Modern Vespa

Hi all just picked up a vespa px125 and love it. The last time I had one was 30 years ago. Was wondering how to get a bit more get up and go without spending too much. Would a perfirnance exhaust and different jets and airfilter be any good? Dont have the funds to change cylinder head , crankshaft etc etc.

Rgds chimo

Yep get a SIP Road exhaust and upjet. No real speed improvement but much more torque. Btw post in Not So Modern for PX related stuff.

Yep, what Bobo said. I just did that to a 2012 PX150 and it makes a world of difference.

It's slightly louder and more 'lumpy' though, but the performance increase is there.

Buy a few jets, start big and work your way down. I don't think you'll need a new air filter.

You can also get a cheap 150cc stock cylinder and toss it on there.

EBay has a bunch of 5-port LML cylinders.

So:
150 cylinder LML or used
Sip road
Upset
20/20 carb if it doesn't already have one.

Thank all for your advice. Whst jets ned changing? Im not familiar with carbs and jets.

You need to put in a bigger main jet. Have a look at this link. It's for a rebuild of your carburetor but has good photos of all the different jets in your carb.

http://www.vespamaintenance.com/fuels.html

The main jet is a cinch to change. It takes literally 5 minutes. Remove air cleaner (Philips head) then main jet stack. Pull the jet off the bottom of the stack (force fit), replace it with new jet then reassemble. Very hard to go wrong. Don't over tighten. 😀

Apart from main jet do I need to change any other jets? Also ive heard people fdrilling holes in the air filter to let more air in.

I just changed the main. You can drill the filter but I just bought a pre drilled one. Not expensive.

Im going to get a sip road exhaust, drill the air filter and get some jets.
What size jets shold I get? Standard I think is 96.

Dunno about a 125 but on my 200 I went from a 118 to 125. As Staceman said, you have to experiment to find the right one.

I've got a 150 so it won't be the same either. But I tried 106, 104, 102 before settling on 100.

And I did drill the air filter, a 7mm hole and a 5 mm hole in the "love heart". Dunno if it made a difference though, I didn't test it in stages.

And a correction when it comes to the air filter removal: The air box has Philips head screws, then you need a flat driver for the actual filter and the jet. But it's a piece of cake to change the jets. The only hassle (that's widely reported on this forum) is the exhaust bolt not lining up with the captive nut. I overcame that by bending the tabs on the exhaust with a mallet.

[quote="Bobo"]Dunno about a 125 but on my 200 I went from a 118 to 125. As Staceman said, you have to experiment to find the right one.[/quote

Hi Bobo, out of curiosity? After replacing the main jet. Do you need to fiddle with the timing as well?
Thank you

No didn't fiddle with timing. Simple exhaust swap and bigger main.

How do I find out which carb I have. All I can see on the cover is numbers and no name.

Take the cover off and look at the carb. There will be a number right under the throttle slide arm.

Getting a cheap LML 150cc cylinder would be worth the cost in my opinion. Someone probably has one on here used for a few bucks!

it should be stamped in like this...

Hi it might be worth stating the year of your px as different years may benefit from different options
george

A SIP Road pipe paired with a Polini velocity/vortex system (about $50USD) is a *great* inexpensive way to get some more oomph without putting a major dent in the wallet. Of course you will need to upjet the main and possibly the idle jet as well.

What is a pollinivelociy vortexystem? I was on sip scooter shop website and they do main jet kits but I cant figure out what kit I need. My carb is a spaco si 20 20 d. I havd emailed them but hav nt heard back. Is the sip road 2 better thana revolver exhaust?

It's basically a velocity stack.
I believe it's a copy of what Al Hot Rod Scooters developed with his Vortex carb setup.
Pinasco does one called the VRX and abither Italian shop is doing something similar.

Polini
http://www.scooter-speed.com/products.php?986

Pinasco
http://tinyurl.com/qjehk3m