Modern Vespa

I was gifted this pretty mint 2003 Vespa ET4. It has been sitting for several years and does not run. From what I understand it had issues, she parked it, and it sat for 3-4 years.

The last owner gave me a stack of receipts and among them are a Malossi 187cc kit (2012 receipt) and a Keihin CVK 2600A w 82 main jet and 35 idle mixture jet(2016 receipt).

I don't know anything about Vespas, I grew up tinkering on dirt bikes but the CVT and engine mount style are new to me.

For starters, the plan is:

1. New Spark plug
2. Oil change/filter
3. Air filter
4. Remove and clean carb; replace cracked carb manifolds
5. New battery
6. Fix kick starter (does not return to position)
7. Replace fuel lines that rotted off

and see what happens.

I have a couple questions:

1) the oil change should be the same even with the big bore kit, correct?

2) the kick starter is very easy to spin up and down, I do not feel much (if any) compression - what could cause this? the broken spring? the broken fuel line? how much resistance should there be? Is it a worthwhile fix - I hear it can be finicky at best?

3) the fuel lines have basically rotted off, but I can hear fuel in the tank; why did it not drain out? relatedly, how should I best remove the old fuel, and should I/how should I clean the gas tank?

Is there anything else I should know? Common issues or think I should check? Any and all advice appreciated

If it's turning the motor over with no resistance, check to see if the spark plug is installed. If it is, there's likely a new set of rings in your future.
The motor is very simple, and if you know anyone who works on ATVs, you know someone who knows how CVTs work.

the fuel tap is vacuum operated, apply some vacuum to the source line and the fuel will come pouring out of the supply line, keep the vacuum on it and it'll drain most of the tank. give the bike a little wiggle and shimmy shake to get the dregs.

then unscrew the clamp and remove the tap. be advised more will come out. you can stuff a junk towel or t-shirt, but absolutely not the tablecloth up and around the motor and over the exhaust to catch most of it. then rinse the tank out with some fresh fuel and a little shake on the bike and you'll be fine.

install a new tap. so, you should probably order one of those before taking it all apart.

also, if you used the table cloth you should probably get a new one.

the kickstarter might be stripped, or the cog/gear may not be engaging. you'll need to either remove the kick arm and check the splines (easy) or remove the transmission cover and see what's up.

it should no kick over smoothly with no resistance. hopefully something is waxed in the kickstart assembly and not your rings-- or something else.

also, the kick mechanism is terrible on these. more transmission cases have been busted and cracked than bikes have ever been kickstarted. use the electric starter.

On the ET4 that I got back into running state (never would have made it without Greasy's advice) the kick starter would go down without cranking the engine and then you'd have to pull it back up by hand.
I just took it off and put a plastic cap over the shaft.

Thanks for all the advice.

Here are a couple pictures of her - I've named her Perla. She's going to be a beach cruiser/commuter here in FL.

She got a bath and she's been moved into my living room (up three flights of stairs lol) and I'm starting her rehab.

The fuel lines are 3/8ths, correct?

Getting ready to remove and clean the carb - any tips/tricks/things I should know? Why is the vent line(?) capped with a screw?

Somebody nixed the EVAP system. There are cleaner ways to do it, but if it works.....?

Good luck with the project.

3/16ths fuel and vacuum lines. Remove the vacuum line and all the extra tees, etc, and run one line directly from the bottom outlet of the fuel tap to the vacuum inlet on the intake manifold. If you need a new Intake Manifold, consider getting the European one with only one vacuum connector. If you don't, go ahead and plug one of the outlets. Run the other line directly from the tap to the carburetor.
Make sure the fuel tank is vented. Sometimes people don't do that when they disconnect the evap system. If you are unsure, go ahead and put a straight pin hole through the O on the gas cap.


https://scooterpartsco.com/et4-air-and-fuel-c-3637_3640_3734/intake-manifold-for-vespa-150-single-vacuum-line-p-9213.html

Firstly get a manual and watch Robot on these videos. There a 7 in all on resurrection of ET4.
?si=69zYKiwDktVyUqQL

As you have the 190 kit, I'd strongly advise getting a LiFePO4 battery - it should not be more expensive than a good SLA. They maintain a higher voltage under load and better CCA, ideal for the higher compression of the Malossi kit.

Ok thank you.

To make sure I understand the fuel line: one line from the bottom of the petcock to the manifold, and one line from the top of the petcock to the carburetor, correct?

What is the big square box that has two hoses coming out? (See pic) can I bypass everything else in the evap system and just use the two lines described above?

I bought a Piaggio PTX12-BS battery, should be ok?

Is there a way to change the spark plug/air filter without removing the shock and dropping the motor?

I have done a spark plug without dropping the engine. It is a PITA but can be done. Put on center stand and can be done. I think scooterwest has a YouTube video on it

Zero reason to replace the spark plug on a 4 stroke bike unless the mileage is high. Diagnose before throwing parts at it. Check for spark. Clean the carb and replace any old fuel and vacuum lines. Disconnect the fuel line at the carb and the vacuum at the intake and suck on the vacuum line and see if fuel flows. Total parts bill is about $10 to see what is going on.

the big box is the charcoal canister. one line runs up to the manifold, you can remove that and cap the vacuum port on the manifold fitting. or if you upgrade to the new manifold it doesn't have this provision, so you just have a small fitting to run the line to petcock.

correct, vacuum on the bottom, fuel on the top for the tap.

removing the evap line that runs to the carb and attaches just under the diaphragm cap eliminates all the evap stuff from the equation.

doing the plug without dropping the motor is a pain, but doable. I'd do that and the air filter at the same time because if the motor is down the filter box is totally exposed.

But make sure you vent the tank.

