Hello everyone I believe my bike is having a fuel starving issue. Today I left the house and it having a problem that I think is fuel starving. The bike will stutter and then come back. It did die but I started in right back up. The big mystery is why. There was plenty of gas in the tank. I estimate about 1/4 tank. I got to the gas station and put about 2 gallons in and the problem stopped. But on the way home (less than 20 miles riding) the problem came back up! The fuel switch was set to the "on" position but it also does this in primary.

Any ideas?

It's actually PRIME not primary.  PRIME bypasses the need for vacuum to the petcock for fuel to flow, and also uses the reserve fuel line.  If setting to PRIME doesn't fix it, then your problem might be vapor lock due to a clogged tank vent.  To check, when the bike dies, open the fuel cap and listen for a "whoosh" of air.  There is a tutorial on how to clean the tank vent somewhere here as well.  Also make sure your carb vent is clear, and no tank bags.

+1

Also, if you have an in-line fuel filter, nix it. They are notorious for causing fuel issues on these bikes due to the gravity feed system. Another thing to note is that, due to the slope of the tank, it's really hard to properly estimate how much fuel is left (not knocking your estimation by any means). It'll collect in the bottom "pocket" and look like more.

Just out of curiosity, have you replaced the fuel lines recently, and are there any other notable symptoms like hard starts?

I haven't done much to the bike as far as replacing stuff. Its a 2008 and I'm the 2nd owner. The lines don't look new but they are still in good shape. The thing starts right up after a few turns and I don't even need to give it a ton of choke.

I will check what the last guy said then get back to you.

Ok I did a few things and the problem seems to be gone but I'm not sure if its actually fixed. I took apart the fuel cap to see if it was blocked, and it really wasn't even dirty at all. I also found that the hose that leads up to under the fuel cap was filled with water (left her out in the rain). I lifted up the gas tank as well as used compressed air and it seemed to had pushed a lot of water out.

I have only tested the bike extensively in the prime position and it works well. No stuttering, starving, etc. But when I first finished I tried the on position and it felt like it was stuttering a tiny bit. What else could this be?

edit: Also, would there be any problem just leaving the petcock on prime permanently? I would like to do highway riding and I hope it wont starve with that rate of fuel use.

If you're going to run it on prime (which will only mask, not fix, the issue), just be sure to turn it to ON when parked. Otherwise, it may leak fuel, depending on your float height (I believe?). It'll basically work like a dirt bike petcock at that point. Personally, I'd look for the permanent solution.

You'll need to replace the petcock.

Quote from: bombsquad83 on August 29, 2014, 07:32:00 AM
You'll need to replace the petcock.

You'll need to replace the petcock internals!
Just a small o-ring and a diaphragm are the only parts inside.
O-ring stops flow when NOT running, diaphragm makes it flow WHEN running.

Quote from: ace50 on August 29, 2014, 12:52:01 PM

Quote from: bombsquad83 on August 29, 2014, 07:32:00 AM
You'll need to replace the petcock.

You'll need to replace the petcock internals!
Just a small o-ring and a diaphragm are the only parts inside.
O-ring stops flow when NOT running, diaphragm makes it flow WHEN running.

That's true.  I think we've been through this... Do you know where to find the parts?  You can't find them through Suzuki OEM.

As far as o-ring, I use part # 2857T114   ($4.31 for pak of 5) from McMaster.com, They are Viton ETP Fluoroelastomer. I change them every year for that price.

If the diaphram as small holes or tear in it, try small amount of 'Seal-All' (Wal-Mart) on both sides and let it dry thoroughly.

the vacuum hose on the petcock could also be a key factor in this issue. check the hose to see if it is secured on the petcock and the vacuum system on the carburetor, as well as checking all the lines to make sure theyre in the right place. also if the inner lining of the fuel lines are coming off even the slightest, it could cause fuel starvation so be sure the fuel lines are in check. also, the vacuum lines are real cheap at autozone (like maybe a buck for the line?). If the vacuum line isnt soft and pliable, then toss it and replace it

Quote from: ace50 on August 30, 2014, 05:01:24 AM
As far as o-ring, I use part # 2857T114   ($4.31 for pak of 5) from McMaster.com, They are Viton ETP Fluoroelastomer. I change them every year for that price.

If the diaphram as small holes or tear in it, try small amount of 'Seal-All' (Wal-Mart) on both sides and let it dry thoroughly.

For what version of the petcock would that oring work?  There are 3 versions for different year ranges.  I believe '89-'00, '01-'02, and '04+.  I could be wrong on this.  Someone will be by to correct me.

Arent the petcocks interchangeable ? (If the need arises)

Arent the petcocks interchangeable ? (If the need arises)

Quote from: yamahonkawazuki on August 31, 2014, 09:01:53 PM
Arent the petcocks interchangeable ? (If the need arises)

You certainly could interchange them, but it might take some modification of the frame tab due to mounting hole differences.  The whole point of this discussion was to talk about how to repair the petcock you have so that you don't have to replace it.

Personally I replaced mine with a non-vacuum petcock, and I haven't given it too much more thought.

[quote author=JAS6377 link=topic=67856.msg816723#msg816723 date=1408843533
Just out of curiosity, have you replaced the fuel lines recently, and are there any other notable symptoms like hard starts?
[/quote]

Same problem here and it started immediately after I replaced two fuel lines.

Quote from: bombsquad83 on August 31, 2014, 07:09:42 PM

Quote from: ace50 on August 30, 2014, 05:01:24 AM
As far as o-ring, I use part # 2857T114   ($4.31 for pak of 5) from McMaster.com, They are Viton ETP Fluoroelastomer. I change them every year for that price.

If the diaphram as small holes or tear in it, try small amount of 'Seal-All' (Wal-Mart) on both sides and let it dry thoroughly.

For what version of the petcock would that oring work?  There are 3 versions for different year ranges.  I believe '89-'00, '01-'02, and '04+.  I could be wrong on this.  Someone will be by to correct me.

Mine's a 01. Can't say for others. I use this on my Kaw ZRX also.