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.........
Spin it faster! Your dynamo should achieve sufficient output at about 1400 r.p.m. maybe more or less depending on various factors.
Clean the commutator with very fine emery, about 1000 grade.
Check the brushes aren't stuck in their holders.
Check for dirty or poor connections.
'Flash' the field coil. Instructions are in the dynamo test document.
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:-