Please can any one shed some light on this for me.

I fitted a new battery to my sf 4 3 weeks ago, because the old one kept going flat.
I used it 2 or 3 times the first week with no problem, before going on holiday for 2 weeks.

When I got home and started the bike, she fired up first time so I was a happy that it was the battery at fault.
I used it for the next too days with no problems 60 mile round trip back and fourth to work, untill today.

I left work, she started fine, rode the 15 miles to the petrol station were I filled it up.

Tried to start this time and the battery was as flat as a pancake, the motor would hardley turn i had to bump started her. When I got home (only about a mile from the garage) I tested the battery voltage it was only 11.48 volts.
I have check to see if its charging, and get 13-14.5 volts when with the engine running, depending on revs obviously.

Any ideas what might cause this really sudden drain on a battery that seamed fine only 20 mis earlier.

Cheers Colin

Sounds like sudden battery knackering caused by the regulator/rectifier failing. This can just happen at any time and can completely ruin the battery very quickly. However it can also be caused by bad contacts etc.. folllow the link below and download the fault finding guide, follow it through and you should find the fault pretty quick, it only takes about 15-20 mins to do.

http://www.electrosport.com/technical-r ... -guide.php" onclick="window.open(this.href);return false;

if the reg rec is faulty there could be two issues.one would be that it fails completely and no charge at the battery occurs,but you say you get 13-14.5 volts depending on revs.the other fault could be that it stops regulating the charge and ultimately burns out the battery,signs of this would be a very high charge rate which you dont have.


the charge rate should be 13.5-15volts at 5000rpm.there abouts anyway.check all connections.



wull

before i fitted a new reg/rec to my old sf it ahd intermittent fault.. so reg/rec showed as fine most of time when testing.. was weeks b4 i got a result showing me it rly was forked. new one solved it.

superfourben wrote:Sounds like sudden battery knackering caused by the regulator/rectifier failing. This can just happen at any time and can completely ruin the battery very quickly. However it can also be caused by bad contacts etc.. folllow the link below and download the fault finding guide, follow it through and you should find the fault pretty quick, it only takes about 15-20 mins to do.

http://www.electrosport.com/technical-r ... -guide.php" onclick="window.open(this.href);return false;

Thanks for that, I followed the chart and it appears that my charging system is working perfectly "at the moment".
I think it is like meno had, the R/R has a intermittent fault.
I am going to persevere as a new one is about £70, and I am not to flush at the moment.
Thanks for you help, I will keep you all posted.

you can test the reg/rec itself which may show it to be faulty.the test is usually not required as the usual test is enough to determine if its faulty or not.the fault finding diagram you followed if i remember correctly doesn't show how to test the reg rec....it might do but i cant remember.



wull

There's a reg/rec test procedure in the Russian workshop manual that's pretty straightforward to follow.

HTH.

alexibrow wrote:There's a reg/rec test procedure in the Russian workshop manual that's pretty straightforward to follow.

HTH.

I did look at that, but I am not the best when it comes to electrics, it might as well have been in Russian.

Can any one explain it in english for me ?

Cheers Colin

Section C (or page 3) of the test shows how to test the reg/rec. I had a problem with my bike and only by testing the reg/rec did I find it was at fault.

If you need a reg/rec you could buy mine if it fits... its for an nc23?