Modern Vespa

I'm a Shifty guy who has suddenly found myself with a Twisty… and I don't know what to do with it.

I've been riding and wrenching Vespa P200s for about a decade and I pretty well know my around them but now I've picked up a non-running 2005 ET4 and I don't know how to begin to get it operational again.

It has been sitting in a garage for about 10 years so the first thing I did was replace the battery but the starter motor won't turn over. I get instrumental panel lights, turn signals, brake and brake lights but no headlight and nothing from the starter… not even a click. I checked the fuses and made sure the Power switch was on but I'm still getting nothing.

Is there something I'm missing? Any suggestions as to what I should try next?

For what it's worth, I tried kick starting it but couldn't get the engine to turn over even when standing on the kickstart lever. I was thinking about taking out the plug to make sure the engine isn't frozen, but it looks like removing the plug is a major job itself. Maybe tomorrow.

Maybe put some petrol in the tank

Any information to go on from the previous owner? like the engine is seized?

The tank is empty but I'll add ga... uh, petrol once I can get the starter motor to turn over. Is there some sort of fail-safe mechanism that prevents the starter motor from operating when the tank is empty?

No, PO hasn't even looked at in years. He know nothing

Is that really only 106 miles or has it had a new instrument cluster fitted?

In that case it may well be much longer than 10 years. Probably all gummed up.

Hauling too hard on the kickstarter will generally crack the transmission cover so be gentle.

Yep holding the brake to start with

"Won't start" diagnosis for beginners

Do you hear a 'click' when you hit the starter button? If not, then the starter relay isn't even trying to 'make'.

ET4 manuals here: https://manuals.wotmeworry.org.uk/Vespa/ET4/

Note the headlight is AC powered, so won't come on until the engine is running.

flybynight already mentioned it, but I will say it again just in case, since it is such a tiny detail and potentially what is stopping you. Probably not, but just in case:

There is a starter interlock that depends on a brake lever being depressed. Either one will do, but check both.

And the kill switch as well, but I think you already mentioned the "power switch".

And the kick start is literally useless. It won't work and you'll crack the transmission case. Do not use.

In my experience with 2001 ET4...
Removing the plug is a piece of cake, it's putting it back in that is a real PITA!

Son of a Bitc... uh, Gun! I had no idea that there was an interlock on the brake lever. I saw that the manual says to set the brake when starting but I thought it was just for safety's sake so I ignored it... as I often do for things that are good for me. Tonight I pulled the lever and got power to the starter. It didn't turn over but that may be because the battery I used was from one of my P200s and it may not have had the power to turn over the engine. I'll work on it more tomorrow.

Yes, 106 is correct mileage. I got this from a guy who has been one of my closest friends for more that 50 years so I know the speedometer is correct. He and his wife both bought Vespas in 2007 and she decided that she didn't like hers after just 106 miles. It took her 15 years to decide that she wasn't going to ever ride it again so he sold it to me knowing that I would enjoy it... even if it wasn't a Shifty.

Good to know

When removing or installing the plug, it is easier off the center stand as you will find you get a little more room to maneuver the cap off, plug out, etc... Have someone hold it, rest the left side of the scoot against your leg, or find a way to tie it off.

An open-ended 19mm wrench helps lever the cap off.

Also thinking as the scoot is a brand new old scoot maybe the sparkplug wrench is in the toolkit that comes with a new old scoot with 106 miles, some awesome tips below

How to get vespa et4 spark plug out??????

I didn't find a tool kit but I have plenty of tools from working on my P200s. Good tip about the 19mm wrench

What is the purpose of the aquamirine insert in the throat of the gas tank filler tube and how can I remove it. It is preventing me from inserting my siphon hose.

I would imagine it is to stop putting diesel in, as diesel nose is bigger

some tips below

More info which might be helpful:

https://modernvespa.com/forum/topic161429

https://modernvespa.com/forum/topic177828

That makes sense

Useful info. Thanks

Well. I'm getting there.

I drained the 15 year old gas (ugly stuff!) and replaced it with fresh gas and now it will start without the Starter Spray but it runs badly. It won't idle and when I can get it to rev at a higher speed it won't do so consistently. I have to constantly blip the throttle and I can keep it going for a couple of minutes but eventually it will die.

It looks to me like a fuel feed issue so I'm thinking clogged jets. Does that seem reasonable?

I'm little intimidated by the thought of having to pull the carb. I can pull the carb on my 2-stroke in just a few minutes but the ET4 carb looks to be a lot more involved. Lots of hoses and other connections. I've been watching videos so I'm sure I can do it but I'd welcome any tips.

The carb on these is nothing to be afraid of. Once you've done it once or twice, it's a piece of cake. You need to loosen the hose clamps on either end of the carb; it might be worth removing the airbox to get more wiggle room. You need to remove the fuel line, throttle cable, electrical connector for the carb heater and the electrical connector for the bystarter assembly. The carb should come out with minimal fuss.

I suspect that the chamber between your venturi and pilot jet might be gummed up. Your accelerator pump may not be working either.

The carb is a Keihin CVK and parts are still available; if Piaggio doesn't have them, someone else will.

If you need more detail, I'll get some pics from the CVK off of my LX150.

