Triumph - Pre-Unit - Electrics & Ignition


  • Magneto rebuilds
  • Electronic Ignition conversion kits K2F & K2FC twins
  • Electronic conversion kits M01 singles
  • Dynamo rebuilds
  • Electronic DC regulators 6V / 12V
  • LED & Low wattage bulbs
  • Alternators & Rotors
  • AC regulators single / three-phase
  • Timing kits
  • Special ignition prototypes
  • Electrical fault finding





We specialise in the renovation of the LUCAS K2F and K2FC magneto as fitted to BSA, TRIUMPH and NORTON twins.


The most common problem with original magnetos is failure once hot. The engine will start from cold, then run for a short while, a misfire will develop, and the engine will finally stop. 

Once the engine is cold again, the engine will start. This is usually due to a breakdown in the insulation of the condenser or the armature windings themselves.

When we undertake a renovation of these magnetos, we examine the following:-

  • Mechanical - Bearings, insulation, washers and shimming of the armature
  • Electrical - Armature windings, Condenser, Slip ring, Points and Bushes
  • Magnetic - Check magnetism and Remagnetise magneto body
  • Ignition - Check Spark strength, Spark timing and stability

We use the CRYPTON MAGMASTER (from the 1950s) to do a comprehensive testing programme on each magneto we rebuild. This allows us to make slight adjustments to the magneto to achieve the best constant and accurately timed spark that the magneto can produce.

The final 20-minute hot running test programme includes:-

  • Checking the standard spark HT Voltage;
  • Checking the maximum available spark HT Voltage;
  • Checking the ignition timing stability over-rev range;
  • Checking the ignition timing for the correct timing angle (for most twins, this is 180 degrees);

By performing this test programme, we can be confident that the magneto you fit your engine will be at peak performance and will remain reliable for years to come

Send your magneto to us. We will test it to ascertain its’ faults, provide an estimate and contact you to discuss the work required.

Our two-year guarantee backs each Renovated magneto.

Have you considered replacing the magneto with electronic ignition?





At SRM, we specialise in renovating these particular models of LUCAS dynamos.

In the 1940s, the LUCAS E3H (40 Watt) unit was used extensively on various British single-cylinder engines, later replaced by the more powerful LUCAS E3L (60 Watt).

The E3L dynamo was used on many British twins such as the BSA A10, TRIUMPH T100, T110 and NORTON DOMINATOR.

The design of this dynamo is the same throughout the range, but different driveshafts are used for other models.

Each dynamo is tested on the CRYPTON ELECTRICAL TEST BENCH to determine its condition, and an estimate of the cost to renovate the unit is produced.

If the dynamo were fully restored, a new armature and field coil would be fitted with new bearings. The outer body would be Nickel plated, and the alloy ends bead blasted. New brushes would be fitted, and the dynamo would be thoroughly tested.

Firstly the dynamo is wired for a ‘motor’ test - this runs the dynamo as a motor, and the motoring speed is checked, as is the polarity and rotation. This test also polarises the magnetic field in the field coil core;

The dynamo is then fitted to the CRYPTON ELECTRICAL TEST BENCH to be driven as if the dynamo were fitted to the engine. This test confirms that the dynamo will charge when fitted to the engine and in the correct polarity for the earthing system on the bike.

A two-year guarantee backs each Renovated dynamo.