Scooterotica

This is my first foray into P range upgrading and tuning so im aftter some help.
I'm looking at building a balanced every day bike based around a small block P range engine that's capable of providing P2 or better performance and reliability.
So here goes
BGM 177 kit (I have their RT195 kit on a lambretta and like it)
60mm crank ( probably mazzucchelli)
SI 24 g T5 carb
P200 gearing
BGM box exhaust,

I have chosen the the BGM kit and exhaust as I have a RT kit matched up with a BGM clubman and they work well and make it easy to ride.

Not sure about the gearing or the carb choice.
I have read that using SI carbs with 60mm cranks can lead to failures.
I have also read that the SI24g carb is as good as the SI26mm.

I am thinking the same set up but with a phbh 28 carb Can't find many people who have them set up yet with some miles under there belt,but willing to give it a go.Gearing was going to leave it and see what it like

this kit doesn't seem to have much use yet, I'm sure someone will have a bit of info
Looking at the dyno graphs and the power it's outputting I figured taller gearing would suit it better.

what do they reccomend with the kit ,prob best to follow their advice on such matters

most (if not all) small block vespa kits will benefit from upping the clutch from a 21 to a 22 tooth sprocket (most wont pull the 23 of the 200) leave the rest of the gearbox "as is" and DO NOT put a p200 4th in it! malossi and polini large block kits recommend/use a t5/px125 4th gear or they die on their a$$. A sip banded cosa clutch with sip fast road springs and newfren plates
If using a crank with modified inlet duration they always seem to not run just quite right on an si carb so I've always found them better with a 28/30mm pwk or phbl
as for exhaust, i'm sorry, but no box exhaust will come anywhere near a decent expansion (and there are many many dyno charts to prove this)

Cheers Padge.
Might need to rethink my set up.

yer welcome Paul

I have a DRT 22t clutch gear & 65t primary combo with an otherwise standard px125 box in my quattrini m1xl... 1st & 2nd gear are still very short... even with the up-geared clutch & primary - so I would suggest fitting a longer 1st & 2nd cog to the 125 box.


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The one thing i would say is that the 24g T5 is not easy to set up correctly for a PX. The range of jets available is much smaller. You would be better off going with the 24/24 P200 carb

Simple and easy option...buy a P2 engine, sell your 125 engine, total outlay maybe £300. Job done.