dynamo servicing tech guide ?

[asterysk_usa]

Is there a tech article for servicing/refurb of the dynamo , I'm assuming it will mean replacement of springs and bushes and possibly bearing replacement but would be good to read about someone who has done it before. As an aside, the cost of a refurbished one seems high, which makes me think there might be something else that often goes wrong

[ajscomboman]

You can buy a service kit from e-bay which will have everything you need to overhaul a dynamo. Excludes brush holders and end cover naturally.

[G15 Roy]

You can buy a service kit from e-bay which will have everything you need to overhaul a dynamo. Excludes brush holders and end cover naturally.

or of course he will do it for you

[ajscomboman]

You can buy a service kit from e-bay which will have everything you need to overhaul a dynamo. Excludes brush holders and end cover naturally.

or of course he will do it for you

Steady on now, you're the one who always told me to give up building work. After messing about with them for 30 odd yrs I'm only taking your advice!

[Mick D]

Hi

Check out the Bright spark magnetos website - http://brightsparkmagnetos.com/library/ ... /index.htm

Plenty of good info from original Lucas documents.

Regards Mick

[asterysk_usa]

Hi

Check out the Bright spark magnetos website - http://brightsparkmagnetos.com/library/ ... /index.htm

Plenty of good info from original Lucas documents.

Regards Mick

Thankyou , that's an excellent source of information. I had my magneto refurbished at Bright Spark a few years back but had forgotten about the library.


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[SPRIDDLER]

There's also another electrical and mechanical guide to our bikes which may be useful for future needs:........

https://matchlessclueless.com/

[Group Leader]

Well I've done mine twice now in 2 and a bit years and got some "lessons learned" (the hard way!). There are many other threads with various trials and tribulations, heres mine:

http://www.jampot.com/forum/viewtopic.p ... lit=dynamo

Some very good advice from people like Groily and Co.

Things I've learnt include:

That current (no pun intended ... ) spares are not always precisely correct and may well need some engineering (rather than general) fettling like skimming the diameter of the bearing surface on the armature to get a good fit rather than relying on "persuassion".

Be very careful if you remove/change the field coil - the special tools listed in the contemporary service manuals are there for good reason; the arm screw driver enables you to pinch up the pole piece very, very tight (essential). The shoe expander stops you deforming the case when you are using the lever screw driver ....

A simple test is to isolate the dynamo, connect the F and D terminals together and to a suitable bulb with the other side of the bulb earthed. A fast idle / medium speed should light the bulb but don't over rev it.

You need to get the polarity of the field coil wrt the armature correct otherwise nothing happens.

Motoring the dynamo (connect D & F to the "live" side of the battery with the dynamo earthed to the otherside of the battery) demonstrates the basic soundness of the dynamo. The dynamo should rotate in the same direction as it is driven by the engine (anticlock looking at the drive sprocket)

.... and so much more!

HTH

Alan

[cfaber]

One thing you can do to "wake it up", rather than putting current through the coil (which could cause it to burn out if you're not extremely careful) is to just use a strong magnet on the outside of the case right up against the flat head screw which holds the coil in place. I did this to wake up mine almost instantly.