone else had issues like this, or are there any trouble shooting techniques I can try to figure out what could be the cause? I really want to get my first bike back to normal. Any advice would be appreciated.

Thank you for your help.

[Funderb]

3.... 2.... 1.... adidasguy:   


Check these things before deciding what other options to do: (aka replacement)
vacuum hose from carbs to pcock
-look for cracks, or missing-ness

Pcock diaphragm
-if its been sitting a long time, it may mave dried out and cracked or become too hard to work correctly.

Both can be replaced cheaply and easily, and the system will work fine for years.

if you dont like that, you can replace it! (with a totally new system - just do a little search for petcock delete) but theres no real reason to do so.

[86Cutty]

3.... 2.... 1.... adidasguy:   


Check these things before deciding what other options to do: (aka replacement)
vacuum hose from carbs to pcock
-look for cracks, or missing-ness

Pcock diaphragm
-if its been sitting a long time, it may mave dried out and cracked or become too hard to work correctly.

Both can be replaced cheaply and easily, and the system will work fine for years.

if you dont like that, you can replace it! (with a totally new system - just do a little search for petcock delete) but theres no real reason to do so.

Thank you for a quick reply.
What do you mean by "Missing-ness"? Like the whole vacuum hose is gone, or do you mean something that attaches to the vacuum hose might be gone?

[adidasguy]

I'm here. Was out for a while.

Yes - vacuum line to petcock has a leak. On a 2008, the vacuum line comes from the right carb. There is a T for it and the vacuum line continues elsewhere.

Most likely since it is getting some fuel, it is one end of that line is off. Or there is a crack or hole in the line. Being a 2008, most likely something got pulled off when the bike was worked on last time. Hose diagrams are available if you need one.

People with petcock problems:
1. They are most often old bikes with old, work out petcocks.
2. They are VERY vocal proclaiming to the world that a vacuum petcock is crap. They're not. Tons of bikes have them and few of us have any problems unless it is an old, work out one or there is a vacuum leak.

[SS Adrenaline]

Well said as always adidas.

[86Cutty]

I'm here. Was out for a while.

Yes - vacuum line to petcock has a leak. On a 2008, the vacuum line comes from the right carb. There is a T for it and the vacuum line continues elsewhere.

Most likely since it is getting some fuel, it is one end of that line is off. Or there is a crack or hole in the line. Being a 2008, most likely something got pulled off when the bike was worked on last time. Hose diagrams are available if you need one.

People with petcock problems:
1. They are most often old bikes with old, work out petcocks.
2. They are VERY vocal proclaiming to the world that a vacuum petcock is crap. They're not. Tons of bikes have them and few of us have any problems unless it is an old, work out one or there is a vacuum leak.

Well, I was looking at the hoses on the bike before removing the tank, and I have a couple of questions:

http://s569.photobucket.com/albums/ss134/86_Cutty/

(That link goes to the pictures I just took of the hoses I'm wondering about)
What do these hoses go to, and should they be sitting like they are?

I haven't taken the tank off yet because I don't know how, and I don't want to mess anything up. So I figured I'd ask before digging a hole for myself.

[adidasguy]

One looks like the airbox drain hose came off.
The thingy with the yellow foam is a breather filter and is OK.
Can't see what else you're wondering about. Maybe point to it with a pencil? Or add a circle to the photo indicating your concern.

[86Cutty]

One looks like the airbox drain hose came off.
The thingy with the yellow foam is a breather filter and is OK.
Can't see what else you're wondering about. Maybe point to it with a pencil? Or add a circle to the photo indicating your concern.

So I should reconnect the airbox drain, and leave the foam inside it? I'll leave the yellow foamed hose alone. I guess that's all I was wondering about with those pictures. I took the tank most of the way off, but it's full of gas so it got heavy. All the hoses looked ok minus the fact that they were turning gray. I managed to turn the screw under the gas tank to the off position and take 3 more pictures before putting the tank back on the bike. (They're at the same link as above, but they weren't really great pictures, sorry). I was worried all the gas would dump out of the third hose under the tank or of messing something up.

I was going to try to disconnect one of the hoses to see if any of them were clogged, but they're on there pretty tight. I think I may be a bit over my head because I don't know what I'm doing.

[adidasguy]

By your pictures it appears the airbox drain is off. That is just a drain down to the lower right side where the battery drain is.
The yellow thing is a breather and the open end goes nowhere.

FYI: The hoses ARE gray! 

The 3rd hose under the tank is the drain around the gas cap. It can be disconnected when the tank is off. It ends up lower right with the airbox drain hose.

In this photo, you see a "T" with a red cap. IGNORE THAT "T"! You will not have a T there. (The T is connected to emissions for California models - it is a CA model here and I removed the emissions in the process of dismantling the bike.)
That particular hose is the vacuum line to the petcock.

[86Cutty]

By your pictures it appears the airbox drain is off. That is just a drain down to the lower right side where the battery drain is.
The yellow thing is a breather and the open end goes nowhere.

FYI: The hoses ARE gray! 

The 3rd hose under the tank is the drain around the gas cap. It can be disconnected when the tank is off. It ends up lower right with the airbox drain hose.

