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[Starfield]

The Bullet has run well and is now my regular ride but recently it has become a little harder to start. This seems to have coincided with some night riding. I checked the battery today and it's down to 11.5v with no load and drops to about 9v when the ignition is on. It will just about start at that level and the meter then shows a charge rate of 12.54v. This seems low but then its only being fed by 4 coils. Agonising over whether i have a failing battery, a failing regulator or 'they all do that sir'.

Had a look at out hosts website and they only seem to offer a Boyer Powerbox as a replacement and I am reluctant to spend £67 + Vat & postage without being sure which part is faulty. It's not desperate as clearly once running there is enough juice to keep the sparks flying and the headlight is fed direct AC anyway. For now I will pop it on the charger overnight just to be sure of a good start in the morning.

Would welcome any thoughts on how to isolate the problem.

PeterF

[PeteF]

Do you have a charger/can borrow one?
Put it on charge overnight then check the voltage with a load on. If it still drops, the battery is duff.
Also worth checking your earth is sound. A dodgy earth can rob the volts.

[stinkwheel]

Honestly, sounds like a dead battery if you're seeing the output go up over 12v with the engine running. See what voltage your battery gets back up to on the charger then see if it'll hold the charge (leave it disconnected on the bench and check the resting voltage every few hours). A really healthy one will be getting up to 13v+ and staying there. I bet that gets up to just over 12 then drops down to 12 or even below over the next few hours.



You can do a dynamic test of the DC output by measuring AC voltage output between the two violet wires going into the rectifier (while disconnected) with the engine running. Watch you're not touching them, it can give you a dunt (mine will happily put out 30VAC which you will feel if you get in the way of it.)



You can fit a cheap second hand Japanese reg/rec to a bullet in place of the standard seperate regulator and rectifier units if the battery checks out and the charging system is producing an output. Mine has a ZX6R one on and has had for 6 years now. Cost me a fiver at an autojumble. I did an instructable on how at the time: http://www.instructables.com/id/Fit-a-J ... o-a-12v-A/

[Adrian]

Part of the reason for the higher cost of the Powerbox is the inclusion of a capacitor to allow for battery-less running, a generic single phase reg/rectifier from the mysterious East will be a fair bit cheaper new, if the second hand option doesn't appeal, e.g.



https://www.ebay.co.uk/itm/UNIVERSAL-RE ... Sw7p5aec1D



I tend to agree with the dead or dying battery assessment, though.



A.

[Barry_Q]

I had charging problems on my Lightning last year. It turned out that two magnets on the alternator rotor had made a bid for freedom, but got turned into grinding paste for their efforts.

[Beezabryan]

The battery is farked

[Starfield]

I wrote a lengthy response to the various replies to my question which seems to have disappeared into the ether so I'll try again in abbreviated form.

Battery charged to 13v overnight, dropped to about 12.5v later. Took it for an 80 mile run and battery was showing 13.1v when i got back dropping to round 12.5v later. Running the engine at that point showed a max charge rate of 12.9v which is odd as it must at some point on the run have been putting out well over 13v to get the battery up to 13.1 at the end of the run.

Nothing conclusive but at least it looks as though I can ride the bike safely for the moment. I don't think its the battery but I will fit another known good one asap to see if that gets the regulator working better. Mine is a combined reg/rec by the way not the separate rectifier reg units mentioned in one of the links provided.

Thanks

PeterF