Dynamo Repairs and Services

Dynamos can often be recommissioned simply by stripping, cleaning, and rebuilding. If this is the case only the standard charge applies, plus the cost of any additional parts deemed necessary during the rebuild, but it may be possible to avoid the expense of a new armature or field coil.

You may want to undertake your own dynamo test so, before sending it to me, here's a stage by stage dynamo testing support document. Link to dynamo test page. It takes a while to download - be patient!

If you've tested your dynamo and you can't get it to charge here are some things to try.........

  1. Spin it faster! Your dynamo should achieve sufficient output at about 1400 r.p.m. maybe more or less depending on various factors.

  2. Clean the commutator with very fine emery, about 1000 grade.

  3. Check the brushes aren't stuck in their holders.

  4. Check for dirty or poor connections.

  5. 'Flash' the field coil. Instructions are in the dynamo test document.

  6. Swap the field coil leads.

The prices below apply to most post-war, Lucas two brush types, e.g. E3L and E3H . When sending your dynamo please make sure I know which way it rotates; the arrow on the casing is not always correct as dynamos have often been moved from one bike to another and the internal wiring altered. I also need to know whether your bike is wired +ve or -ve earth and whether you are running a 6v or 12v system. Scroll down for prices:-

Price guide valid until 1st June 2022

Remember! No need to add VAT, what you see is what you pay!

Standard charge to strip and rebuild all dynamos £65.00

Basic refurbishment (brushes, bearings, UK made armature) £120.00 + standard charge

Full refurbishment (brushes, bearings, UK made armature, UK made field coil) £160.00 + standard charge

Additional parts fitted at normal retail prices - see Link to Dynamo & Regulator Spares page.

Individual jobs, i.e. not part of a general refurbishment. There may be a discount where jobs are combined.

Repair brush carrier plate (your brush carriers transferred onto new backing plate) £20.00

Paint body £12.50

Exchange body for newly zinc plated body £25.00

Fit new bearings £17.50

Fit new field coil £45.00

Any other parts required will be supplied and fitted at the normal retail price. Please see my Link to Dynamo & Regulator Spares page

Refurbished dynamos should not be used for 12v unless converted to 12v.

12 volt conversion

Your E3L / LM / LO dynamo fitted with 12v armature and field coil. New brushes and bearings included. £175.00 + standard charge

12volt regulator £ 24.95

12v. battery, horn and bulbs can be supplied at competitive prices.


Dynamos will be wired according to original Lucas specifications. If you use a regulator which requires

non-standard dynamo wiring you will need to refer to your regulator fitting instructions.


Please check my Terms and Conditions page for postage prices and guarantees