Vespa Polini 210, bgm PRO 60mm, Dellorto SI26 - Tuning test engine - Part 1

With the appearance of the Polini 210, a dream has come true for many scooter riders.

Proven Polini torque in an aluminum dress from the speed basement with little effort. On the first "test engine" with a stroke of 57mm, this assumption was consistently confirmed.

Polini has recently started offering other interesting toys to increase performance and, above all, to increase driving pleasure. In addition to the already available Intake funnel for the original SI carburetor, Polini announced the appearance of a new cylinder specially designed for a 60mm stroke along with a matching 60mm stroke crankshaft, so a Polini 221.

Inspired by these developments, we decided to build a complete engine for test purposes. First with the 210 Polini, this will give way to the big brother that will hopefully be available soon.

So we first drag the following toys to our test stand, or first of all to the workshop for assembly.

Cylinder kit Polini 210, cylinder head MMW and Worb5, intake manifold Polini for SI carburetor, 26mm SI carburetor and a crankshaft bgm PRO 60mm stroke.

We take a closer look at all parts and prepare everything for installation.

First consideration is the motor housing, this is where all the toys will move in later.

New PX200 motor housings are currently only available from Malossi. Except for the distribution channel, nothing has changed on the motor housing.

We pay special attention to the rotary valve inlet. In order not to obstruct the fast-flowing fresh gases there too much, we remove the factory-made burrs and edges. Furthermore, the inlet will not be revised.

At the heart of the engine, we use the tried and tested BGM crankshaft. Optimal intake control angles will help our test engine run smoothly over a wide speed range.

The BGM crankshaft also offers the option of installing an FPM shaft sealing ring with a dust lip on the alternator side thanks to a larger sealing surface on the alternator cone. Compared to the usual shaft seals made of NBR, the FPM shaft seals a significantly higher shelf life.

Next, let's look at the “Polini Funnel” ...