Modern Vespa

Hi all
I neen help please my girlfriends vespa Et2 is started to run bad. Its been find up till now. I have taken the carb off and stripped and cleaned it then started it up and it ticked over and revs ok so i left it ticking over for 30 minutes till my girfriend got home from work so i could show her its was ok but i went to rev it to show her it started bogged then cut out. I started it up but it took time to get it running then rev it and it bogged and cut out. It pissed me off so i left it for abit then went back out to try it again. I started it up but it was running bad bogged and cut out. i started up again then it bogged and started slowly going into high revs. Its done my head in it was running ok up till now and ive had the carb off two times and stripped and cleaned it.

Did you clean AND poke out the atomizer above the main jet? Needle pokes through it from the top and the main jet sandwiches it from the bottom.

When look at the carb upside down where the main just goes do you mean the brass part under the main jet. No I clean it with that part in.

I forgot to ad it's a dellorto phva 17.5 rd carb

Definitely remove and clean anything and everything you can in there.

Did it run perfectly before? Or new aquisition that you're feeling out? What's the mileage?

How do I remove it. It ran ok just bogged abit before it got to 40 but I was told the main jet wrong. I got new main jets coming tomorrow. it's got a 68 main jet in there at the moment but I was told try a 60. It's been unrestricted.
Not sure what you mean feeling out. The mileage is 018557

Is the rest of the engine is stock (ie there's no cylinder kit installed)?

Also, what's the air filter like (they like to fall apart when they get old)?

You're only just up the road from me if you need a hand - I miss wrenching on my ET2. 😇 👍

The cylinder and piston is a 50cc standard. It's just been unrestricted. Exhaust and carb. As for the filter it's not falling apart but it's not great. I plan to replace it so il order one tomorrow. I stripped the carb again but this time I removed everything. Where about are you. I'm in burnham on sea. Hopefully il get it sorted if not I might need a hand. I'm ok with px and T5s I own a T5 classic but the autos I'm just getting my head around them. The ET2 is my mrs scooter I talked her into it. She's about to do her cbt. Thank you for the offer.

PM sent. 👍

🛵💨

All the jets (in this pic) can be unscrewed - gently poking a thin needle through them can help clear them if they're blocked.

Under the main jet, you'll find the atomiser - you can check all the holes in that are clear too.

My 17.5mm carb came with a pilot jet that's too big of the box - so had to order a smaller one. Also, I swapped to an A22 needle and it ran a lot better.

I had installed a 70cc Malossi cast iron kit though - so my experience with the final setup will be different to yours. I didn't get on with the A7 needle.

You'll get there - it's just a bit of a faff to get things right sometimes.

Ps I had an issue with my fuel petcock - it all seemed fine when I tested it but replacing it sorted the difficulties I encountered later on.

Thanks for that bud. I will take a look at the needle. I forgot to mention it almost ran out of fuel so I topped it up. The fuel tap has a filter inside so maybe shite got into that. Just a thought

Hi bud could the problem be the mixture screw. I didn't count how meny turns when I took it apart. Are all et 50s set the same of different. I set it to 1 1/2 turns out

Hiya,

If the idle jet is about right, then it's somewhere in that ballpark.

No reason not to start at 2 turns and slowly go either way to see what works best.

I think mine was at about 2 1/2 turns when the idle jet was too big, so got a smaller one and now it sits at 1 3/4.

Based on reading other posts, it seems the PHVA 17.5 might be a bit tricky to setup. I recall reading someone going back to the original 12mm Weber carb due to his struggles. I think that's how it went down anyway!

🤞

A Weber 12m carb was put for sale on Facebook yesterday. I've just messaged the guy.

What they worth. He ask me to give him an offer. https://www.facebook.com/groups/482923808526172/permalink/2609441922541006/

Good question - I'm not sure on their value… if it has the stock jets/needle/slider it should take some guesswork away.

offerd him £15 see what he says. I did say he dont know if its working or not.

