Today I pulled into the gas station as the fuel tank supply truck was leaving.  I topped off the tank into the gas tank neck.  (Leaving on a 3200 mile ride shortly)  A minute later I am driving at 60 mph with the cruise control on and the bike feels like it is surging.  I have NEVER experienced this surging on the bike.

I ride about 4 miles home and as I pull through the gate the bike almost stalls.  It is running a bit rough and accelerating slowly.

My first inclination was that I got some bad gas.  When I opened the cap to siphon out the gas some of it blew out of the filler neck and onto the tank.  I siphoned it down below the filler neck and now it "seems" just fine.

I removed my CA cannister several years ago to make room for my Rostra.  My recollection was that I when I removed the cannister I looped the two lines together. 

My question is did I eliminate my vent by looping those lines together? Would lack of vent and overfilling cause what I experienced?

The answer seems to be yes and yes.  However, I am just a little wound as I am departing for a 3200 mile ride in about 5 days!

I can tell you that I almost always fill my bike into the neck and I've never had a problem. I do not have a CA bike, so it sounds like something that's different or changed about your bike (like eliminating the vent).

Which two lines did you loop together?  If the line leading from the tank to the canister is not open to the atmosphere, you indeed eliminated your vent.  Extend that line downward below your fairings.

Which two lines did you loop together?  If the line leading from the tank to the canister is not open to the atmosphere, you indeed eliminated your vent.  Extend that line downward below your fairings.

That would be the line

I read another post where someone just attached a mini automotive breather to this line and blocked the other one.  Any harm to just leaving the line open or should a breather be attached?

That would be the line

I read another post where someone just attached a mini automotive breather to this line and blocked the other one.  Any harm to just leaving the line open or should a breather be attached?

I believe the other one goes to the air box.  Block that one. Leave the one from the tank open. Preferably extend it so fuel and vapors clear your fairings but it isn't real critical.

What likely happened is that your tank burped fuel, it went in to the air box and temporarily flooded your engine.

I read another post where someone just attached a mini automotive breather to this line and blocked the other one.  Any harm to just leaving the line open or should a breather be attached?

That was me.  I removed the hose color coded red and capped the fitting at the tank. The hose color coded blue is the breather hose. I attached a cheep automotive fuel filter to that hose. I really don't think this it necessary and could probably just run the hose to the bottom of the bike.

Mark

That was me.  I removed the hose color coded red and capped the fitting at the tank. The hose color coded blue is the breather hose. I attached a cheep automotive fuel filter to that hose. I really don't think this it necessary and could probably just run the hose to the bottom of the bike.

Mark

I think I am going to just follow what you did and remove the separator and all lines.  However, I am going to wait until I come back from my ride aka leave well enough alone for now!

Thanks for the help

Interesting.

If you blocked the vent line to the tank your gas tank is likely to suddenly take on a new shape, picture a plastic bottle evacuated of all air!

If you blocked the vent line to the tank your gas tank is likely to suddenly take on a new shape, picture a plastic bottle evacuated of all air!

I don't think that would happen with a steel gas tank.  It would be more likely that the fuel pump would not be able to overcome the vacuum and then not be able to deliver enough gas and the engine would go very lean and then stop running.

I don't think that would happen with a steel gas tank.  It would be more likely that the fuel pump would not be able to overcome the vacuum and then not be able to deliver enough gas and the engine would go very lean and then stop running.

Trust me, it can. I had it happen on a Ducati after a dealership mechanic pinched the return line during a service and didn't catch it. It was sudden and very loud.

Trust me, it can. I had it happen on a Ducati after a dealership mechanic pinched the return line during a service and didn't catch it. It was sudden and very loud.

Wow!  I just would not have believed the fuel pump could be that powerful and all the seals that strong!

Yep, the top of the tank buckled down about 2 inches. I was riding and heard a loud pop. Stopped and didn't see anything right off, but headed to the house. When I got home and picked up my tankbag, holy s&$t! It looked like someone took a swing at my tank with a sledgehammer. Dealer didn't argue since it was about 3 days after the 600 mile service, but it did take a few weeks to get a new tank from Italy.

Yes, the gas tanks can "implode".  There were a few pics on our old site that showed this was a very real occurence.

Yep, the top of the tank buckled down about 2 inches. I was riding and heard a loud pop. Stopped and didn't see anything right off, but headed to the house. When I got home and picked up my tankbag, holy s&$t! It looked like someone took a swing at my tank with a sledgehammer. Dealer didn't argue since it was about 3 days after the 600 mile service, but it did take a few weeks to get a new tank from Italy.

What you SHOULD have done is saved that old tank, and sold it over Craigslist as a "pro stunna tank."  Pro stunnas deliberately bash the top of the tank to turn it in to a seat, for high chair wheelies.

Wow!  I just would not have believed the fuel pump could be that powerful and all the seals that strong!

Happened to my buddy while riding his GS-1150.  We pulled into a gas station for fuel, and it looked like someone bashed in the side with their helmet.  He found the vent line was plugged with dirt/grime/etc.

Tank internal electric fuel pumps really suck. 

Happened to my buddy while riding his GS-1150.  We pulled into a gas station for fuel, and it looked like someone bashed in the side with their helmet.  He found the vent line was plugged with dirt/grime/etc.

Tank internal electric fuel pumps really suck. 

I am not sure in that case it would matter if the pump were inside or outside the tank.

I am not sure in that case it would matter if the pump were inside or outside the tank.

Actually it can, if a rubber hose is between the pump and the tank.  A rubber hose can collapse from the suction, effectively sealing off the tank from the pump.  This depends on the quality / structural rigidity of the pump inlet hose though too.