Powerdynamo, different rotor weights

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Technical Help



different rotor (weight) available - which shall i use?


For many (not all however!) we offer rotor in 5 different weights (plus for racing systems a rotor 230gramms)
choice is limited by physically available space, both in diameter and height. Some rotor demand in some systems a different ignition coil
  • rotor 0.7kg (ca 25oz), outer diameter 103mm
  • rotor 1kg (ca 38oz), outer diameter 112mm
  • rotor 1.4kg (ca 51oz), outer diameter 112mm
  • rotor 2kg (ca 70oz), outer diameter 128mm
  • rotor 3kg (ca 102oz), outer diameter 137mm

we often get asked:

which one shall i take?
  • first of all, look carefully for the space available. you can not place a 128mm rotor into a space confined to, say 105mm.
  • also it is nonsense to use a 3kg rotor on a small 50cc
  • use the one which is nearest to stock rotor weight (note however that in very old engines, notably those from before WW2 rotor weight has sometimes been extreme as one could not get enough electricity out otherwise, here replacements are significantly lighter)
generally good are flywheel/stator weights
  • STREET: 0.71KG, 1KG or 2KG
  • MOTOCROSS: .7KG or 1KG
  • FLATTRACK(short track): 1KG or 2KG
  • FLATTRACK ( mile track): .7KG or 1KG
  • ROAD RACING: .7KG or 1KG or racing system 230gr

  •   (Note however that as we do not permit use in competition, warranty may be voided)
Adding weight:
  • Smoother idle 
  • Better traction
  • Smooths power delivery(engine revs slower)
  • Reduces stalling at low speed
  • Requires more braking to slow down.
Reducing weight:
  • Rougher idle
  • Less traction
  • Increases acceleration(engine revs quicker)
  • Quicker throttle response
  • Easier to stall at low speed
  • Less braking to slow down
Please do not experiment too much! Better stick to the stock weights as far as possible. Whatever you think is good for your engine need not be what the engine takes as good!

Electrically the rotor 103mm (mostly) differ to those with larger diameter in the strength of the magnets and as a result the ignition coil used.

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