Some questions regarding my project

hi everyone

i have a cosa 125 VNR1T 1991, i have open up the motor and now i need someone with good knowledge for help me.


Cylinder kit - Polini Art. Nr. 14000800 or Malossi Art. Nr. 10030000, what is the best, i have the motor all open and don´t mind to work the transfers, timing change is not a problem too.


Crankcase - offcourse a racing one "cut crank", but when i search for tuning cranks for my cosa nothing appears, i think the px one will work but not 100% sure, and the longstroke crank what is the difference, need something special? can i use it with above cylinder kits? if possible, info me about the correct article number. the bearings are the original ones?


Clutch - I'm thinking in this kit, clutch plates Newfren Race Evo PX200/T5 Art. Nr. 93117000 is this a good clutch or should i buy another?


Carburator - original one is 20/20 with oil pump and electric choke, and i have one 24/24 somewhere in my garage, old one, no oil pump and manual choke, i prefer disable the oil pump because the new configuration will demand more oil, any chance to tune the oil pump? for the 24/24 original jet is fine or need bigger?


Gear - I love torque, speed is not my goal, it´s better leave it original or change some gear?primary?


Exhaust - I live in france and here the police looks more for the loudyness, someone told me that SITO is good exhaust for this purpose, but off course for my eyes its ugly, simonini, polini or malossi ones are much more loud? recomendation please?


Final question -  i will transplante this largeframe motor to a smallframe chassis a pk125 one, does someone have made this modification? what is better modify the chassis or cut the engine case block? if i cut the engine case i will need 2 pieces of silent rubber, the number 13 from this exploded view SIP don´t have it, does number 5 works?

anyway if someone tell me what is better i can start buying the goods.

i thanks in advance who can help me, forgive my english is not my mother language, and if can't understand ask me i will try to explain better


can someone help me with this?

i want to order the pieces, i already received the first order and need to make the second, so please someone look for my post, its only 5 minutes of your time.

i tried asking via email but the answer was not the correct one. they told me to ask here.

hope someone help me on this


Hi dude


i think the best would be that i answer you in more parts , this email is too long for me


let us beginn with the modifies for the engine in  pk 

are you shure to do this conversion ?

it´s really heavy to realise, did you know someone who made a conversion like this to tell you tricks or maybe help you ?

The thing is that the traverse is so different that you have to modifiy heavy the engine case and also the frame a lot.

It would be easier to make this with a px engine , but also difficult.


What about a bad pk engine ?? 

Basically the smallframe engine is better for heavy tuning - honestly !!!