Modern Vespa

Hello!!

I’m about to take the plunge and buy the Polini Original Box Exhaust for my PX 200 engine.

Is it plug and play, or do I need to change jets? I’m running a stock engine.

Thank you!

Yes you should definitely upjet for any better-breathing pipe. Haven't tried that one, but as a hunch I'd guess start 10-12 points up on the main jet and work back down, since it's still a box pipe. Maybe someone else who's used it can say otherwise

Upjet, yes, but as it's a plug and play on a stock engine I'd wager it's more like a sip road (based on my experience -- have employed both, and they have similar jetting needs) which asks for a MJ increase of 2 or 4. I'd say you could start with an increase of 6 and work down.

The idle mix will probably need to be richened up a bit too, maybe an eighth or a quarter turn.

Don't think it necessitates a bigger idle jet though.

(btw excellent choice Feruza -- the polini box is great. It's torquey, not revvy, really coming into its own in the 4000-7000 rpm range. Your stock setup won't be going above that anyways.)

That’s what I’m after, more torque a bit of extra power. The Polini seems to be well balanced for a stock setup, well made and with a pleasant noise.

Let’s see if someone can give advice on the required jets for this exhaust on a stock engine.

Start at 125 and you'll probably need 120 and 122 to hand for an autolube motor

I'll just say there's no harm starting high and working down. But there is harm starting too low. A stock P2 can dial in as high as a 125 with an SIP Road 2, even if others wind up lower, so why not start at 126-128 and work down as suggested? Couple of bucks to avoid a soft seize. I've been there.

What jet did you settle on? Where did you start? I'm getting ready to install a Polini box on my P200 too.

I have a 125 MJ in a Rally 200 stock motor, that maybe a good starting point for you.

Good luck with the black art of jetting 😎

Cgt75b.

is this that new one over on SIP?

if so, how does it perform and how does it sound?

Polini box has been out for a few years I think. FMP has done many videos on it, ex: SIP: https://www.sip-scootershop.com/en/product/racing-exhaust-polini_2002022

I have tentative plans to install it tomorrow; will be too wet and cold to do a test ride though.

ah. very cool. good to know. I'm a little behind the curve on new stuff. I have piles of old stuff that I've been cobbling together stuff with for ages. figured it was time to start spending a little dough on some updated gear and step into the modern era.

You answered my first question here like a year and a half ago. I wanted that old Vespa sound back after inheriting a Road 2 on a PX. Thank God I didn't go back to stock as planned!
Thanks for that.

The Polini sounds similar to the Road 2. I love it -- enough to go to considerable lengths to make it fit on 8's. Delicious on steep hill climbs.

Beats all the other boxes in power up to around 6000 revs, before the others catch up. Andre from SIP has five or so compared below on a dyno:

Re. The Polinibox sound, I can testify that it produces a nice, deep, muffled pop that of all the newfangled box exhausts is the closest to the original.

Which is great. There's none of that tinny sharpness you get with so many of the other boxes. It sounds like a Vespa should, only a bit louder.

I tried the polinibox on a DR177. Extremely disappointing. My mechanic guru played about with the timing to see if this could affect it, result was no. Its got plenty of torque lowdown and flies in third gear better than road 2.0, but fizzles out in top speed, couldnt get the speedo over 100 kmh. I put the road 2.0 back on and i can reach 110+ kmh indicated (top on gps was 65mph). Many have commented the same of the polini box on other threads, losing 6mph top end. My setup with 24mm is AC140 BE5 and 121 main jet. 50/120 pilot. With polinibox it was spot on with 118 mj, so its less juicy the polini. In summary, its great for local buzzing about and overtaking cars in the 45-50 mph zone, fizzles out at WOT in fourth. Mine sits in shed rusting having used it for two weeks. Couldnt get enough speed up for driving the 60mph dual carriageways to work. So jetting wise 2 to 4 pts up over standard IMO.

