Modern Vespa

OK, id like to know if there are any simple tricks for squeezing a few more MPH out of a small frame without cylinder kits. So on a standard PX125 you can simply bolt on a sip road 2.0 or if you are complete masochist and like your ears deafened, a sito plus. I reckon this gives you about 1bhp more than standard. So when my px was standard, the road 2.0 gave me an increase in 4 mph gps. Then there was the air filter mod, removing the heart shape over jets, claimed on dynos to give you 0.5 hp extra. This also improved acceleration and gave an extra 1mph. These are little top end boosts for little money.

So on a small frame, are there any cheap tricks you can do to get a few more MPH. I have standard 20mm delorto SHBC L carb, standard piaggio pipe and as standard an XL motovespa 75cc barrel. I have reached 48.5mph max on GPS. My aim is to hit 50mph so thinking a cheap mod will make this reality. So exhaust i can get hold of easy in the UK is the 125 version sito plus (yep, my exhaust manifold is the 125 size, dont ask me why but it is. Its cheap but likely will fall apart after 18months. There is the BGM Pro for pk125/pk75xl. https://www.scooter-center.com/en/exhaust-bgm-pro-bigbox-touring-pk-vespa-pk125-s/xl/xl2/ets-motovespa-pk75-s/xl/junior-bgm1125pk but located in germany and bloody expensive when shipping and customs duty applied. Not available anywhere in uk. Then there are the leovince banana pipes too, dont know anything about these. Anybody know about air filter types too? Can change in filters squeeze a bit more oomph? Im not looking for kitting as its a local run about scoot and have a px177 for hacking about on. I want to keep engine standard and reliable and just have reversible bolt ons/mods. Thanks in advance.

If you are stuck on keeping the pk75xl try a free flowing exhaust and maybe a light weight wheel in the rear, the SIP saves 1 or 1.2lbs of rotational mass. You can try a free flowing air filter, the stock carb location under the seat is very restricted. I had a shop gutting out the inside of the exhaust box and re-welding it, it was barely a little louder than stock.

Ah, finally someone brings up my favorite part about SIP's tubeless wheels!

What do you consider simple?...you could break out a dremel and start changing the cylinder's port timings. If you really want to hit that 50mph barrier for cheap, eat a few extra pies and find the steepest downhill you can find. Infinity and beyond awaits you!

Can't do the eat pies mod as I'm gluten intolerant lol.

I brought this up about the Pinasco split tubeless rims I installed a few years ago and got seriously flamed for it by people who eventually rage quit NSM (maybe MV entirely). I think that everyone was suitably traumatized to Never Speak of It Again.

It's not about power, it's about power to weight ratio! Go superleggera. Empty out the glove box. Take out all but a quart of fuel. Take extra keys off the key ring. Empty your pockets. Remember every once counts. Pump up the tires (less rolling resistance). The best part is all of this is free! Unless you buy a Porsche. They charge you more for a stripped down "club" car.

I too am in the same boat. I have a mostly stock premavera 125 with polini cp21 carb and 12v electronic ignition. Was wondering if I bolt on a Polini snail (up jet main) would that get me to 50mph? I seem to max out around 45.

This is the same thing as you my friend. I want some helpful advice, such as will an exhaust change, just push it to 50 and maybe a little bit more without mullering it down the kit route or chiseling bits off of it. It is in my eyes a vintage gem, hard to find in this country, 1987 xl75 motovespa that has been carefully looked after for its whole life in barcelona spain and i dont want to f*** it up and go down the bottomless pit of the kitting route and the pitfalls that come with this. I considered kitting but when i read what goes into it to reach a few mph over what im getting its not worth the money. e.g. the polini 102 and pipe and uprated crank and labour to reach 80kmh is what im nearly getting already with the 75. But if i can get a few mph with a change of pipe, thats my aim.

