Fuel starvation

Laverda1000.de

Laverda1000.de

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Haßberge, Germany
Sorry Rob, I was in too much of a hurry to phrase this correctly. Stupid to assume people know about my triple woes. So here is the edited version:

I finally got around to swapping carbs and tanks between the 73 and the 74 triples. The 73 had started losing power at around 2800rpm after a short time of riding. After idling for a minute it ran alright for a minute, then same. Opening the filler cap didn't help. I suspected fuel starvation. Swapped over the tank and carbs from the 74. Bike ran like a treat. So fuel starvation it is, in my view. A blocked jet shouldn't go away after a little wait and then re-manifest.

Took apart the 73 carbs, they look pristine, including the little filters behind the fuel banjo and the float valves. No gunk anywhere. Float height was good. Didn't check for a leak in the floats but that should give other symptoms, correct? Can't be the choke because I didn't switch that. There was old paintflakes in the 73s tank from a shitty paint job, also the tank on the 73 has smaller (on the outside) petcocks because unfortunately we selected a later tank in the restoration process and the original petcocks on the newer tank (does anyone know exactly when the position of the petcocks was changed?) don't fit the drummer. But overall the petcock filters looked very clean and I found nothing cruddy anywhere. I'd emptied out the 73s tank to check the petcocks and flow looked good from both petcocks. Of course I didn't measure anything, but it should be way more than a triple consumes even at WFO throttle. Theories?
 

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I must have drunk something that is clouding my senses today. This is another post that doesn't really help us to help you!
Please clarify -
  • 73 & 74 what?
  • Which one was losing power?
  • Did swapping carbs and tanks fix the problem?
  • Which tank has the problems?
  • Have you checked fuel flow from whichever tank has the problem?
 
Regardless of Rob's important questions above, you'd have to have pretty severe restriction of fuel flow to have problems at 2800rpm. My SFQ tank has have filings and metal crud blocking the petcock filters three times since I got it running. Firstly, it's highly unlikely to be affected on main tank, with the intake tubes well above the floor of the tank (not so reserve), but even on reserve I wasn't experiencing any problems with fuel starvation below full throttle and above 5000rpm.

The filters into the carbies are clear? Two sets of carbs, no change? I'd be suspecting ignition if it were my bike.
 
OK. Gotcha! Making more sense. Something going on in the emulsion tube passages from the air filter side. Have seen this on Dells.Jets pristine, internal passages not so pristine ...
 
Not germain to this topic.... FWIW and stated some time back from myself, put small neodymium magnets adjacent to the fuel taps on the outside of the tank, one each side of the taps, 10m/m by 3m/m or better are ideal ( low cost anywhere ), noted that even certain rust retained it attraction to magnetic fields, be surprised how well these magnets trap tank particles, before the taps.

Every few years, when tank is empty slide in a magnetic tipped telescope rod at the collected debris, remove the outside magnets and collect the debris through the fuel filler. Refit the outside magnets, being doing that for many years now. HTH j.
 
iis_iis said:
Not germain to this topic.... FWIW and stated some time back from myself, put small neodymium magnets adjacent to the fuel taps on the outside of the tank, one each side of the taps, 10m/m by 3m/m or better are ideal ( low cost anywhere ), noted that even certain rust retained it attraction to magnetic fields, be surprised how well these magnets trap tank particles, before the taps.

Every few years, when tank is empty slide in a magnetic tipped telescope rod at the collected debris, remove the outside magnets and collect the debris through the fuel filler. Refit the outside magnets, being doing that for many years now. HTH j.
Click to expand...
Very cool idea John! I only last week thought of putting magnets INSIDE the tank but wondered about the logistics of such a plan. For a magent-igno, what is a 'neodymium' magnet? Can I buy one at the local Coles? :ROFLMAO:

Been using a magnet to pull all the metallics from the gauze filters. Other than metal filings I think the tank is very clean inside.
 
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