V1100 sport Vapor lock

[nsmith]

2000 V1100 sport runs like a dream, almost perfect, funest Guzzi I have EXEPT. After I shut it off and it sets a while it will heat up the fuel system until the fuel boils and now I'm stuck wherever I am for another 45 minuets. the fuel pump and filter are external. Does anyone know the cure for this, I'm willing to really fix this but I can't find anyone who claims to have a for sure fix and I don't want to chase this round and round. Some previous owner made a heat shield for the fuel pump but that didn't fix the problem. I placed a plumbers cloth heat shield between the Left cylinder and the fuel lines and that didn't work either. So if you know what has been proven to work please educate me some.

[Rebochi]

2000 V1100 sport runs like a dream, almost perfect, funest Guzzi I have EXEPT. After I shut it off and it sets a while it will heat up the fuel system until the fuel boils and now I'm stuck wherever I am for another 45 minuets. the fuel pump and filter are external. Does anyone know the cure for this, I'm willing to really fix this but I can't find anyone who claims to have a for sure fix and I don't want to chase this round and round. Some previous owner made a heat shield for the fuel pump but that didn't fix the problem. I placed a plumbers cloth heat shield between the Left cylinder and the fuel lines and that didn't work either. So if you know what has been proven to work please educate me some.

     

  On my 1100 sport I moved the fuel pump forward away from the exhaust and wrapped it exhaust insulation . That helped some but did not cure the fuel boiling. My next plan was to eliminate the air box and move the fuel pump into that space.  I sold it and it became someone else's problem and bought a 2003 with the fuel pump in the tank.

[nsmith]

thanks for the reply but it doesn't answer my question. It does however tell me something that did NOT work. So again thank you.

[FarmallA]

nsmith,
I have a 97 (yellow) 1100 Sporti. Mine doesn’t seem to have the problem you describe, but I can’t understand how the fuel could boil when it’s being circulated from and back to a cold tank at a pretty high rate and pressure (well, 45psi anyway).

Be that as it may:
Are the fuel lines where they pass by the front exhaust pipes the thick braided stainless ones?

Is the fuel filter clogged?  It’s not expensive or hard to replace.

Is the fuel petcock on the left side of the tank open all the way?, and is the fine plastic screen inside the tank (part of the petcock)
not clogged with fine rust silt?  Either one could make a low pressure situation before the pump. Could that boil the fuel?

Actually, the first longer ride I took on mine, it acted like it ran out of fuel after 50 miles. Turns out the bottom half of that screen was clogged solid. Requires draining the tank.  And be careful with removing/replacing it.  The nut is an odd half left-half right thread, and it’s aluminum, easy to strip. 

Good hunting.
FarmallA
Steve

[Tom]

Move the fuel pump with longer hoses towards the rear of the bike.  Reroute it towards the fender. You could also insulate the pump.  I used a section of inner tube.  Good luck.

[Mr Revhead]

Have a look here:

https://www.v11lemans.com/forums/topic/462-vapor-lock-and-tank-suck-faq/

[Turin]

Injected 1100 sports, Daytona's and Centauro's do not have this issue. (even in the arizona heat)
I think it's an issue with the pumps location. As said before, lot's of info on V11lemans.com

[janguzzi]

I got this tip from a good (former) Guzzi mechanic.

Check whether the pump and filter have been swapped (this has happened on some motorcycles!).
The pump must be at the top of the frame; behind the oil cooler, the gasoline in the pump boils and the pump can no longer push fuel through the filter.

You can see this on page 68 here:
https://www.guzzitek.org/gb/ma_us_uk/1100/V11_1999-2003_Atelier(Compil-GB-D-NL).pdf

[LowRyter]

Does opening the gas cap help?