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Charging troubles

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the-chauffeur:

Not the first time this topic has come up, I'm sure, but I'm getting a little fed up with the lack of charging power on the K2. To be fair, I've always known the charging circuit wasn't up to much, but I'd not realised just how bad it was until I rode home from work tonight.  It's a 17 mile journey and for most of it, I had barely a candle glow from the headlight - and for a large part of the journey the battery didn't have enough power to run the headlight and run at anything over 50mph.  Not a pleasant trip.

Some background - my K2 has a modern reg/rect in place of the original parts, which would now be 40 years old.  I've also swapped the tail-light/brake light bulb for a LED replacement.  The trouble is the draw from the headlight - I switched the ludicrously low powered sealed beam unit for a halogen replacement, but it seems that unless I keep the bike at high revs the whole time the light is on, it drains the battery in minutes.  Everything's grounded properly and I've installed relays to take the switching load off the handlebar switches. 

So other than change back to a sealed beam unit, what - if anything - are my options?  And should I really be suffering this badly with the draw from the headlight?   I had no idea the halogen bulbs were quite so power hungry . . .

Thanks all.

Bryanj:
If the generator is in good nick it should cope with a Standard H4 halogen bulb at over 3,500-4,000 rpm.

Have you got a multimeter either analogue or dige and i will give you some tests not in the book mate

SteveD CB500K0:
You need to do some basic faultfinding.

Check the battery voltage at the terminals:

* Ignition off
* Ignition on engine off
* Tickover
* 3000 revs
Post results

steff750:
 :o its the stator it cant make more power than it was designed for.like bryan said they will cope with h4 h/light bulb
 you are taking to much power out of the battery  before long you will be pushing the bike home, modern regulator and rectifier dont change anything you need to go back to standard lights, make sure all your bulbs are correct ratings (check in handbook or manuel) as these bikes are forty years old and not able to cope with modern electrics ;)

UK Pete:
My F2 is f---king awful at night , i will not ride this bike in the dark anymore , you just cant see a thing, i went out for a ride with mates at night and got left behind cause i felt it was really dangerous to be going the speed they were on there newer bikes, at one point i thought the bulb had gone and it was  just on side lights, but when i checked it was on just useless,
If there is a cure i will alter mine as well
Pete

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