Problem Vespa PK 50 S Automatica

  • Hello Vespa drivers,

    Let me introduce to You first. My name is Klemen and I am from Slovenia. I am sorry to write You in English because I have never learned German language. Browsing WEB pages I found Your forum. Unfortunately we do not have it in Slovenia.

    Maybe You can help me with your experience.

    I have big problem with my Vespa PK 50 S Automatica (VA51T motor: VA51M). I bought it last year and completely renovate it. First I had problems to drive in hill I lost all power and I have big difficulties to come on the top of it. I found out that variomat spring is not original (235657). This year I changed it with original and I changed also belt. Now I have opposite problem. Driving in hills is OK but end speed fall to 35 km/h. During driving I feel power of engine but variomat does not change “shift” to go faster.

    What should be wrong? Is it correct that this typ of machine does not have variomat rolls? Where should be spring placed: between both discs (Nbr.: 6 and 8 or like shows picture in link:

    Maybe previous owner did not assemble correct all parts. I assemble it like it was before.

    I count on Your help.

    Thanks in advance

  • Hi Klemen,

    I have the same Vespa model as you do, but it's a long time ago since I worked on it... However, according to the picture I'm quite sure that this is the right order of the parts. The belt is running between the two cone plates (no. 6 and 8 ), so the spring needs to be assembled below plate no. 6 to give the right pressure on the belt. Try to follow the picture if your assembly still looks different than this.