So, for example, i could ask, has anybody put a sito plus on a smallie and seen a few mph extra? This is the sort of question i would like answering. Im surprised your primmy doesnt go above 50, i though they were good for more than 50. Drove one I borrowed years back and it was quicker than my v100 and that always went off the 60 clock.

Well, im 12 stone 7lbs so maybe i need to cut back on the sweets. My tyre pressures are good and i have new s1 on rear. I dont carry anything in my glove box; they are plastic on a PK XL and delicate (no longer available so dont want to bust it) but i do have spare tyre under left side panel door. The thing is the Pk is a very light scooter as it is. It catches me by surprise about how flighty it can be in side winds. Always though the PX was like being in possession of a sail in wind, but a PK is very light. You can easily lift the front end up like a bicycle.

Ride naked!

That Hollywood gem never gets old.

So has nobody tried on a small frame
A polini snail?
BGM Big Box
Sito Plus
Leovince

Please share if you have and what you gained as no answers coming forward, thank you.

I have no experience with a PK 75. Keep in mind that 99% of us here at some point wanted and hoped to eke out just a few more MPH from our scooters with a simple inexpensive "whatever" bolt-on to the engine. Let me know if you come up with one, because anytime i want to add just a few more MPH it's at least another $500.

Leo Vince makes a nice pipe for the PK. I ran it on mine for a while, then modified it to put in my 50S w/ 125 motor and it does add some power, though louder than stock.

My PK50xl2 w/ DR70 kit and 19 carb did 50 or more when it had this pipe on.

Pretty good, is that 50mph GPS?

Ummm....

no, but definitely faster than before the swap.

Well ive ordered a BGM Bigbox Pro for the 75XL


So I shall let you know if it makes any difference to top end.https://beedspeed.com/products/vespa-pk125-exhaust-bgm-pro-big-box-s-x-xl2-ets-motovespa-pk75-s-xl-junior

Don't forget to up your jetting when you install it!

yep, Jets are about to be ordered too. Will only need 1 or 2 pts up as its standard 75 barrel, not a kit. BGM state 2 to 4 pts up but 4 pts is for 130 kits etc. With a tailwind on saturday hit 50.9 mph on GPS then 46mph in the other direction. Ive had 48.5 mph gps with no wind so hopefully the BGM will push me over the 50mph. However, when i changed my road 2.0 on my 177 to a polini thinking it would be better, it was 6mph slower so will wait and see and report back. Had the speedo cable and worm drive sorted out saturday too, no more speedo indicator flying about, interestingly the most fairly accurate speedo ive had. Its only 2.5kmh out against GPS, unlike my PX which is around 9kmh overread

Have you ever looked at the base setup of your motor? e.g. Port matching, Port timings, ignition timing, and squish?

Those can all be tweaked to improve performance noticeably, and that's before we even talk about O-Tuning (modifying the stock components to improve performance).

A lot of performance depends on how much work (and risk) you're looking to take on, but these motors all came from the factory with incredibly sloppy base setups, e.g. P200's shipped with ~3mm of squish when 1.2mm is closer to the mark (less for high-performance motors).

I'm not into chiselling bits on my scooters as I like to keep them reversible and original as I can .I'm happy to bolt on a kit etc but not mod an engine in such way it's irreversible. For example my px125 did about 58mph top speed on a good day , now I always get 64 and Rev out. I can put it back to 125 to sell for learner drivers and engine not touched. If I wanted to reach 70 80 I would buy a gts or a motorcycle .

So my buddy up road stuck a bgm pro bigbox 75 125 exhaust on the pk75xl and its upped its speed to just under 52mph. Pretty good for standard 75cc barrel. Its got bags of torque more pull and a higher pitch than standard. Drinks more fuel and up jetted on 20mm carb 2 pts to 78 . Great pipe for smallframe and allows me to retain the unique pk spare wheel feature under side panel door. The best thing now is no vibration in plastic toolbox and headset and side panel doors. Got from beedspeed after 2 days of order and cheapish at 119 quid including postage.