• 5 port hard chromed sleeve
  • CNC machined flat piston
  • Aerodynamic "knife edged" connecting rod
  • Turbo combustion chamber with cooling fin
  • 15mm high quality main bearing
  • Composite slide valve carburetor
  • 8mm aluminium venturi
Technical data:
  • Displacement: 3,49ccm
  • Max power: 2,50 HP @ 40.000 U/min
  • Bore: 16,26mm
  • Stroke: 16,80mm
  • Front bearing: 7x19x6mm
  • Rear bearing: 14x25,4x6mm
  • Glowplug: Sonic S7C turbo
  • Weight: 325g
The all new Sonic ProStock.21 3,5ccm on-road engine is designed especially for club and regional racers that are looking for a competition engine for a good price. Additionally the ProStock.21 is easy to adjust and to handle which helps the racer to focus on driving and setting up the car.

Equipped with a 5 ports sleeve and a CNC machined flat piston the engine provides great power over the entire RPM range while having a very efficient fuel consumption.

The optimized crankcase and the the "knife edged" aerodynamic connecting rod help even more to reduce turbulences inside the engine.

A special turbo combustion chamber with a cooling fin and the lightweight cooling head ensure best heat dispersion to keep the engine temperatur at a moderate level.

High quality ball bearings and a modern composite valve carburetor with an 8mm aluminium venturi complete this new high competition engine.
motor5 thumb1
motor5 thumb2
motor5 thumb3