msk_motori

In context I bought the engine setup almost the same way it is. The primary was 2.34 (29/68) and when I rebuild it, I could not pull up 4th gear. I could only get up to 70km/h at straight. Then I bought pinion gear from DRT with 27 teeth, which brings my ratio to 2.52 (27/68) and with that I can pull up 4th gear better up to 85km/h. I know it is not great but it is closer to 2.56 as you can see below. 27/69 - 2.56 27/68 - 2.52 24/61 - 2.54 = original primavera About the timings. It would be nice to do a spacer, but I can´t because something was already done to exhaust by someone. I also made a portmap to check. Measured Trasfer to deck - 42mm Transfer - 115,5° Exhaust to deck - 30mm Exhaust - 177,1° Exhaust chordal - 34,5mm Exhaust to bore - 60% Piston below deck - 0.5mm Squish 1mm So in my case I would need to mill/bore/don´t know the word the transfer inside to get 125°. Also I would need to keep same port angle when doing. Also I thought about one place I might be losing power. It is the inlet to casings on the rotary pad. I did not resized it and kept it standart (width 12.5mm, height 23.3mm) And I don´t remember where I saw it and if it is true, but aparently PK XL casing have smaller opening and I have a V5X2M type which is I believe PK XL elestart and PK 50N casing. Do you think that this might be a limitation also? Anyway, thank you for helping

First of all, Hi I´m at this forum new. I´m speaking Czech and English and I´ve turned to this forum, because I already saw a lots of good stuff here and because in my country there is not much people upgrading Vespas. This summer I build a Polini 133 cast iron and I´m not impressed how the bike is running. Max speed by GPS was 85km/h and normal running speed was around 70km/h. I was expecting more from it and because I made a mistake with a o-ring when building this engine, I have it apart again to fix it. And I was thinking what more to do to maximaze the efficiency. Setup: Polini 133 (115°/175°) with original size base ports Piaggio 51/97 PK 20/20 cut crank Dellorto Phbl 24 29/68 with DRT z27 pinion (final ratio 2.52) Proma exhaust original Piaggio 4 plate clutch with single Malossi hard spring original 4 speed gearing original PK XL 6 pole ignition (flywheel 1.8 kg) So my first idea is to enlarge the base ports something like that, but maybe not that extreme. Plug in the Polini 24 membran/reed manifold. But as I was reading through this forum I found @závodní vespe v90 and that was really impressive So now I am think about this new Setup: Polishing the old style polini head Polishing exhaust port Enlarging base ports Pluging in reed valve manifold Cylinder timing 120°/175° + the same old stuff mentioned above My question... Do you think that this would be good touring setup with normal running speed around 85-90km/h? What else can I do to gain more power without changing any parts? Thank you for any helpful comments