Tomos A55 Technical and Tuning

Technical:

49cc two stroke
38mm X 43mm Bore/Stroke
10:1 compression ratio
Automatic 2 speed transmission
Piston port intake
Dellorto PHVA 14mm Carburetor (#55 main jet, #25 pilot, #40 choke)
Gearbox oil: Type A or Type Automatic Transmission Fluid
Spark plug: NGK BR8ES, Gap = .85mm
Front Sprocket: 26T
Rear Sprocket: 31T
Chain Size 415 x 104 links

Tuning:

Deristricting

The A55 engine was so well designed that restrictions were put into place to pass emissions and safety standards.

Replace the larger 27T rear sprocket with a 22T or 24T. The 22T will give you the best top speeds but you will lose low end. Not good for areas with big hills and heavier riders. 24T is the best all around size for higher top speed, but retains good low end power.
A55 Speed Kit- High flow air filter and jetting. Increase top end and midrange. Best used with a performance exhaust.
Performance exhaust. Stock exhausts are not designed for performance, are very heavy and restricts flow. The key to unlocking the power of a 2 stroke is in the expansion chamber.

HERE is a great write up from the Netherlands. Provides good knowledge of the A55 engine based mopeds along with general engine basics and tuning tips. Written by Marctraider

The title says it all.... Mostly for the advanced tuners.

UNDER CONSTRUCTION: More info will be added soon. Please check back!