Change a few numbers and it is the story of my 125 Primavera.
Also that of my ex´s mountain bike and currently (pun intended) her electric mountain bike.

to you Fatbear5.

Carb work is easy on these scoots. AZ has it down right. While you're at it, change out all the vacuum and hose lines. Also check the rubber intake manifold which is known to crack. If you are feeling energetic, lose the EVAP system and save yourself a headache down the road.

I'll give it a shot. Thanks for the step by step instructions

Sounds like a smart thing to do

Ok, I've pulled the carb... well almost. I still have two electrical connections I need to deal with but I don't know where to disconnect them? I've followed the wiring as best I can but haven't found a connector for the two cables. Am I missing something or do they disconnect at the carb? If so, I'm guessing that I would unbolt the smaller wire on the left but where would the larger wire, the one with the black cap, unplug? Does it just pull out? As you can imagine, I don't want to try unplugging something that doesn't unplug.

Getting the two larger carb hoses disconnected was a bugger and I'm worried that putting them back on the carb is going to be a SOB. I'll probably heat the hoses but I'd welcome any other tips.

I also had a hell of a time getting the orange-labled hose off. I finally had to give the hose clamp a rather firm twist. I'm thinking that that hose is the fuel line but I was surprised that no gas came out when I finally got it off the carb. Is that telling me something?

Orange is the fuel line.

The thing above it is the bystarter. There should be about a foot of wire and a red two-pin plug. Lube the connection before passing down on that tab. You may need to wiggle it a bit.

The bolt with the wire is the carb heater. There should be a black two-pin connector about 6-8 inches down the wire; remove it like the red one. I don't recommend unscrewing it with the wire connected to the harness as it might damage the connections.

I didn't see any connectors when I looked this morning but now that I know what to look for, I'll check it out tomorrow. Thanks

GOTCHA YA YOU BASTARD!

This morning I found the two connectors hidden in a black sheath. Of course, I couldn't slide the sheath out of the way and had to slit it to get at the connectors but I'll tape it back together when I reinstall the carb. Considering how tough it was to get the wires out of the sheath I expect it's going to be a son of a bitch putting it all back together. (I tried unscrewing the clamp that holds the sheath in place but couldn't do it.)

Thanks oz slynch for your help with this.

Damn! I couldn't slide the sheath out of the way because I was trying to unscrew the holding clamp... the one that unsnaps instead of unscrewing. I sure wish I'd figured that out before busting my butt trying to disconnect the wires.

As I've said, these Twisties are sure different from my Shifties!

Ok, what's next?

I've drained the old fuel (Had to use the fuel tap at the bottom of the tank because I couldn't get my siphon to work), put in fresh gas and cleaned the carb lines, body and jets. I did not remove and clean that small piece that goes under the main jet as I didn't want to have to remove the diaphragm (Yet another Twistie part I know nothing about) to get it out. I cleaned and adjusted the mixture screw to 2 turns (where it was before) and put everything back into the scoot this morning.

It starts up easily and idles pretty well so I'm thinking that the idle jet is clear, however when I try to blip the engine, it stalls and dies. I know that the main jet is clear so I don't know where to turn next.

Does anyone have a suggestion?

Did you dismantle and clean out the accelerator pump? That's the plunger near the carb intake. It has a hole in the bottom of the float bowl that feeds it. You can test it by taking the bowl off, putting fluid (water works) in the bowl and pressing the plunger rod down. It should shoot a bit out of a hole in the lip of the float bowl.

Assuming that works, find the corresponding hole on the carburetor body and shoot some carb cleaner into it. It should spray a fine jet of cleaner out of the little brass nub in the carb venturi, firing towards the throttle plate.

Barring that, I'd get a metal guitar string, like an Ernie Ball #10, prop the throttle plate open, and poke it through the four holes in the venturi floor to ensure they're not blocked.

"The clamp that doesn't unclamp" should be pretty cooperative if you jam a flathead screwdriver into the gap and twist.... unless you figured that out already...and they pop closed even more easily...

Yeah, I figured out that one and all is good now. Just so many things I'm not familiar with

It's not always easy- even with MV's help I've been stupidly stuck on stuff or had to undo things more than once.....good luck!

Damn, I hate being ignorant. But in my defense, I would say... well, actually I don't really have a defense. I just didn't do enough research.

Apparently there's a little trick about reconnecting the airbox cover and hose in order to make the engine run. I hadn't bothered with doing that since I was frequently using starter spray directly on the filter element to start the engine and I didn't think it mattered. (It's doesn't on my P200s.) But then I was watching more general videos on the ET4 just in order to learn more about them and ran across someone saying the engine won't run if the airbox is not connected. Suffice it to say that I did a quick repair and just took my first ride around the block

As I've been saying, these Twisties are a lot different from my Shiftys.

All that's not to say that I don't appreciate your help az_slynch. I had cleaned the accelerator pump but did not look at the throttle plate. I'll add that recommendation to my growing maintenance file in case I have to (God Forbid) remove the carb again.

Thanks to all who helped me with this. I'll no doubt have more questions and I get more and more involved with this ET4.

What is the purpose of air filter oil? Is that to capture very find dirt? Any recommend brands?