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LX150
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LX150
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Ladies and gents,

My LX150 with c. 6K miles and no history of problems Quit while running at around 40 MPH on a steady throttle, just a couple of miles into my commute. It would turn over, but no hint of firing up. Battery was strong. I ended up trailering it home.

It's carbureted, and bog stock.

Went to investigate the following evening. Took a suggestion from this forum and tried the brown key; fired right up. Thought I had it sussed, swapped back to the blue key; fired right up.

Tried several times over the next few days; fired right up every time.

My granddaughter uses the Vespa a lot to save patrol money and now I won't trust it.

I had to leave on a trip so haven't had time to investigate any further.

Strangely, my other Italian beauty, a Ducati 1098, did exactly the same thing a couple of months back. I put a MOSFET Rectifier in that and it seems to have stabilized.

Are there any common causes of such behaviour in a Vespa that I haven't discovered yet?

Any advice is greatly appreciated.

Jim M.
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Molto Verboso
2006 LX150 (carbed) | 2007 GT200
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Molto Verboso
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2006 LX150 (carbed) | 2007 GT200
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I am pretty sure the immobilizer only matters when you are starting the bike. So if it stalled at speed, I would not suspect the keys.

Have the valve clearances ever been checked / adjusted? A couple years back my LX150 would stall at stoplights, and the problem went away once I adjusted the valves.

I might also suspect fuel delivery. Are the vacuum and fuel lines in good shape and properly connected? Or are they cracked (especially the vacuum line; only because I think you'd see / smell if the fuel line was cracked and leaking), and therefore not delivering fuel?
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The Hornet (GT200, aka Love Bug) and 'Dimples' - a GTS 300
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The Hornet (GT200, aka Love Bug) and 'Dimples' - a GTS 300
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A cracked vacuum line would do it. Had that a couple of times. They would start fine, and take off fine, but then die some way down the road.
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LXV 150 3v ie. Midnight Blue (Sold) Now Honda Zoomer X
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LXV 150 3v ie. Midnight Blue (Sold) Now Honda Zoomer X
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Very generally speaking.

If it quit suddenly/cut out, it is electrical.
If it dies a bit more slowly/petered out, it is fuel related.
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2007 LX 150 (memories)
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2007 LX 150 (memories)
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Check the spark plug cap. Make sure it is well threaded onto the wire and firmly seated atop the plug.

Oh, and make sure the battery terminals are tight.
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2007 LX150 Daring Plum Leonardo Da Vespa
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2007 LX150 Daring Plum Leonardo Da Vespa
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What year is your LX? Swap out the fuel and vacuum lines. Mine last 4yrs tops. Is the battery the one that came with it? If so i'd change it out. If you keep up with the maintenance it'll go forever. I have 49,600 miles on my '07 LX 150.
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LX150
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LX150
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Many thanks for the suggestions. It is a 2006 (I think!) And I have not swapped out the fuel and vacuum lines. I'm sure there is a procedure on this forum for that. I did check that the spark plug cap was not loose at the side of the road. The battery has been replaced at least twice, maybe three times. Long periods in the garage don't help with battery life.

So as soon as I get back from my current trip I'll do the lines.

Are they standard off the shelf hoses, or unusual Italian diameters?
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Veni, Vidi, Posti
MP3 500, GTS 250 (both 2008 MY), 2013 Piaggio BV 350, 2014 Can Am Spyder RT
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Veni, Vidi, Posti
@madison_sully avatar
MP3 500, GTS 250 (both 2008 MY), 2013 Piaggio BV 350, 2014 Can Am Spyder RT
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Lukyduc wrote:
Many thanks for the suggestions. It is a 2006 (I think!) And I have not swapped out the fuel and vacuum lines. I'm sure there is a procedure on this forum for that. I did check that the spark plug cap was not loose at the side of the road. The battery has been replaced at least twice, maybe three times. Long periods in the garage don't help with battery life.

So as soon as I get back from my current trip I'll do the lines.

Are they standard off the shelf hoses, or unusual Italian diameters?
In the US they may be considered unusual metric diameters, but should be available at most any car parts store.
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World Traveler
2007 LX150 Daring Plum Leonardo Da Vespa
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@judy avatar
2007 LX150 Daring Plum Leonardo Da Vespa
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Make sure that the lines you put in are the same size and length as what you take out. Scooterpartsco.com has some. Good luck
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LX150
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LX150
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Finally got back from travel and got to work on my LX. Sure enough, the clear plastic / vinyl line that tees into the vacuum fuel tap was trashed. I went through the procedure to remove the evap canister and tip over valve (thanks to the great how-to by brtoney on here). All good.

When I took the assembly of remaining hoses complete with T to the auto parts store and asked for vacuum line to replace the clear vinyl portion the parts guy insisted it was fuel line, not vacuum line. Granted, the other two hoses do look like fuel line on my bike. So it now has fuel line - standard reinforced rubber. I expect it will work fine.

Still need a new air filter, and just discovered there is a secondary filter for the engine cooling air. Quick top up of oil levels and should be good to go!

Thanks for all the advice.

Jim M.
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2007 LX150 Daring Plum Leonardo Da Vespa
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2007 LX150 Daring Plum Leonardo Da Vespa
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Cool. Swap out the fuel and vacuum lines and you'll be good to go. Yes get rid of the evap crap. Can only cause you headaches.
⬆️    About 1 month elapsed    ⬇️
OP
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LX150
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LX150
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Air filters in, bike starts on the button, idles smoothly and runs great. Thanks for all the advice and knowledge. Priceless!
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