Piaggio Ciao doesn’t run properly

Miles Ways /

Jun 09, 2020 04:21PM

Hi!

I bought a Piaggio Ciao and it runs poorly. It starts nicely but when I turn throttle it bogs down.

I have cleaned carburetor with carb cleaner and compressed air. Then it was cleaned with the ultrasonic washer. Didn't help at all. Replaced also a spark plug. Then I took the carb from my another Ciao that had exactly the same carb and it worked perfectly. (The carb is Dellorto Sha 12/10.)

Until yesterday the moped started having the same issues, with a new carburetor. If I give more gas it bogs down. If I close partially the air filter the engine runs better but almost sounds like four-stroke.. Too nice for a two-stroke engine.

It sounds like the engine is getting too little gasoline or the jet is clogged. But I had a filter for fuel, actually three of them. I also took filter off to make sure it's not clogged also and there was no difference.

Any ideas on how to proceed with this project?

Re: Piaggio Ciao doesn’t run properly

Pushrod Fifty /

supercub

Jun 09, 2020 04:31PM

Could be a tiny passage in a jet or the carb body that you need poke with a wire strand.

Re: Piaggio Ciao doesn’t run properly

campeona del mundo /

Go to branch

willc

Jun 09, 2020 05:01PM

check the crank seal.

Re: Piaggio Ciao doesn’t run properly

Ike Pipe /

1ke

Jun 09, 2020 06:16PM

2nd crank seal. Even though it is a pain to pull the engine, it is a very simple and cheap repair. Even if it doesn't fix the problem, you'll be glad you did it.

Another problem can be the condenser and HT coil. If they're bad, they can start OK and then bog out and die as they warm up.

Re: Piaggio Ciao doesn’t run properly

Bad Cadillac™ /

toolguy

Jun 09, 2020 07:13PM

Are you running an air filter?

Check for air leaks too as you seem to be sucking in too much air.

Re: Piaggio Ciao doesn’t run properly

Miles Ways /

milesways OP

Jun 10, 2020 11:06AM

Exactly. It's getting too much air or too little gas.

Yes, I am using an air filter. I’ve checked the carb and air filter. I still need to check the engine and seals.

Re: Piaggio Ciao doesn’t run properly

Miles Ways /

milesways OP

Jun 10, 2020 11:09AM

I understand your point but it doesn't explain the case when I close air filter with my hand the engine runs better.

Re: Piaggio Ciao doesn’t run properly

Miles Ways /

milesways OP

Jun 10, 2020 11:16AM

Could you explain how the faulty crank seal cause this kind of thing? I just do not now enough about two-stroke engines..

> Ike Pipe Wrote:

> -------------------------------------------------------

> 2nd crank seal. Even though it is a pain to pull the engine, it is a

> very simple and cheap repair. Even if it doesn't fix the problem, you'll

> be glad you did it.

>

> Another problem can be the condenser and HT coil. If they're bad, they

> can start OK and then bog out and die as they warm up.

Re: Piaggio Ciao doesn’t run properly

Dirty30 Dillon /

hydra

Jun 10, 2020 11:27AM

> Miles Ways Wrote:

> -------------------------------------------------------

> Could you explain how the faulty crank seal cause this kind of thing? I

> just do not now enough about two-stroke engines..

>

> > Ike Pipe Wrote:

>

> > -------------------------------------------------------

>

> > 2nd crank seal. Even though it is a pain to pull the engine, it is a

>

> > very simple and cheap repair. Even if it doesn't fix the problem,

> you'll

>

> > be glad you did it.

>

> >

>

> > Another problem can be the condenser and HT coil. If they're bad, they

>

> > can start OK and then bog out and die as they warm up.

The failed seal is drawing in fresh air at the crank, when you "choke" the filter by covering it you are correcting the a/f ratio by taking away the air through the carb.

Re: Piaggio Ciao doesn’t run properly

P D /

pdcomm

Jun 10, 2020 11:44AM

> Dirty30 Dillon Wrote:

> -------------------------------------------------------

> when you "choke"

> the filter by covering it you are correcting the a/f ratio by taking

> away the air through the carb.

And , causing more fuel to be drawn in , just like using a chock mechanism or enrichener .