In this photo, you see a "T" with a red cap. IGNORE THAT "T"! You will not have a T there. (The T is connected to emissions for California models - it is a CA model here and I removed the emissions in the process of dismantling the bike.)
That particular hose is the vacuum line to the petcock.

Is the line you were talking about that I have in red, and the circles are the "T's". Is this the vacuum line?

[adidasguy]

That's the line.

Where does the line go that's going towards the front of the bike? I can't recall anything up there that it connects to. If it is open - cap it off. Problem will be solved.

UPDATE: OK, it is supposed to go to the PAIR system at the front left. Mine went nowhere because I'm removing the PAIR system.

I recall the capped off line went to emissions which I removed.
Be sure there are no open ends on that one. Possible your petcock is bad. Or the vacuum line to it is pinched.
You can unscrew it from the frame.
If you attach a clean hose to the vacuum line you can suck it and hear the diaphragm open and close like an artificial heart. A new one shouldn't go bad. My guess is a disconnected line somewhere or the vacuum line to it is pinched between the frame and the air box.
If it was connected to the tank or other gas source, you could suck the vacuum line and see gas come out of the line that goes to the carbs. Using just air, blow into the main or reserve input gently. With a syringe or turkey baster such on the vacuum line. With that vacuum, it should open the diaphragm letting you easily blow through it depending on the position of the knob and which you are blowing through.  If you turn it to PRIME, you will be able to blow air through it without any vacuum.

ADDED DIAGRAMS

[86Cutty]

Sorry, I was gone for a few days. I'm not that great at diagrams, but is it ok to just ride my bike for a few days like it is? My mechanic is gone til Sunday, and I'd feel more comfortable if he looks at all this since he would know what he's doing, and I don't. lol I also noticed that I have a small oil leak. I may just have him check on what you said about the vacuum leak and the petcock, and also fix the oil leak. If I were to work on it myself I'd have to get you on Skype or something so you could see what I see, and direct me that way.

[adidasguy]

You can run on PRIME. Remember you have no reserve so keep the tank full.
Put back to ON or RESERVE when not running the bike so you don't accidentally flood the carbs.

[mister]

Out of curiosity, where is this oil leak you think you have?

Michael

[86Cutty]

It's leaking from the bottom nut you take off first when you change the oil. I noticed some oil on my bike cover after leaving the bike sitting for about 7 days.



I started up the bike, and after getting it idling ok I turned it off and noticed smoke was coming out of the tailpipe.



It kinda smells like...IDK. Oily gas, or maybe old gas. I know it's not old gas because I filled it up after the tank was empty (I think it was because the Petcock was on Prime all this time) and I filled it up a few times after that. Also, when the weather started getting warmer, I drained all the gas I had in it from the little screw you can unscrew to get the gas out without taking the tank off (thats what the mechanic said anyways) I don't think I'll ride it around until my mechanic can take a look at it. It seems like there's more going on than just the vacuum/petcock issue. 

[somi79]

 Please let me know what you figure out with the fuel problem. I'm having the same issue on a '07 gs500f. It ran fine for a couple of weeks, and than one day it just decided to stall out on me. Problem ever since. I need to get back to riding! Thank you in advance.

[adidasguy]

Does it run OK on PRIME?
If not, does it run OK with the gas cap open (in case the microscopic vent hole in the cap is plugged up)?
Do you have an in-line fuel filter? If so, try without it.

Remember that PRIME is free flowing straight through the petcock. if there is a problem that way, it is not the petcock. Its somewhere else.

Inside the tank: What about the in-tank screen filter? Is it clogged with debris?
Do you have an air leak somewhere?
Bad gas? (and I don't mean from eating garlic & beans)

[somi79]

 No in-line filter and gas cap has been taken apart and cleaned. Not sure how well it runs on prime for extended periods of time, only tried it out for a few minutes. I took the tank off and inspected all the hoses.  The vacuum had a kink in it towards the front of the bike where it connects to the PAIR valve, but removing it did not seem to fix the problem. Removed the petcock yesterday and disassembled and cleaned it.  Bike starts and idles on the on position until it warms up.  I then take it out on a ride and a few minutes later it stalls out.  The only way I was able to restart it and ride it home was on the prime position. Thanks for your speedy reply. Much appreciated.

[somi79]

 I guess my next step is to check the in-tank filter.

[86Cutty]

Well, we found out what the issue ended up being. It was the filter that's in the tank. I had my bike sitting at a friends garage to stay out of the rain and snow. I guess he decided  to saw wood, and he didn't think to cover the bike till he was done sawing. Some saw dust ended up getting in the tank and it stopped up the filter. The fuel filter that came on the bike was completely clogged. After the mechanic cleaned it out it ran fine. The oil leak is the next thing to get fixed, and the plugs because they were a wee bit old looking. Now there's no more smoke coming out of the tail pipe, and there was nothing wrong with the petcock. It's working great. No adjustments, or rigging up, or anything like that. I guess the issue was just plain ignorance in my part.  Thank you adidasguy for help in diagnosing, and the schematics on the hoses. It was actually used and it looks more organized under the tank.  After the Oil Filter, Oil, and Plugs changed I'll have her on the road again.