Modern Vespa

I have a 2007 LX50 with 575 miles on it. Bought it used a couple of years ago from a Vespa dealer. It was freshly serviced when I bought it. Was riding it and it just stopped running. Starter turns quickly but the engine does not fire and turn-over. I checked both brake levers and they light up the brake light. I rocked the "Kill-Switch" back and forth and tried staring it again. All it did was crank the starter and no engine combustion.

It is almost like it is not starting like a car with an imobilizer would not start without a programmed key?

After some research on this forum I concluded it is possibly one of these issues:

Ignition switch
Kill-switch
CDI
Voltage regulator
Spark plug
Spark plug wire
Fuel line
Vacuum line
Carburetor

Any advice on how to check each component?

Advice on where to buy parts.

Thanks in advance.

Will it fire with ether?

The engine cranks fine but the engine does not fire at all. Like it has no spark or fuel? Not even a slight sign of combustion. Just cranking.

I will try physically checking the plastic and rubber fuel and vacuum lines tomorrow.

I think it is somehow electronic related? Like I said it cranks strong but no sign of any combustion at all?

Not sure what you're asking about firing with either? It cranks fine but has no signs of any combustion what so ever. Thanks.

I don't remember if the dash gages light up when the ignition key is turned to the start position? The dash warning light do not light up when cranking. I don't think the digital clock lights up either? Would this provide any clues about what is wrong?

I will double check if I am remembering this correctly about the lights tomorrow morning.

Your engine needs three things to fire: fuel, air, and spark. (To that I would add compression because without compression the engine might fire but would produce no power.) Spraying ether (starting fluid) into the carb will confirm spark, and rule out fuel delivery if it "fires". If it doesn't, the next thing to check would be fuel. Is fuel getting to the carb? Is vacuum getting to the petcock (fuel valve)?

You'll have to go through your list one item at a time until you find the cause of the engine not starting.

Good luck and keep us posted.

Remove the sparkplug, put a new sparkplug in the plug holder, then hold the tip of the sparkplug against a bare metal area of the engine, and engage the starter. Look to see if there is strong consistent spark from the sparkplug. If not then you know you have a CDI or kill switch problem. If there is strong spark, then you have a fuel problem or valves problem.

Dash lights don't matter much, unless they're telling you the battery is completely dead. But as you say the starter is turning, so...

It's what we used to do to check car ignitions back in the day. This is what I was planning on doing this weekend. I will physically inspect the fuel and vacuum lines. Pull the plug and check for spark.

The scooter has less than 600 miles on it. How common is the valve adjustment issue?

I was wondering about compression loss if valve clearance is not correct?

I am going to pick up some staring fluid to see if it will fire.

I just thought maybe there was some kind of electronic issue that might be a tell tale clue with the voltage regulator or something?

Battery is definitely strong. The starter cranks fast. Just no ignition and combustion.

Does the 2007 LX50 have an immobilizer key and ignition?

Could it also possibly be a bad voltage regulator? Any way to test a voltage regulator? Any way to test a CDI or kill-switch? Can you jump and override the kill-switch?

This, just do this. You may be able to remove the air filter, do a bit of spray in the intake and temporary install the filter. Don't drown it with spray. If there is any sort of spark, it will pop.

I am waiting for a new plug tool so I can pull the plug.

In the mean time I was looking around and noticed the clear plastic tube that runs along with the black fuel line is broken at the clamp. One end goes to the gas tank and the other end goes to the carb. It is broken at the gas tank side, just under the gas tank. It broke right at the clamp. Is that clear plastic tube a vacuum line? What size is it and where do I buy a replacement? Would that broken clear plastic line be the cause of the engine cranking but not firing?

Also is there a way to drain the gas tank?

Thanks.

Where is the petcock? Is the petcock (fuel valve) the part the clear vacuum tube is attached to under the gas tank? I just noticed that clear plastic tube is cracked right at the clamp and no longer attached to the part. The clamp is still there so the clear plastic tube broke off right at the clamp.

Also the clock and check engine light does not illuminate with the key turned to the ON position. Is that normal? The head lamp also is not ON when I turn the key to the ON position. Does the head light only turn on when the engine is running?

The head light on my Honda scooter turns "ON" whenever the key is turned to the ON position. Not sure about a Vespa, I don't remember?

Is there a fuse or fuse box somewhere?

That's it. You won't get any fuel to the carb with that cracked tube. Replace it.

First, replace that vacuum line. You can use any hose with similar diameter. Home depot sells them.
With the new vacuum line on, remove the fuel line from the carb, and put it in a bottle. Then remove the vacuum line from the intake manifold, and suck on it with your mouth. That will cause the petcock valve to open, and for fuel to fuel into the bottle. This is the simple way to drain the tank

So the suction from vacuum opens a valve in the petcock that allows allow fuel to flow into the carb?

Thanks!

Thanks!

Definitely sounds like fuel starvation. I spotted that right away.

The vaccum line first broke at the petcock. Then the other end. The vacuum line broke at the carb end after just moving it a tiny bit. Was dry rotted and brittle. I pulled the vacuum line out through the harness and there was a filter or something spliced into the vacuum line. I blew through both ends and air passed in both directions. What is it for? Is it a in-line filter or valve? Is it needed? Thanks.[/img]

That's an inline vacuum filter, it stops things from getting sucked into your intake manifold. You should have it. Just replace all the vacuum line hose, and reinstall the filter.

The vacuum filter has crimp style clamps which are probably not reusable. I guess I will have to find some small clamps that fit. Hopefully I can get the clamps loose or off without damaging the plastic filter nipples. Thanks.

Zip-ties will be fine.

This is the part number for the vacuum filter anyone who might need one in the future.

Piaggio 624522

I didn't think of that. Thanks!

Filter not necessary. I you check the Vespa parts books for the various carbed models, many years/models don't have it.

What's critical is hose material that can take the heat. I tried several generic replacements before I threw in the towel and ordered from Vespa.

Quite! If the hose gets cracked so debris can get in, the engine won't be running anyway. You do need a filter in the petrol line though.

You have me thinking about this. Maybe I should order the vacuum hose form Vespa.

I bought some clear 3/16" fuel-vacuum line for small engines from an auto parts store. I wondered if what I bought will soften or collaspe when the engine heats up. It is definitely more plyable than the original vacuum hose. I am not sure if the original hose is originally as stiff as it is now or if age is the reason. It is harden to the point where is is brittle. That is why it broke at both ends.

That'll be fine.