Re: Piaggio Ciao doesn’t run properly

Dirty30 Dillon /

hydra

Jun 10, 2020 12:09PM

> P D Wrote:

> -------------------------------------------------------

> > Dirty30 Dillon Wrote:

>

> > -------------------------------------------------------

>

> > when you "choke"

>

> > the filter by covering it you are correcting the a/f ratio by taking

>

> > away the air through the carb.

>

> And , causing more fuel to be drawn in , just like using a chock

> mechanism or enrichener .

Technically, you're getting less fuel, as less air through the carb means less fuel drawn from the jet as fuel is only drawn when air passes through the venturi.

Re: Piaggio Ciao doesn’t run properly

P D /

pdcomm

Jun 10, 2020 12:42PM

> Dirty30 Dillon Wrote:

> -------------------------------------------------------

> > P D Wrote:

>

> > -------------------------------------------------------

>

> > > Dirty30 Dillon Wrote:

>

> >

>

> > > -------------------------------------------------------

>

> >

>

> > > when you "choke"

>

> >

>

> > > the filter by covering it you are correcting the a/f ratio by taking

>

> >

>

> > > away the air through the carb.

>

> >

>

> > And , causing more fuel to be drawn in , just like using a chock

>

> > mechanism or enrichener .

>

> Technically, you're getting less fuel, as less air through the carb

> means less fuel drawn from the jet as fuel is only drawn when air passes

> through the venturi.

Consider the carb vent .

When the throat is blocked , the suction of the motor pulls more fuel in , as it is the path of least resistance .

Re: Piaggio Ciao doesn’t run properly

Dirty30 Dillon /

hydra

Jun 10, 2020 12:54PM

> P D Wrote:

> -------------------------------------------------------

> > Dirty30 Dillon Wrote:

>

> > -------------------------------------------------------

>

> > > P D Wrote:

>

> >

>

> > > -------------------------------------------------------

>

> >

>

> > > > Dirty30 Dillon Wrote:

>

> >

>

> > >

>

> >

>

> > > > -------------------------------------------------------

>

> >

>

> > >

>

> >

>

> > > > when you "choke"

>

> >

>

> > >

>

> >

>

> > > > the filter by covering it you are correcting the a/f ratio by

> taking

>

> >

>

> > >

>

> >

>

> > > > away the air through the carb.

>

> >

>

> > >

>

> >

>

> > > And , causing more fuel to be drawn in , just like using a chock

>

> >

>

> > > mechanism or enrichener .

>

> >

>

> > Technically, you're getting less fuel, as less air through the carb

>

> > means less fuel drawn from the jet as fuel is only drawn when air

> passes

>

> > through the venturi.

>

> Consider the carb vent .

>

> When the throat is blocked , the suction of the motor pulls more fuel in

> , as it is the path of least resistance .

The only way the carb vent would draw air into the motor would be to drain the bowl and allow it through the main jet, at which point you get no fuel anyway.

The path of least resistance in this model is the seal.

Re: Piaggio Ciao doesn’t run properly

Miles Ways /

milesways OP

Jun 10, 2020 01:38PM

Thanks for replies! I managed to fix it.

I had made a crucial error. I assumed that the carb was clean because it was cleaned with ultrasonic cleaner but the jet was clogged with some white residue. Actually, It might have been clean because I drove about 10km with it. Somehow the white stuff has gotten into the jet.

Re: Piaggio Ciao doesn’t run properly

P D /

pdcomm

Jun 10, 2020 01:42PM

> Dirty30 Dillon Wrote:

> -------------------------------------------------------

> The only way the carb vent would draw air into the motor would be to

> drain the bowl

Exactly . The suction of the motor is greater than atmospheric pressure in the bowl via the vent . Fuel gets sucked up the jets ... in and attempt to equalize pressure .

That tiny crack in the seal is less a path of resistance .

Maybe if the seal was gone , but ...

Re: Piaggio Ciao doesn’t run properly

pat splat /

ggspeed

Jun 11, 2020 07:33PM

when u choke a motor it enrichens the mixture, literally sucks more gas in with less air, something about vacuum and air speed and bernouli. Ever check your plug after choke a non runner, its soaked.

MOPED ARMY

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