Did you ever measure the ID of the end pipe on the Polini BOX?? They revised it "silently" to a bigger one, to deal with top power and heat. The first ones came with a 17,5mm ID pipe and newer ones were 20mm. I replaced the pipe on one that I had and it did improve things...

Which box do you have? There are two models: 200.2018 (https://catalogue.polini.com/en/product.php?id_prodotto=160532) for 125cc/150cc and 200.2022 (https://catalogue.polini.com/en/product.php?id_prodotto=160533) for 200cc.

https://beedspeed.com/products/vespa-px125-150-166-177-180-super-polini-road-box-exhaust?currency=GBP&variant=39831725801658&utm_medium=cpc&utm_source=google&utm_campaign=Google%20Shopping&gclid=Cj0KCQiA8vSOBhCkARIsAGdp6RR_RbJz4ZF9fBZftJe2QzT_JtfDdDjzEd1MsACoO8lYkjuVYNUiKZQaAiFDEALw_wcB

I got it here, last year in fact. Its great around town and super zippy in the 50mph area but no top end on carriageways, it won't rev out like my road 2 where I hit gearing restrictions at 65mph GPS, I was getting 58mph with polini. Id stick it back on if i wasnt doing long distances as it pulls great and can fill front wheel lifting off the line from torque. If this is different pipe to what you are talking about? I'd ask you to check your top speed before putting on and then after with polini on and let you judge, i can only talk for my experience. I let friend drive the scoot so they could judge and the comments coming back weren't positive.

I shall head to my shed of parts tomorrow and measure . It was bought last year.
It certainly didn't arrive with the shiny finish as the photo depicted in polini stock photo. It had the finish of the p200 one placed in the link earlier in this thread.

I guess it depends on the RPM. My 225 tourer has a Polini Box and is geared pretty high (PX200 gearbox, 24T clutch, 63T primary, 36T 4th). It won't go above ~7200 RPM in 4th (a little over 75 mph on a good day). That's not a problem cos it keeps it reliable and comfortably for cruising long distances. The previous exhaust was a BGM BigBox v1 and the Polini was definitely an improvement.

It sounds like Polini Box is not suited to high revs, but it makes great power, at least to 7000/7200 RPM

It would be nice to know more about the motor used in that SIP exhaust comparison. Based on earlier videos, I think it has one of those Quattrini M1XL kits, which means big reed valves and some kind of aftermarket carb, plus souped up even more in this case with a P200 connecting rod with a 60 mm stroke. That would explain the "plug-and-play" 22-23 hp, but makes you wonder how relevant the results are for people who just want to throw an upgraded box exhaust on a mostly stock motor.

Yep, it looks like this kit https://www.sip-scootershop.com/en/product/racing-cylinder-quattrini-m1xl-11-172-cc_15046100.
Looks like a smart carb is being used since no need to change or even check the jetting.
Gets almost 15 horsepower @ 6000 rpm with a stock exhaust. That setup is doing around a 100% increase in hps from the stock 7.5 horsepower @ 5800 rpm.
The polini box in this video has an increase to 21 hps vs the stock exhaust of 15 hps or 40%.

What you both are saying jibes with the dyno graph from the SIP video. Take a look at that XL!

7hp more than the Polini at 7k.

is the 20mm outlet for the 200 polini box or 125/150?

You're right. I'm putting too much emphasis on the > 7000 RPM range, which for my gearing is almost flat out in 4th. The majority of my riding is most likely 4000-6000 RPM, which is probably why the scooter feels so good with the Polini Box. With my setup, I think that a SIP Road 3.0 would be quite interesting.

Do you know which motor spec. this test used? It's clearly a small block motor with a side draught carb, and from the other engine build videos, it appears to use a Quattrini cylinder kit and a crank with a longer conrod than stock.

Going back to the original poster and his stock p2, i have no doubts they will be happy with the polini because if you are trying to get something that sounds and looks like the original stock exhaust its very close. Its very easy to fit, I found it actually better fitting than a road 2. However, if you want more top speed, the road 2 looks similar to the original but it is nowhere near the original sound, they get fairly loud but top speed on standard will be superior IMO to the polini on his stock engine. Horses for courses.

