I initially wanted to write a review solely about this bad boy above, the Malossi Sport 70cc. One of the best selling 70cc cylinders ever made. It is cheap, long lasting, powerful and available for pretty much every scooter model on the planet. However, during my research I stumbled over a great blog that had not only better test equipment (Dyno!) than me, but also reviewed its main competitors from Polini and Stage6. Therefore I here present the 70cc Sport Cylinder Review out there, featuring the Malossi Sport 70cc, the Polini Sport 70cc, the Stage6 Streetrace 70cc and the Stage6 Sport Pro 70cc!
Before getting into the nitty gritty let’s have a look at each of them individually:
70cc Sport Cylinder Kit Review
Stage6 Streetrace 70cc Cylinder Kit
The Stage6 Streetrace 70cc is a cast iron cylinder with 8 transfer ports (Piaggio) and a two windowed piston with two piston rings. (Don’t worry if you don’t understand all this. TuningMatters.com will have an article about the difference of one and two piston rings and more available soon.) The liquid cooled model is available at about 130€ (not sure if there is an air cooled model out there).
Stage6 Sport Pro 70cc Cylinder Kit
The Stage6 Sport Pro 70cc is an aluminium cylinder with 7 transfer ports (Piaggio) and a non windowed (very shirt piston skirt) piston with one piston ring. The liquid cooled model is available at about 150€ whereas the air cooled one set you only 120€ back.
Malossi Sport 70cc Cylinder Kit
The Malossi Sport 70cc is a cast iron cylinder with 8 transfer ports (Piaggio) and a single windowed piston with two piston rings. The liquid cooled model is available at about 150€. The air cooled version should again be about 30€ less.
Polini Sport 70cc Cylinder Kit
The last of the bunch is the Polini Sport 70cc. A cast iron cylinder with 8 transfer ports (Piaggio) and a cut out piston skirt piston with two piston rings. It is the only modular cylinder (cylinder head consists of two separate pieces) of them all which also makes it the most expensive one. At 200€ for the liquid cooled version it is most likely not your first choice but if you run an air cooled model it becomes interesting at 130€.
So what does all this mean?
Feature wise the Stage6 Streetrace and the Malossi Sport are similar. Iron cast, two piston rings and not many bells and whistles is what you want from a wallet friendly “eco” sport cylinder kit. Perfectly fine to be used with the original carburator (increase the main jet by about 5-10%) and most of the original pots (engine revenue will increase by about 1500 rpm for all of those cylinders).
Standing out of the crowd are the Polini Sport and the Stage6 Sport Pro. The Polini unfortunately stands out for a bad reason. At 200€ it is tremendously over priced, especially when you look at the poor feature set. With a target revenue of only a few thousand rpm more than the original cylinder the thermal advantages do not justify the increased cost. The air cooled version however, should stay in the race since the high cost do not apply here.
The Stage6 Sport Pro screams racing with single piston ring piston and its aluminium nikasil cylinder. At 150€ this one is basically a no brainer and definitely best value.
The nitty-gritty
As mentioned earlier I found a Dyno test of these 4 cylinders on another blog and because stealing is bad m’kay I will simply forward you from here to their blog. However, as expected the Stage6 Sport Pro outperformed all other cylinders in the test. Surprisingly the Stage6 Streetrace performs nearly equally good as his bigger brother (some might say the racing piston and aluminium nikasil is more of a marketing strategy…). The Malossi and Polini perform well too but at a much narrower rpm band which means less power at higher speeds.
Read all about the Dyno test at the fantastic PedParts Blog right here.
What Cylinder kit do you ride? Are you about to buy one and have questions? Let me know in the comments or post in the forums and I will absolutely get back to you!