PX 125 Gearing

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Posts: 1
Joined: Tue Apr 02, 2019 6:52 pm
ebay user ID: Vespa_1966
Main scooter: Vespa PX 125 2015

Tue Apr 16, 2019 12:09 pm

Just bought a 2015 PX 125 ES with 700km on the clock. I have fitted a 166 Malossi kit, PM Tuning exhaust and a Dellorto 24mm Carb. After sorting out jetting issues (Stack - 130/BE3/118 main seems to run and idle fine however the gearing needs to be upgraded. Any ideas folks. Cosa clutch T5 4th Gear????

Scooter wont idle anything bigger than a 118 main jet.

Thanks Mike

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Joined: Tue Oct 25, 2011 9:50 pm
Main scooter: Lambretta
Location: Lanarkshire

Tue Apr 16, 2019 11:17 pm

Welcome aboard

Post your question in the Vespa section, idle should have nothing to do with the main.

As to the gearing is it revving out in top or won't it pull top?

T5 4th is usually recommended for P2 gearbox, not sure it would work with PX125.

An adult with more Vespa knowledge may help...
"Our dilemma is that we hate change and love it at the same time; what we really want is for things to remain the same but get better."

paul d
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Joined: Thu Jun 30, 2011 10:00 am
Main scooter: T5 172 Tv 240
Location: Galway Ireland

Fri Apr 19, 2019 9:39 am

The T5 fourth is the same as a px125 one I think. Using a clutch with more teeth is the easiest way to upgear your engine. I think a px125 has a 20 tooth clutch. A 21 tooth will give a 5% upgear. A 22 tooth clutch will fit but your scooter might not be powerful enough with only a pm exhaust and no other modifications. If it was me I'd buy an old style piaggio 21 tooth. An allrounder style engine is much more satisfying than one that only works well with a tailwind or downhill. Cosa clutches vary so much in quality that I'd only recommend them for someone who's experienced in fettling or has enough money to buy one of the expensive ones!

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Posts: 102
Joined: Sun Jan 13, 2013 10:50 pm
Main scooter: vespa t5

Fri Apr 19, 2019 2:29 pm

Agree with Paul as above. Only thing I would add is that If your current clutch is a good one, id consider buying just the 21t center cog. Less than a new clutch and if your current one works them why not use it. Personally I would put slightly stronger springs and honda cr80 plates in, and band it. But that's just me, I like to overkill.
Your main jet should not affect idle.
Is it a p200 type si24/24? if so, can I ask where you got it? I'm looking for one.

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Posts: 102
Joined: Sun Jan 13, 2013 10:50 pm
Main scooter: vespa t5

Fri Apr 19, 2019 2:33 pm

Sip part number 87470000 for reference

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