Last actual professional I asked about doing a 70cc kit with a 12mm carb, they said don't do it.

PH carbs are usually pretty solid. Where in the rev range are you having your problems? Idle? 1/4 throttle? 3/4? Full?

About throttle 3/4 throttle then it cuts out. I've cleaned the carb again and this time I did it without the atomizer in. I've ordered some new bits. Carb gaskets, Filter foam, fuel and vacuum pipe and a new fuel tap. They're all as old as the scooter so I fort il give it a treat 😆. I'm just waiting for the tap to come them il put it all back together. I forgot to say in my post it almost run out of fuel. Tap filter wasn't clogged up as far as I can see. I drained the tank and the was a bit of brown gunk come out. I hope it will be all ok now. I didn't take the atomizer out when I cleaned the carb so I hope that was the problem. I got to set the mixture screw because i forgot to count how many turns it was. I put it at 1 1/2 turns out.

So if you run at 3/4 you're good all day? When you go full throttle it immediate stumbles?

If you're fine at 3/4 throttle and full is bad, but clears up at 3/4 throttle, then I'd said the main jet is too rich.

Fuel starvation should take a while to show itself as the fuel line and bowl have fuel in it till it's consumed faster than it's coming in. Usually a few minutes at idle and a minute of hard riding.

If you have a dummy tank, swap the hose to your carb and run the test with tank #2 to see if that's the culprit.

Last idea I have is your PH might have a little collar in between the main jet and atomizer? My 19mm dellorto PH did and it caused some headaches. Finally figured out the collar was 180* and causing issues.

I know bud the main jet is too high. It's had a 68 in there but I put a 60 in now. I got a 60 62 63 and 64. I watch a guy on YouTube who derestricted a Vespa ET 50. Standard jet was 54. He changed it to a 60. The tank i cleaned so there's no more shite in there now. The scooter was running ok apart from the jet being to high what made abit of a problem when pulling throttle full back bu I found out about the jet being too big. The problem starting after I had the carb off and cleaned it. I didn't take the atomizer out but I found out I should of so I cleaned the carb again with it out and soked it in fuel with the carb and other parts and use carb cleaner spray and made sure the holds in the atomizer was clear. Hopefully when get the fuel tap this week it will be fine. I do think now it was a blocked atomizer. I hope

Fuel tap come so i fitted it and went on a test ride. The first 5 minutes was ok but i stopped to turn around and it ran like shit. Only do about 5 mph in a bit of throttle. When I pull the throttle back it almost dies. There's a rattling sound coming from kick start side. It's pissing me off now.

Here's a pic of what it should look like behind the belt cover, and a pic of the kickstart mechanism.

Hope that helps. 🤞

Thanks bud I am planning to check in there tomorrow. I really hope the problem is in the but I've got a horrible feeling it's worse. Bud what software did you use to put them pictures on here.was it free. Ones I found I got to pay for. Not worth paying for if I only use it every now and then.[/img]

Forgot I ask about how you put pictures on here I got this site mix up with another one I'm on 😆

You can add attachment at the bottom.
You let it sit and idle for half an hour?
check for a whole lot of carbon on the plug, and then check the compression.
It sounds like it might be running okay until the electric choke cuts off. I'm not sure what derestricted means for a 50cc scooter with a 12mm carb.
If there's a weber carb in it still, you might look at replacing that with the newer Dellorto. Buying an old used carburetor someone took off their bike is usually a waste of time. By the time you are done changing out this and that, you will likely have spent a lot more time and money on it than if you just bought the correct carb to begin with. They do wear out.

I checked the oil pump and found the pipe going to the carb was dry. From what I read about the rattling sound and loss of power the crank, piston and that are fucked because of no oil. I've ordered another engine to swop it around then I'll take the broken one apart and sell it all. When I moved the filter air box I found part of the engine was broken off above the flywheel so it looks like I was sold a crap engine. It's a bit late to take it back we had it since last year.