Good eye! PX80 with a Quattrini M1XL cylinder. I forget the carb, but it isn't a SmartCarb.

There's a full (9 part) build of this engine on Youtube

FMP must have had his camera on auto-mic in that video. The Polini is quite a bit louder than the stock Piaggio.
Made my own quickie comparison between the Road 2 and the Polini. On my driveway, so couldn't rev it as I'd liked to. Neighbor was unloading a wheelchair across the street.

They're both just as loud. Tone is different.
Both on kitted px's.

What about the malossi power? I spoke with Matt at scooter mercado and when I was making my decision and explained him that I had cylinder kit etc he said that the Malossi favors the top end better. I am not saying one is better than the other but I think the Malossi must be considered.
Ultimately what I really think is that the riding style is what needs to be considered. Do you ride all the time above 7000 rpms? if not maybe Polini is great. Do you ride on the hwy on your way to work were everyone is going fast on the hwy? perhaps a high rev exhaust is better.

scooterist --

I'd read somewhere that the Malossi Power Classic Exhaust -- the box version for the 200 -- does favour the top end more than the Polinibox, but will definitely wake up the neighbours. The dynos for the Sip Road 3 meanwhile show that it hangs onto the power well into the high 7000s and will result in a similarly higher top speed, and it allegedly sounds OK. That to my mind would be my 2nd choice if I ever get a hankering for more top end power. Just hope that SIP sorted out that problem with the SIPRoads 1 and 2 where the inner wall was so inexpertly welded that it'd come loose after a couple thousand kms.

Meanwhile after much trial and error I've managed to arrive at a passable "goldilocks" solution for most real-world applications with the Polinibox and a Malossi 221 Sport setup (with the standard SI carb) by moderately lengthening the gearing: a 24 tooth DRT clutch gear, the standard PX200 gear stack, and 100/90-10 tires. It lengthens things 5-6% from stock and takes advantage of the Polini's bottom end torque. There's no need at all for a short 4th. End result is that it's fantastic for around town and back roads, and when hitting the highway it's possible to park it at 120km/h (75mph) / 6400 RPM, at 3/4 throttle. With no headwind at WOT it'll creep up to 130km/h / 7000 RPM.

This setup's sweet spot, to my mind, is cruising around the 100km/h mark. That's at relatively low RPMs, between 5000 and 6000, all day long. And it's got plenty of power left between 6000-6800 for overtaking.

So yeah: low end power + longer gearing = big smiles. For me at least. Better fuel economy too.

That's not to say it's slow as shit though -- here's a 0-100kmh test. Something just north of 10 seconds:
https://www.instagram.com/p/CVhwoA-oqVo/?utm_source=ig_web_copy_link

^^ Excellent review. I found that the exhaust boxes(no matter which one) gives me crazy low end torque, that includes the stock box. When I put the expansion chambers the high midrange and top end is crazy strong but I find a very weak spot on the gearing and the power band.

My problem (duplicated on two scooters) is that acceleration to 60 mph is lighting fast, I can reach 50 mph GPS in 9 seconds and 11 second to 60 sec but when I shift to 4th gear the rpms drops dramatically and the wind resistance makes the 210 Malossi kit to struggle to " catch" the high revs again to keep gaining speed. I will do over 70 mph but from 60 to 70+ takes forever mainly due to the gearing and the way the cylinder kit produces the power band.

Once you enter that sweet spot of high power band again you start piling up more top speed. I take it for what is worth but I personally feel very uncomfortable above 60 mph-65 mph (gps), it feels like I am tense and worried.

If I don't want to go faster than 60 mph the Malossi 210 sport with stock P200E proves to be a nice cruiser, you put no stress on the motor at that speed. I can't say the same thing on my PX150(166) which is screaming on the RPMS at the same speed.