Which racing kit its better?

I have problem, im planning rebiuld my deadth engine PX 125EFL
Allways drive in the city sometimes toruirng.

First concept:
- racing longstroke crank Mazzuchcelli 
- polini 177 witch gasket 1.5mm
- carb si 24/24
- geraing malossi 23/64 or 21/68
but i heard longstroke its good - this crank don't like high rpm

Next concept:
- racing crank Mazzucchelli
- Polini 177
- SI 24/24 
- gearing 23/65 or malossi 23/64

Next cencept
- racing crank Mazzucchelli
- Malossi 166
- gearing 23/65 or malossi 23/64 or 21/68

Exhaust LeoVinci or Sito + or Simonni racing (maybe next year PM or JL)

I have question which racing kits (Malossi 166 or Polinii 177) its better for me.
I know DR 177 its weak to me.
Now i had DR 177, orginal crank, carb SI24/24, malossi 23/64, Sito +.


Sounds really good idea! Yes, its too much money! But, I just don’t have enough skills to boost up the engine myself. That’s why I prefer buying all new engine. I’m also going to sell the old one to my friend who is in need of an engine. Thanks for the info about the problems in fitting the engine, because I couldn’t believe it won’t fit… I let you know if I can make it! Thanks and good luck!

I used to have DR 177cc kit and I liked it. It had enough power for me. But, now I planned to buy a totally new 200cc engine! I really don’t know about the other cylinder-kits?

New engine PX 200 Lusso its very expensive for me :(
I planning fit on to my engine PX 125 - polinni 177, racing crank normal stroke, carb 24/24 with autolub, gearing from Cosa 200 23/65, exhaust leoVinci mayby good combination :)


I'd keep it simple.


Polini,Mazz crank,Simonini and perhaps a Cosa 22 tooth clutch.


The Malossi is a fine kit but I find the porting aggressive for anything other than a full on screamer.