Modern Vespa

Any ideas on WHÝ the smart people at Piaggio designed the heart shaped ´roof´ space above the jets? I mean they inténded it to be there like that.

Second question: A more spacious filter cover makes sense so I am fitting one but I am wondering if there is experience with that here and if any effect was noticed.

Third one: The T5, even though only 125 cc has a slightly higher, better flowing airfilter so surely it will be beneficial on the 200 too. Anyone tried this?

Here's my understanding that I once read somewhere…
When the filter is undrilled, air to both jet stacks must first flow through the small rectangular notch at the edge of the heart shaped cavity, i.e, it serves as an air flow brake to both jet stacks. PXs and maybe Ps (?) used this filter.

When holes are drilled over the jets, air flow bypasses the restriction. I believe the Cosa was originally designed to use a drilled filter, which is why you used to see the pre-drilled version listed at Euro parts suppliers as the Cosa replacement filter.

Why the restriction in the first place? Fuel economy? Reliability? Vehicle regulations? Emissions?

I dunno.

#2-i've done it and haven't noticed any performance differences...at least with a warmed over stock 200.

#3- I've done this as well. I didn't notice much of any performance gain either.

Thank you for sharing.
My take on it is that the ´roofed´ design is an additional dust/water stop.
Later on the Euro emission norms came into play and thus more accurate/stable fuel metering meaning the turbulence of the original design needed be deleted.
But... just my idea.

More volume, higher filter probably need accurate testing under road conditions and even thén. The air resistance is such that half a hp would be marginal gains only in top speed.

Drilling the filter makes it run leaner. This would have been for emissions, which, if already jetted correctly, would make the engine feel revvy and lively but as always with lean jetting, it feels great but has less pull, gets hot, goes slow.

Read that less rich a lot but don´t see that really.
Also leaning the mixture to meet emission can be done by rejetting.

Concerning the higher T5 filter and a larger volume cover, those WILL have a positive effect on the air flow. Less sure is whether it improves máx as the intake may very well be the bottle neck.
The ham question is what it will do to the torque/power. I think nothing but that it will positively affect responsiveness.

It might be challenging to fit the taller PX airbox cover over the top of a T5 air filter when using a P series carb. The reason being is that the P carb is taller than a T5 carb. You might have to do some custom welding to the cover to make it all fit. Option B is to open up a can of worms and use a T5 carb.

oh my

I´ll stick with the 24/24 and drop the larger lid over the drilled original filter.

The heart definitely acts as an air brake. It's also an air flow stabilizer (AC's not directly exposed to air flow to the bore/changes in air pressure).

Bigger air box cover helps for a more harmonious air flow. It will not give you more power but it won't hurt. Generally they're used with a venturi to provide more space above them, but I like how it feels/sounds with a filter.

Many have tried the T5 filter. It isn't designed for that carb. Barely open throttle becomes difficult to sort out (bore too tall).

Be careful adding complications to your bike for minimal power gains.
Jetting is complicated business! Even drilling the filter can do damage if you don't jet to compensate.
In my anecdotal experiences, reducing the air corrector by at least 10 is enough but your bike is different.

Very astute, all euro 3 and euro 4 Vespas do have reduced jetting, as well as the drilled filter. And all of them rev nice, sound nice but perform terrible.
What are you trying to achieve?

On my Rally I'm running a 24/24G with the T5 airfilter and it all fits nicely under the stock airbox cover. the shorter carb exactly offsets the taller filter.

When i mean can of worms, i mean the jetting will be different than a 24/24E. A 24/24E combined with a T5 filter might take some welding on the tall filter cover lid to make it seal up. And it always seems like any jetting thread here at MV is at least 3 pages long.

Thanks for sharing all of the experience.

I would like my P200E DN to be nicely responsive on the throttle and have a bit more grunt.
After carefully running after the engine refurb want to fit a Polini Road Box.

Thinking of leaving the 55/160 idle jets, but go from 116 to 120 main and from 160 to 150 air. May fit that latter as suggested from go as richer is also more lubrication and I do live in proper mountainous countryside.
Will fit the larger lid too.

Once you've changed the exhaust. Up jet to 140 air corrector, 55/140 idle and adjust the main down from 130, until steady 1/3 throttle runs clean.
Will pull up hill like you've never felt.

I tried SIP T5 air filter with Polini carb box cover and SI 24/24. With alot help of Jack221 about jetting in the end I discard T5 filter but stay with Polini cover. With drilled original filter it was much easier to jet it right.

Thanks Jack221 that is indeed the aim. You don´t need (want) to any faster than standard top speed over here. Just better uphill grunt. The latter is exactly what lets the revvy modern 4Ts down. Revs are no substitute for 2T torque.

The visit to PuraVespa was a NoShow. Were supposed to be open, had hung the ´abierto´ sign up but... Thus called them and they first let it ring. Second call half an hour later phone was disconnected
As the visit was just an end point for a great ride with charming no harm done.
Does make me doubt internet ordering from them

Just curious; why 140 and not the same ratio with 160?

Fitted the 150 air. Left rest stock.

First running it in and best change as little as possible. Will do 3 tanks before the Polini and rejetting.

Not yet fitted the large lid. Same reason.

Just ordered a new lid gasket as the current one is getting too brittle for my taste.