Modern Vespa

So my scooter smell like gasoline every time I stop on a red light and its really frustrating because most of my riding is in city and I don't like leaving a trail of gas smell behind me , I have replaced oil rings, pistons , exhaust,also tried the malossi O2 ECU ,the smell is exhaust smell and a little bit of burned oil smell,I checked no oil or coolant leak,maybe it's faulty ECU since its fuel injectors.
Also the scooter has 125000km if that could help identifying the problem [/img]

Pull the spark plug. Does it look black and fouled? If ok, move on the injector. Fire it up and check the spray pattern.

If I'm reading correctly, you've just replaced the exhaust?

A new exhaust will always smell for a while, until the various volatile compounds are burned off.

You say it smells like gasoline, but further on you say the smell is exhaust smell.
These are 2 very distinct smells.

So can you clarify what it is smelling like? Is it gasoline (unburned vaporized fuel) or exhaust smell (the old exhaust smell before modern exhaust treatment)

Is the fuel economy worse than or about the same as it was before you noticed the smell?

[quote="PeterCC"]
You say it smells like gasoline, but further on you say the smell is exhaust smell.
These are 2 very distinct smells.

So can you clarify what it is smelling like? Is it gasoline (unburned vaporized fuel) or exhaust smell (the old exhaust smell before modern exhaust treatment)
[/quote

It does smell like exhaust fumes a really heavy exhaust fumes I only smell it when I stop and brake from fast speed tho

The mpg is the same

Sorry for delayed response everyone I didnt receive a notify of a response on my email

So it is exhaust fumes.

What Evo 250 is it? I expect an IE Euro 3 with lambda sensor and kat?

If that is the case then logically I would expect or the lambda sensor or the kat do not work.

Can you tell us a bit more on the origin of the issue?
It ran 125.000km.
Did you do that 125.000km?
When did you start noticing the smell?

I changed the lambda probe two times and the issue was still there i aslo tested the lambda that on the scoooter right now and its good,
I think the issue started after i ran the scooter without the oil retaining ring (the bottom one) for couple thousand kilometers, but snice then i changed the cylinder and the piston,i bought the scooter used at 90k but this issue started in the last after the 110k

Also i remember that i did play with the idle screw ,which i was a post that was saying that worns of playing with the idle screw because that it changes the ecu settings

I see. Meanwhile you replaced both the lambda sensor and the exhaust and that did not solve the issue.

You bought the scooter at 90k.
The issue started from roughly 110k onwards.
So you did appr 20k km without the issue.

I read you replaced a lot of parts. Why did you do all that?
I understand the smell issue was not the reason to start replacing things.

Buying it used at 90k was kind of a project to fix rebuild allthe parts so i can be sure that the scooter won't break on road,at first i was running the 250 hpe head but the fuel mileage was so bad that i went back to the original head

You saw it as a project but basically there was nothing wrong with it?

Tbh the torks were leaking a little bit a,engine wise nothing but i noticed q little bit wear on the rocker arms ,also 90k on 1 cylinder engine is pretty high tbh