SHA Dellorto fuel leak ?

Hi All ...my very first post here...

Working on a Vepa Piaggio Ciao 60cc - I am getting leaks with two carbs a 12/10 and a 13/13.

When static, I get no leaks of fuel air filter side.

When I try to start and if by miracle it runs a bit... I see a few drops of fuel that leak out air filter side.

Is this normal?

I have cleaned the seats, new floats, new needles... noting seems to stop this.

I would understand if this happened only to one carb... but both?!?! That seems a bit too coincidental...

MTIADC3

Re: SHA Dellorto fuel leak ?

It's 4-stroking,and spitting back thru the carb. Make sure points are properly cleaned and gapped and spark plug is clean and gapped, air filter is not too restrictive, and main jet is not too large.

Re: SHA Dellorto fuel leak ?

A little fuel fog is normal, if your timing is off then you will get lots,on reed engines if the reeds do not seat right you will gets ots (or lots and lots)

Re: SHA Dellorto fuel leak ?

sounds like its flooded. is the choke releasing? is the plug super wet n fouled? Jet size? Try drill starting w a new plug w throttle wide open.

Re: SHA Dellorto fuel leak ?

Barry (Bob) Brown /

jet size might big a bit big?

Re: SHA Dellorto fuel leak ?

> Don Ohio Wrote:

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

> It's 4-stroking,and spitting back thru the carb. Make sure points are

> properly cleaned and gapped and spark plug is clean and gapped, air

> filter is not too restrictive, and main jet is not too large.

I went through the ignition a few times and set the gaps on a bench. The points and plug are new.

I guess it could be the jet size... but it was doing this with both of my carbs, a 13/13 and the 12/10. I will try the stock 42 on the 12/10.

Could it be an air leak between the carb and inlet? Spraying cab cleaner there kills the motor.

Re: SHA Dellorto fuel leak ?

Definitely cure the air leak .

Then check timing . Not just the points gap .

Re: SHA Dellorto fuel leak ?

ᴛᴇʀʀʏ ᴅᴇᴀɴ /

so iirc, Vespas don't have adjustable timing. basically just point gap size.

also, they are rotary valve and shouldn't get much fuel fog.

you said this is kitted, did you also do any work to the rest of the engine? did you trim your crank or anything? drill your intake?

Re: SHA Dellorto fuel leak ?

ᴛᴇʀʀʏ ᴅᴇᴀɴ /

I see in your other thread that you've opened up the intake, do you have any pictures of this?

also, I wish you had put all of your questions into one thread. it's really hard to keep track of things when there are multiple threads, especially since it sounds like the issues are related

Re: SHA Dellorto fuel leak ?

Apologies for that. This thread went through the classic creep. I initially just wanted to know if these carbs “dribbled” a little out this air filter side and if that was normal.

Re: SHA Dellorto fuel leak ?

> the worst terry Wrote:

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

> so iirc, Vespas don't have adjustable timing. basically just point gap

> size.

>

> also, they are rotary valve and shouldn't get much fuel fog.

>

> you said this is kitted, did you also do any work to the rest of the

> engine? did you trim your crank or anything? drill your intake?

No, I didn’t mess with the crank valve timing. The intake looked quite open and rectangular. I just took off the sharp edges

Re: SHA Dellorto fuel leak ?

ᴛᴇʀʀʏ ᴅᴇᴀɴ /

it's not that big of a deal, just a little extra work for us trying to help. the carb should not dribble. Do you have pictures of your intake mod?

Re: SHA Dellorto fuel leak ?

> the worst terry Wrote:

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

> it's not that big of a deal, just a little extra work for us trying to

> help. the carb should not dribble. Do you have pictures of your intake

> mod?

We can stick a fork in this thread and call it cooked and continue on the other one.

I now know this dribble is not normal but only occurs when the engine is running.

Thanks !!!

Re: SHA Dellorto fuel leak ?

Oh... and I’m afraid I didn’t take pics of how open the inlet window is. It is a new case and was opened up as it was.

Re: SHA Dellorto fuel leak ?

ᴛᴇʀʀʏ ᴅᴇᴀɴ /

the sharp edges on the inside?

the rotary valve on a Vespa motor works when the inside of the case seals against the crank lobe, adjusting the hole inside the cases can be detrimental if care isn't taken to make sure it's done right, it doesn't take much to goof it. it sounds to me like you may have broken that seal, or at least adjusted the intake timing enough that your getting gas out the carb and it's affecting your running.

what air filter are you using? can you get a video of the gas coming out of the carb and post it up somewhere?

Re: SHA Dellorto fuel leak ?

ᴛᴇʀʀʏ ᴅᴇᴀɴ /

haha dang, we typing at the same time

Re: SHA Dellorto fuel leak ?

> the worst terry Wrote:

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

> the sharp edges on the inside?

>

> the rotary valve on a Vespa motor works when the inside of the case

> seals against the crank lobe, adjusting the hole inside the cases can be

> detrimental if care isn't taken to make sure it's done right, it doesn't

> take much to goof it. it sounds to me like you may have broken that

> seal, or at least adjusted the intake timing enough that your getting

> gas out the carb and it's affecting your running.

>

> what air filter are you using? can you get a video of the gas coming out

> of the carb and post it up somewhere?

Thanks !!!

I’m very, very sure I didn’t brake or modify that seal. I just took off some casting flash and sharp edges deeper in.

I tried both of these (stock and aftermarket) to the same result

F250A11C-F01F-4A4C-B01C-E1B7B9D33B23.jpeg
F865E25A-1761-4D1C-B44F-075CB5825896.jpeg

(edited)

Re: SHA Dellorto fuel leak ?

ᴛᴇʀʀʏ ᴅᴇᴀɴ /

I reposted over in your other thread, let's continue there

Re: SHA Dellorto fuel leak ?

Absolutely. Much better there !

« Go to Topics — end of thread

Want to post in this forum? We'd love to have you join the discussion, but first:

Login or Create Account