Vespa 50ccm tuning

Hi! I have a 1970 model Vespa Piaggio 50ccm.
Chassis Number V5SA1T41411 that I will tune.
What kind of cylinder, carburetor, exhaust should I choose to get it to work fine. Thought of 75ccm/85ccm cylinder. Wish me good power at low rpm. Maybe upgrade to electronic ignition later. I guess I should change the oil seals and sealing rings. Should I mount the reed valve?

Regards bjella

If you read through all the messages in this forum there are plenty of requests and replies for this kind of information.

Why limit yourself to 75cc?

The biggest you can go without changing your crank is 112cc either polini or molossi.

These kits require a minimum of a 19mm carb.

Exhaust. Polini snail would be the minimum you want to consider.

If you are considering changing your crank you can go up to 135 cc and use read valve. The sky is the limit and so is the budget.



I guess it depends of what you deserve.


If you want to spend less money and get a good power increasement my recommendation would be a 75DR cylinder by using the original carb. with a bigger mainjet and a sito plus or a banana pipe.

Fix the ignition timing to 17 degrees and use a W4AC spark plug.

In this case you can stay with the original gear ratio.

The result should be a good torque and 60-70 km/h maximum speed.



If you want to have more my recommendation would be a Polini 102ccm in combination with a race crank a 19mm carb and a polini snail pipe.

In this case you have to use a longer primary gear (3.00) and you have to fix the ignition timing to 17 degrees and use a W4AC spark plug.


The result should be a higher tourque in all refs and you´ll get around 90 km/h.