150 5 port options please!

Hi guys, I have a 150 5 port (ScootRS) motor with 24 PWK carb and tuned exhaust.. Am going to put a Polini177 kit on soon... should I change the crank (& to what sort?)..Will the 24mm carb be alright (up-jet if needed)?? cheers for your help in anticipation....

Can you please tell me what difference putting the Malossi head on the Polini 177 kit will make? Is the Malossi head the 166 version? Also I forgot ot mention in an earlier post that my engine also runs a reed valve set-up... Cheer for you help...

The standard crank will take a decent amount of abuse to be fair, but if you have any doubts then I would go with a serie pro special lip longstroke with 1.5mm packing plate. Nicely suited to the Polini kit.

The 24 should be ok if you can upjet it far enough, I have never used one but there are jetting guides on the RS site i seem to remember?

The Grand Sport piston is definately an improvement over standard , but saying that the standard piston in the new kit is Asso Wercke I believe so should work pretty well - comes down to preference and budget I guess.

The Malossi 166 head is deemed by some to have a better combustion profile and as its got an O ring seal is less prone to blowing - I have to say that I have personally used Polini kits for many years and as long as its built properly and jetted correctly the heads are just fine. Some people blame any pre-ignition 'pinking' on the head and the head alone - I disagree but thats just my opinion.

Thanks for the info... I forgot to mention the motor is already running a reed valve too... does this make much difference to what I am doing? Using a long stroke crank will change the CCm too? should I use the Gran sport piston as mentioned on the Polini kit page here?