rb 225 or 250 your Opinion

[odd mod squad]

hello all

whats the best the 225 or 250 pros and cons
i was thinking of building a rb 250 for my new project

all the best

[deany]

not bored of your ferrari already Steve??

[tony]

there's a write up in scootering this month on the 250.

[corrado]

Cons are that you need to have the crankcase mouth bored out to accept the spigot of the 250 thus rendering it useless to anything smaller than 250.

[Train Driver]

When i looked into a rapido 250 i was told apart from vibrating more (keep revs below 6500) they also run hotter, can anyone running one confirm this

[tony]

I would say that you are getting fairly close to the cylinder studs and so yes you may suffer from heat as at those points the cylinder wall is thin. They may of tried to compensate with more metal around the studs (i'm not sure) but whatever you do this has to be the 'weak area' of the large bore kits.

[sean brady scooters]

i dont really actually know exactly how relavant this is as yet but ,on all cast lambo barells the studs are exposed...to cool air.
this is so on all std vespas.

on most (if not all)ally kits for lambos they are inside,and so Not exposed to cool air.
while again on vespa kits wether cast or ally they are still exposed.
could this make a difference.....?

[tony]

so you are saying the orig cast iron barrels have exposed studs but the new designed ones they are enclosed.

[sean brady scooters]

yes tony.

[tony]

i see.. interesting. malossi 172 t5 kit has exposed studs tho. But i'm reckoning it could be to do with more metal for anti seize.. or port angle maybe.