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By Adrian
#49351
Unless you bought a very low amp-hour battery the charge should not drain away before your eyes. First check with the battery OFF the bike, charge it fully, leave for a couple of days then come back and try the headlight bulb across the terminals, if it lights up brightly the battery is fine, if not it's a dud battery.



Assuming the battery is OK, then you have problems elsewhere in the electrics. I don't know if your system is 6 volt or 12 volt, DC lighting only or the later version with AC headlights, but try isolating the regulator/rectifier from the frame or earth and see if the charge still holds up with the parking light on. If it does, then these components need replacing. Also check the wiring to the light switch in case there's anything wrong there. A wiring short circuit should just blow the fuse to the battery, but you never know. I once managed to wire both dipped and main headlight beams to come on at the same time on a bike, which drained the battery very quickly!



A.
By bmh67
#49496
Thank you Adrian, for your advice.
I isolated the rectifier from the frame, it seems that the battery keep the charge then.
I have also noticed that the rearlight/breaklight are very sharp and clear, a second or two, the it dims down.
Have ordred a new rectifer, so I will replace it when it arrives.




Regards from Norway
By bmh67
#49940
A little update on my Enfield......it`s easy to start now, runs very smooth for 8-10 seconds, then it stops, and when I turn on the ignition again, the battery is almost out of power,
even if it`s fully charged when I start the bike.

So, I guess I have to get me a new battery, now I got a 12 v 5 ah battery on the bike, anybody knows if thats the right size? Or should it be bigger, more amper?





Regards from Norway.
User avatar
By Adrian
#49949
5 amp hours sounds about right for a kick start bike, which your '68 ought to be! Hopefully it's only a dud battery, but if not I'd be very tempted to rip all the electrics out and rewire/replace everything starting with a new 12V alternator, genuine Lucas RM21 or its Sparx equivalent, and good soldered terminals throughout, adding separate earth wires where needed.



Assuming no indicators for a '68 bike, use heavy duty 7 core trailer flex as the basis of your wiring loom, though even if it does now have indicators 7 core flex will be enough. The wiring diagram for an old Brit single running a 12V single phase alternator is about as simple as it gets. Otherwise I have posted elsewhere about the new 12 core flex which allows a few extra options. Ideally I would also fit a reconditioned SR1 magneto and auto advance/retard unit and junk the coil ignition, making the wiring even simpler.

A.

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