V11 Vapor Lock or Something Worse?

[guzzidog11]

I just realized I posted this in the wrong forum. I'll try it here. My apologies to the banter and silly stuff people.

 

I have started to have an unpleasant problem with my 2001 v11 Sport. I have always had the issue with vapor lock on hot days. After shutting down the engine on a hot day the bike won't run again until it cools off. In the past couple of days I have started to have the engine quit while running. I use the bike mainly for commuting 11 miles each way back and forth to work. In the mornings it works perfectly. Going home in the late afternoon in 80 degree weather the engine starves and dies after about six miles--it has happened on the last two consecutive rides home from work. This is a major pain and makes for a long ride home...

 

Last night after stalling I waited until the engine cooled a bit (30 minutes later) and it ran for about a half a mile and died again. A friendly motorcyclist/homeowner on my route offered his garden hose to cool down the engine and I was able to drive the remaining four miles to my home without a problem. I think the problem is fuel line related. The fuel pump sounds like it is working fine and when cool the bike is running as well as she ever has. I ride year round and had no problems this past winter. I have wrapped the main fuel line with some insulating foil tape to try to keep the fuel line cooler, but this hasn't helped.

 

Has anyone experienced this or have any suggestions for a remedy?

 

Thanks in advance,

John

[Guest ratchethack]

John, from your post, it isn't clear if it's quitting while underway, or simply dropping out at idle at a stoplight and refusing to start.

 

Please clarify.

[guzzidog11]

John, from your post, it isn't clear if it's quitting while underway, or simply dropping out at idle at a stoplight and refusing to start.

 

Please clarify.

Ratchethack-

Oops, sorry about not being more specific. The bike is choking off and quitting while underway--last night it happened in mid stride at about 40 mph. It coughs a few times and then stops. It is just like running out of gas--something I have experienced before . One other fuel line clarification: I removed all of the extra emission plumbing to fix the tank suck problem when the bike was new eight years ago. I appreciate any advice you may have. You were most helpful with a speedo problem I had a few years back.

[Greg Field]

SOunds like a bad petcock or a venting issue. Do you still have the electric petcock? If so, replace it with a manual petcock. Leave the manual one open all the time unless removing the tank. While you are in there, re-route or shield hoses to reduce the tendency to vapor-lock.

[Guest ratchethack]

Ratchethack-

Oops, sorry about not being more specific. The bike is choking off and quitting while underway--last night it happened in mid stride at about 40 mph. It coughs a few times and then stops. It is just like running out of gas--something I have experienced before . One other fuel line clarification: I removed all of the extra emission plumbing to fix the tank suck problem when the bike was new eight years ago. I appreciate any advice you may have. You were most helpful with a speedo problem I had a few years back.

John, sorry if you've got this covered, but are you sure you solved the tank suck problem? If you open the fuel filler after it chokes off and quits underway, you should NOT hear a rush of air going in -- unless you've still got a vent blockage.

[guzzidog11]

Thanks for the replies.

 

I don't think it is a venting problem, because I don't hear a rush of air when I open the filler cap. I haven't had the rush of air or the compressed gas tank problem since I removed the extra plumbing.

 

As for the pet cock issue, how do I tell if I have the electric one? I have the grey valve on the bottom of the right side of the tank with what appears to be a little vent on the bottom that swivels and I have the silver valve that hooks to my main gas line on the left side. The silver valve has wires attached, but they have been disconnected for many years. I am guessing the silver valve is the pet cock??

 

I did have the tank off recently as I was trying (unsuccessfully) to fix an oil leak on the top of my transmission. I might have reconnected some things incorrectly...

 

Any thoughts?

John

[Guest ratchethack]

John, the silver valve you've noted on the left-hand side of the tank is the electric petcock. It needs a live electric feed to open. It appears that somehow you've been riding around disconnected, and therefore it should be closed. (??) It may have been stuck in the open position and got bumped around enough to close up when you had the tank off. I'd test it and if defective, clean, fix, or replace with either another or a manual one. There's only one way those connectors can go back together.

 

Good luck.

[guzzidog11]

John, the silver valve you've noted on the left-hand side of the tank is the electric petcock. It needs a live electric feed to open. It appears that somehow you've been riding around disconnected, and therefore it should be closed. (??) It may have been stuck in the open position and got bumped around enough to close up when you had the tank off. I'd test it and if defective, clean, fix, or replace with either another or a manual one. There's only one way those connectors can go back together.

 

Good luck.

Great. I'll focus on fixing the pet cock issue and get back to riding.

 

Thanks very much for your help.

John

[Guest ratchethack]

Por nada, mi compadre.

 

FWIW, this may or may not apply in your case, but one of the ways the electric petcock typically goes South has been setting the tank on a flat surface, which actually cuts into the wires with the sharp end of the petcock housing, wreaking havoc on the fragile wires, and creating a common source of fueling problems.

