Regulator or diode?
 

I have a CBR600 F1 (2001) and been having problems for a while with a dieing battery. I thought it was just getting old and tired as it is the original battery (9 years old) and has been stood for about 2 months.

I bought a brand new battery 1 week ago and it died again yesterday. I have followed the Haynes manual for reg/rec problems and all loom readings come out as expected. Battery was 13.4V (charged) with engine off, 12.9V with engine on and does not increase when revved. I found a page on the internet that states these symptoms, rather than overcharging, is due to diode burnout. I have checked the diode and it seems fine so now I am confused as different information says different things.

Does anyone have ideas if this is the reg/rec?

sounds like your r/r has failed. it's pretty common. does the charging voltage get to 13.4 at 4,000 or so rpms? i bet it doesn't.

No, revved up to 5500rpm and will not go above ~13V. Can the problem of not increasing voltage be purely the r/r being knackered? Everywhere I have seen is it overcharging.

most likely, yes. you will want to check the stator to make sure its not shorted to ground and that the winding is not broken. you would hate to fry a new r/r. you may find the plug for the r/r pretty cooked as well.

under 13v at rpm in not charging. it needs to be 13.4v to 14.5v.

I have tested all the wiring to the stator and seems fine as stated in the manual. I haven't opened it up so not sure about the interal components, if they are causing a problem at all. All the plugs off the r/r seem fine as well with nothing out of the ordinary.

I am definately not getting that voltage and apart from it not charging, everything seems normal.

you don't need to take out the stator to check it. if the ohm tests all are good, then its probably okay. replace that r/r, and you problems should be solved...

demon

I'm gonna say, I think demon's giving you the straight skinny. What you've got going
on, is the early stages of r/r failure. If the system is healthy, you should easily get
14+ volts at 5 grand. You aren't over-charging, until you hit above 14.8/9-ish volts.

You sound like you know how to read a meter, so I'm going to assume your stator test
is verification that it's fine. So that only leaves the r/r as a culprit. If it's the original
OEM, with a smooth epoxy fill and NO fins, I'd replace it as a standard preventitive
maintenance. Whether it needed it or not. This is one of the only, known faults,
in the entire line of Honda's for this era. The other being a unusually, high failure-rate
of the automatic Cam Chain Adjuster (CCT).

Hope this helps, Ern

Thanks for the replies. It is the original r/r yes but it DOES have fins. I am highly considering replacing anyway if the majority vote is for the r/r as I am going on a long ride next week and don't really want a flat battery half way there! I just wanted to get an opinion on the diode but that seems to be OK so I think I can rule that out.

The heat from the r/r within literally 1 or 2 minutes is very hot and I am no temperature gauge myself but it felt as hot as my engine after a long ride when the bike was warmed up properly.

Oh, I have had the CCT before and due again soon I think!

what does r/r stand for?

Regulator/rectifier