can a 125 casing be converted to a 200 on a vespa?

[OzOAP]

Can be done, I did a couple for Dave. Wouldn't dother though. Plenty of decent kits for 125 casings now days. Its a bit of work modding for 200 barrel and even more work to fit 200 crank.
A 200 crank can be modded to fit into 125 casings but ur very limited on inlet width.

hey Stirling, i thought it might be novel, down the road here a bit, to put one of these together. i think i understand what needs to happen, welding the ports up, machining the mouth, gasket face, a recess for the crank and drilling for the studs. is there anything else you found? would you do something differently? fit a ts1?
thanks!

I did the PTS1E on a T5 casing.

[tony]

can you expand on the stud configeration bit tony, i dont know anything about vespa small block engines.....infact the only thing i know about the big block is that it biggerr than the small block

Hi mate,. the restriction on the p200 motor (same on lambretta motor small or large block) is the stud config.
You can't get the area on one side. If you have a square or at least symmetrical config you can get better port size and angles. This is one reason why the smallframe motor is so tuneable. On one side of the 200 lamb casing for example the stud spacing is almost the same as the smallframe motor which has to only service around 135cc max usually. Its that port area thing again Nick

So if it were me.. I'd look at the standard motor and stroking it. That M1x kit looks pretty decent. The T5 motor had nice wide stud config.. best ever for a vespa.. just needed a longer stroke crank and barrel worked to suit.

[cezeta]

can you expand on the stud configeration bit tony, i dont know anything about vespa small block engines.....infact the only thing i know about the big block is that it biggerr than the small block

Hi mate,. the restriction on the p200 motor (same on lambretta motor small or large block) is the stud config.
You can't get the area on one side. If you have a square or at least symmetrical config you can get better port size and angles. This is one reason why the smallframe motor is so tuneable. On one side of the 200 lamb casing for example the stud spacing is almost the same as the smallframe motor which has to only service around 135cc max usually. Its that port area thing again Nick

So if it were me.. I'd look at the standard motor and stroking it. That M1x kit looks pretty decent. The T5 motor had nice wide stud config.. best ever for a vespa.. just needed a longer stroke crank and barrel worked to suit.

just bought a mk1 t5 to see what you mean, it has a molossi kit going on and a box pipe it will be my first lardy on the road, its taken me 20 odd years to be convinced so in for a penny in for a pound i bought the uglest one they made.

[tony]

Nick 'Torque' Cezeta... buys the reviest standard Vespa he can.....

[Diablo]

I was just about to say that Tony!
Not the ugliest though Nick surely that accolade must go to the Cosa.
One of my mates does say though that the MK1 T5 headset and square backend makes it the Austin Montego of the Vespa world

[cezeta]

Nick 'Torque' Cezeta... buys the reviest standard Vespa he can.....

well i had to give it a go, i can sell it on if i dont like it. kylie (mrs cezeta) had a t5 177 motor in her vespa and hated it so we swapped it out for a p2 lump which pulls well with her being 8 stone.

me and jigs (captain cruiser) used to live together with our girlfreinds and he would go everywhere two up flat out as his only transport. lasted well so they must be quite tuff to pull that great northern lump and his mrs.

my choices when buying the t5 were the t5, a cosa or a bajaj so im not shy of an ugly scooter. i went for the t5 as it had a disc conversion and because tony made me wonder what the fuss was all about with them.

we ll see, i may be converted.

[cezeta]

I was just about to say that Tony!
Not the ugliest though Nick surely that accolade must go to the Cosa.
One of my mates does say though that the MK1 T5 headset and square backend makes it the Austin Montego of the Vespa world

i ve always seen it as the xr3 of vespas but the montego is a better one. the cosa being the alegro estate

[tony]

The barrels are ace Nick.. for you and your preference a long stroke crank and maybe the malossi kit and a bit of work. I have a feeling the malossi has lower timings and so will lend itself to a longer stroke.. however ... is there a long stroke for these motors? I dont know.. I've see some stepped pin conversions done.
Anyway.. I use t5 barrels on my red 90ss.. here's what is possible.

[cezeta]

those transfers are the same overall size as a smallframe petrol tank.....im concerned about your carbon footprint

looks good, not the sort of thing ive currently got the motivation for hence why i bought a reliable vespa (which is having a molossi kit put on as we speak) and keeping the lambrettas in the garage for a bit. im a bit over having things in progress and writing off the series 1 shortly after finishing it made me dig a big hole and bury my tools in it.

have you got a thread running on the t5/smallframe conversion? id like to read about it if you have.

[tony]

Hi mate,. no.. I have done two of these motors, a rotary valve and now a case reed. But I did them both at least 6 years ago. I can send you some pics if you want. I wouldnt do another conversion as its a load of hassle and today we have amazing kits from falc/parma/polini etc. Its just not worthwhile anymore.