[raz]

FWIW & IIRC, we had a thread here a year ago or so, where a non-working electrical petcock was confirmed being sucked open by the fuel pump. Surely not without ill effects, but it ran.

 

Or was it a theory that was later abandoned? I'm not 100% sure. I'll try searching for it later.

 

Edit: It was ALdad and Velf2003, in this thread.

Hi all,

 

I too suffered from this problem. It is true that the pump will suck open the fuel petcock even is it isn`t powered by a broken wire on a electric petcock. The sound the pump will give then isn`t the normal sound but higher, asmatic. The hotter the temperature of the air, and therefore the engine, the worse the engine will run and finally it will stall.

 

Took some 45 minutes to let it cool down and start all over again to warm up when it would restart.

 

I solved the problem by resoldering the broken wire back on. It now survived 30.000 km....

 

 

Good luck!!

 

Velf2003

[Indiana Chuck]

FWIW & IIRC, we had a thread here a year ago or so, where a non-working electrical petcock was confirmed being sucked open by the fuel pump. Surely not without ill effects, but it ran.

 

Or was it a theory that was later abandoned? I'm not 100% sure. I'll try searching for it later.

 

Edit: It was ALdad and Velf2003, in this thread.

 

yep, they'll do that. I haven't tried this for insulation, but I'll bet it will work. Used on aircraft for years.. http://www.aircraftspruce.com/catalog/appages/stratofs.php

[guzzidog11]

Thanks to everybody who responded. Guzzi people rock I am planning to tear into the petcock this weekend and determine why/where it is malfunctioning. I hate to have to take the tank off again, but so be it. I will start with making sure the wiring is where it should be. Then I will make sure the venting is right.

 

Thanks again everyone!

John

[guzzidog11]

So, to hopefully finish the story, I took the tank off to check the ventilation and rewired the electric petcock this weekend. I think I mentioned that the petcock had been disconnected or the wires had pulled out of their connector a few years back. After rewiring the petcock, I decided to see if I could make it stall on me. I rode about 30 miles (aggressively) with no problems at all. Even though it wasn't quite as hot outside as when I had my earlier problems (60 degrees F rather than 80 degrees F), I think I have this problem solved.

 

Thanks to all of you who gave valuable advice. I am thinking I will order the non-electrical petcock and replace it anyway to avoid any future problems. It sounds like the right thing to do.

 

Thanks again. You guys rock!

[neville briggs]

Had the same problem with my V11 in hot weather. This is how I fixed it. Pulled the tank off after carefully disconnecting all the wireing.Losened off the external fuel pump and slid it through the clamp to give a little more freeplay to the fuel line. Disconnected the pet cock fuel line and rerouted away from the left cylinder barrel cooling fins which it was touching. I wrapped a heat resistant sticky backed silver foil tape like is used on exhaust down pipes around the fuel pump and fuel line from the pet cock. After rerouting I managed a gap of around 30mm from the cooling fins to the side of the fuel line. This gap plus the tape has stopped the fuel pump from cavitating due to the petrol in the line boiling to gas under the vacum caused by the pump. Hope this has helped. NB

[ScottS]

Had the same problem with my V11 in hot weather. This is how I fixed it. Pulled the tank off after carefully disconnecting all the wireing.Losened off the external fuel pump and slid it through the clamp to give a little more freeplay to the fuel line. Disconnected the pet cock fuel line and rerouted away from the left cylinder barrel cooling fins which it was touching. I wrapped a heat resistant sticky backed silver foil tape like is used on exhaust down pipes around the fuel pump and fuel line from the pet cock. After rerouting I managed a gap of around 30mm from the cooling fins to the side of the fuel line. This gap plus the tape has stopped the fuel pump from cavitating due to the petrol in the line boiling to gas under the vacum caused by the pump. Hope this has helped. NB

 

have a new to me 2000 V11, and I am having similar problems- after shutting down ,the engine heat soaks and it may or may not start , and if it does start it seems to run out of fuel after a few seconds. ( it has been 90+ degrees F lately) Letting the engine cool about 45 minutes is required before it will start and stay running.

 

I would never have considered the electric petcock could be non-functional but still sucked open by the pump- until I read it here - and I assume the theory is that cavitation in the pump due to boiling fuel in the lines prevents the malfunctioning petcock from being opened by the pump ? So both problems need to be solved- manual petcock and relocated/insulated lines.

 

Anyone ever take pictures of the prefered line routing ? Can the elecric petcock be modified in some way to stay open ?

 

May thanks for this forum ( my first post with words) I finally have the bike i have lusted for after 9 years ( 2000 V11 Sport) and initial feelings are that I am going to be very very VERY happy.