O-tuning Olivier's px200

[fastfrog]

Hi stage tuning freaks! here is a new thread about what german people call o-tuning: standard top end, crank, ignition and lots of appaloosas right out of it.....

PX standard barrel is a crap, 9,5 hp out of the box, seize and pinging all the time: a tuner nightmare....

Olivier, main moderator of scootentole (bigger french vespa-lambretta forum) told me: hey FF Why don't you do me a mild tuning with a bit of extra power and revs? No need to ask twice Frog to get ready with his cutting tools....

The project is:
E:175°
T:120°
I: 178° with 123°(btdc)-55° light flowing. overlap:3°
Lets start by inlet: 123°-55°
Sip road, SI24 E or G, lightened flywheel.

Engine is a motovespa (motoplat ignition) PX200 seized but in a relatively good state:



piston before its one way ticket to the bin:





barrel needs a reboring or a change:



inlet in progress:





an old barrel of mine in a better state: everything is small, badly build and rough...


let's begin the moviluty cure:





after a few in-out in-out:











boost port:







almost finished:







next step: exhaust and crank....

[ducksta]

spot on

[fastfrog]

timing with a std crank and 0,2mm gasket:
119/164°
with a 0,8mm base gasket:
123/167,5°
sounds better like this...

[225worb]

Yep I can see where your going with it..
Ralph saxleby use to do a standard p200 setup BUT TUNED of course and would guarantee 80mph +
oh an I think he used a leovinci pipe too but everything else as piaggio intended
There was a girl in the local club who had one done and it was pretty damn quick....

[mick1]

What piston you using and are you altering it ?

[fastfrog]

I'll take my previous o-tuning GS piston. ready to fit and still in a good shape.
inlet timing with its motovespa crank is quite unusual:
105° btdc/75° btdc 180° but shifted to the retard: Don't like this at all: too much blow-back and unecessary timing for an engine that won't rev beyond 8000....
timing with a std italian crank:
117°/53°



pics of my own o-tunig 200 posted in the "welcome" section some times ago: This is a more tuned engine with bigger ports and timing:

[ducksta]

wish my dentist had your skills

[fastfrog]

he's only nazi?

[sean brady scooters]

loving those crank mods ,nice work

[vespaloco]

Really interested in seeing this go.Anything that would pass the Spanish MOT and hopefully cost effective.
Always like to see standard stuff reused.