Hitchcocks Forum

On my 2nd bike a 1956 16ms, regulator won't cut in without me helping it,when it does dynamo is charging ok.can the reg be adjustied ?
Cheers jenks

I believe you can take off the cover and clean the contact points inside. Or you can get an electronic regulator that fits inside the case to retain the original look.

I think the points can be adjusted also. You should be able to find info on that with a google search, I found a copy of the lucas service book fo their magnetos on line.

Yes they can be adjusted but don't just go in there and start fiddling with the adjustments read up on how they work and how to adjust it correctly.

Incorrect adjustment can lead to an under charged battery, an over charged/destroyed battery, acid leaking all over the bike, or the battery discharging itself through the dynamo field coil when the engine is stopped probably with a destroyed dynamo as the result, as netshubby says a modern electronic replacement is probably the best option, if the bike is positive earth then it will fit on very easily, negative earth is more difficult and the easy way is to buy a positive earth unit and reverse the polarity of the bike by reversing the battery and flashing the dynamo.

Far too many regulators die at the hands of uninformed attempts of fixing them...


Track down your nearest service agent (Lucas?) who KNOWS how to set and adjust.


How are the brushes and commutator?

Adjusting the cut-out of a Lucas regulator isn’t difficult as long as you’re prepared to accept the risk of having to replace the dynamo and/or regulator so if you do any of the below it’s at your own risk.


Be certain of what you are doing and what you must do if the cut-out remains closed and the engine stops. Do not attempt to adjust the voltage regulator as this is very difficult to get correct.


This diagram may help identify the parts.


Regulater/Cutout Box Layout & Settings


Having previously striped the bike for access to the regulator, removed the cover, correctly identified the cut-out points and slackened the adjuster lock nut.
1/ with the engine running at just over tick-over unscrew the cut out adjuster slowly until the cut-out points close.


2/ drop the revs to tick over observing the cut-out points.

2A/ if the cut-out points break then raise the revs again to check that they close, if they do tighten the lock nut, job done, if they stay open raise the revs a little more, if they close, job done if not go to step one and start again.


2B/ if the cut-out contact points are still closed raise the revs again and turn the cut-out adjuster in by a small amount, repeat step 2A.


IMPORTANT:

If at any time the engine stops, and you can start it again within a second or two, do so or you must cut the flow of electricity as soon as possible by one of the following open the cut-out points by hand (careful not to damage them), disconnect the battery or the dynamo. Failure to do this quick enough will burn all or part of the charging system out.


Please note that the bike will not be charging at tick-over if it’s set like this, so if you run the bike at tick-over with the lights on it will slowly run the battery flat.

Thanks for the information,seems the safest thing is to buy a modern regulator
Cheers
Jenks