150 to 166cc conversion

Hi mates.

Say, if I upgrade my px150 allstock with a "plug'n'play" pinasco 166 should I change gear ratios?

And regarding sitoplus for px, how come it's working on 80, 125 and 150cc the same way?

Do I need rejetting in this case?



It depend s how old the PX150 is , older models definately had 22 tooth clutchs which is perfect gearing for a simple bolt on kit , Pinasco 177 or any other ( except maybe Quattrini ) - the sitoplus question is in two parts. I will leave the first part to someone else but can tell you that if you bolt on a kit you will definately have to upjet your carb as a matter of urgency. The kit instructions may give a guide range for rejetting ??

my px was made in 94, so I guess in this case the change is advisable?

so, if i won't upjet the carb it may result in inadecuate mixture or something?

You will need to check the amount of cogs on your clutch , if it has 22 then there should be no need to upgear but if there are 21 then maybe it will need a new cog - not definately just maybe, try it first and then decide.

If you run your new kit with a carb jetted for a standard smaller cylinder then it will run weak and almost certainly cause a very quick seize in the cylinder. You can expect to change the main jet ( let us know whats in there at the moment ?) and your spark plug to a colder B7HS or even better a B8HS. Before fitting your kit its worth painting the cylinder and head with black cylinder or exhaust paint - this helps with heat dissipiation and can make the difference between seizing or not . All the parts you need are available from SiP.

If you have not already got the Pinasco kit , please note the kit is available as an alloy or cast iron kit - the alloy costs a little more but is my recommendation.