Well, I'm off to a rough start. Perhaps foolishly, I did not order a new petcock, I was hoping to use the one on there as it looks like it's very clean, and I was going to use a fuel filter to prevent any potential contaminants from getting in. I put on some fuel line to start draining the gas, and as soon as I did the petcock started leaking near the top.

I managed to get the gas all out of it, but now I'll need to replace the petcock unless I can somehow reseat that one to prevent further leaking.

Greasy125 recommended a new one, is there a reason not to use the old one (other than its old and might be gummed up)? Is there a trick to sealing/installing a petcock?

In terms of venting the tank, I saw something about drilling a small hole in the gas gap. Is there a better way? Has anyone plumbing in some sort of vent line? My dirt bike has a breather tube out of the lid that prevents stuff from getting in, how doable would something like that be?

Also, given that its a suction system, if I remove the evap and just do the two lines will a fuel filter cause me any issues?


Unrelated . . . what's the best way to wash a gas-soaked tablecloth towel

The UK ET4s of that era just used the tank vent line (just below the filler) routed across to the left-hand side and then down to the ground. This will prevent much if any spillage if the bike tips over.

Best not to drill a hole in the cap.

Evap system is out!

Manifold comes tomorrow - carb clean, battery install, fill her up and see what happens.

I also pulled the petcock and cleaned what I could. No visible issues with the O-ring so I put it back in and am hoping for the best.

Fuel tank vent was cut off the evap system leaving the hose as long as I could, then the hose was zip tied to the frame rail that the evap was mounted to.

I always recommend a new tap because the diaphragm is known to fail internally and then it's stuck in the "on" position. or, the "off" position or works intermittently and you chase your tail on a fuel delivery issue. the o-ring can also become compromised over time.

it's just good practice to refresh it when you do a complete fuel system rebuild.

as you found out the ET has a port off the filler neck, that runs down to the roll over valve. clip that and zip tie it up somewhere out of the way and directed so that it won't leak on something critical if accidentally overfilled. problem solved.

as for the table cloth, I just spray mine off on the drive way with a hose, much to the chagrin of my neighbors. fabreeze the bejeezus out of it and it'll be fit to return to service. no one the wiser.

or, just use it to start a bonfire.

So have I. I'm not sure where the whole "gotta drop the engine to change the spark plug" idea came from. But it's not true. The tool that works best for me to change the plug on an ET4 or LX 150 is the one that comes with the factory tool kit, but we've changed them with spark plug sockets too. It's not a Chevy Monza V8, you can get to the plug.

the factory tool with a 13mm ratcheting wrench with a flex head is the magic to make it happen.

or a $110 1/4" drive wobble head snap on ratchet with a short 13

just act like you're picking a pocket and it's fine

Did some monster rivet that reflector to the body?

Yep, riveted reflectors all over her.

Carb was removed, air boot and manifold replaced (both cracked).

Carb was cleaned, was is pretty good shape. Wish I had a new seal for the bowl but unfortunately didn't. Pilot jet 34, main 82.

Fuel/suction lines plumbed, battery is on the charger. Time to see if rubber meets road.

Hoping I plugged everything into the right places lol

It runs. So unbelievably surprised, but stoked!

Fired right up first try, putted it around the local street for about half a mile.

The oil light was on at first, but eventually turned itself off after a bit of driving.

Ended the ride early as the tires were (both) leaking. New tires are next I suppose.

Two issues:
1. The 'Piaggio' light was blinking intermittently. From poking around a bit, this is not the check engine light (?) but the immobilizer, and it was indicating 'all is well' - does that light always blink? Even after its off/key is out?

2. The fuel filter was bone dry. I primed the filter and carb before I fired it up, but after the ride the filter was empty. I took off the vacuum tube and sucked through it and no gas would fill the fuel filter. What gives? That's how I originally primed it...

Less important: the oil light - how do I reset it if it turns back on?

light blinks for 24hr after shut down. on start up, one blink only. any more than one blink and there's some type of ignition fault. (don't worry about it and leave it to be a bridge crossed later) don't worry about it, the fuel will flow once the needle valve opens in the carb. it's not like a traditional set up where the pump is forcing fuel into the line and thus the filter. also, the fuel tap has a filter so I rarely recommend running a filter. there is no reset for the oil light. it's illuminated by a pressure switch. if the light is on: you have no pressure, you have low oil, or the connection is loose/corroded (or possibly a bad sensor, unlikely though). have you done a oil change yet?

don't ride it till you get the tires done. and new stems when you do them.

New tires are finally on.

However now the motor keeps cutting out. It starts right up every time, even after it cuts out.

I thought perhaps it was a fuel problem caused by the fuel filter I had on, so I took that off, but the issue persists. What could it be? Seems fuel related.

I did the evaporation system delete, so I only have one line, running from the petcock to the manifold, and another from the petcock to the carb.

I ordered a new petcock and it has a cover for the evap line. Is it possible to not have an evaporation line?

It is an intermittent but persistent issue where the engine stumbles at idle or while cruising. Always starts back up though.

It's also really hard to push - I feel like it used to glide and now it doesn't want to roll freely, even when it's off. The front wheel especially will not spin if I'm not actively forcing it. Tons of drag/friction. Could I have made a mistake installing the wheels?

Plz help

Are you running fresh fuel?

What do you mean about cap for the evap line? I can't see any reason why a petcock would have evap parts. They often come with ports capped to keep dirt out in shipping- could that be what you mean?

There is definitely something wrong with your wheel, as it should turn freely. I mean, some light dragging on the disc brake, but not a struggle to turn by hand.

Fuel is fresh, ethanol free 87.

Now that I think about it I wasn't having issues when I ran 93 at first. Hmmm.

I think the disk might be dragging but I'm not sure why that would've started happening after a tire change? The rotor isn't on the wheel or 'involved' in that process at all…?