Have been following the thread Help deciding on how to kit my 50 special by Tyke and i'm in a similar situation. My pk 50 xl is standard and out of the scoot. I'm going for a fairly mild set up but i'm abit stuck on some thinks/ parts to go for. First of all i've never stripped down a vespa engine before but i'm willing to learn and get stuck in. The set up i'm looking at doing: I've got a polini 110 kit off H on here and a polini exhaust also off H. I need to get a manifold for this and a 19/19 carb. I'm looking at splitting the cases myself and changing seals and bearings but these are the things i'm stuck on What primary ratio for the gears is best for me to get? Is it best for me to change the crank for a longer stroke one or a race crank? Crank at moment is a 43mm. What clutch is best to get or would just a race kit be any good for the clutch i've got? If anyone can help please.
The 102/ 115 kits need to use the 43mm stroke cranks, you could either buy a new crank or have you exsisting one modified to Polini's instruction and rebuilt with new bearings etc, up to you really but a new one is likely cheaper and less hassle. Gearing I'd use 24/72 ratio and clutch a good quality 3 plate like Surflex will be ample using a Polini spring. Another option on your carb and manifold could be the 20/20L as used on the ETS and some Motovespas.
Black Widdas S.C. - Taking idiocy seriously since 1999.
Thanks, i've just written down about the primary ratio set up and the option of 20/20l carb and manifold. As regards to the clutch, is this 3 plate a clutch kit. I could get my hands on a Surflex 4 plate race clutch kit, is this ok or not suitable with set up ?
For me a 4 plate is probably overkill but no reason as to why you couldn't use one. I think most 3 plates just come with the plates themselves rather than a full kit but I've not had a look in a while.