I have a 929RR with a fairly long-standing battery issue. I'll post a "Too long, didn't read" at the bottom, but here's the full story for anyone interested.

I've looked here and elsewhere for threads with a solution but I'm still lost. Most all of the suggestions to similar sounding issues seem to be ones I've already addressed in some way or another.

I believe the bike had a new battery when I bought it, and that lasted about 2 years without issue before it went flat the first time. I would charge it up from time to time with a fairly cheap motorcycle battery charger I bought at the time. When it kept going flat I took it to my usual mechanic (who is great value, but no electrician) who said he 're-wound' the stator so it should definitely be charging. Kept happening so I figured it must be the battery. I bought a cheap battery (I think intended for smaller bikes, but physically the same size). This worked fine for a few months, then the issue returned. Kept going flat until it became basically unusable.

My housemate had a good quality new battery lying around for maybe 6 months, intended for his dead R1. I gave that a charge with my new, expensive battery tender, and made use of that, but again even though it was ridden at least every couple of days, it still started going flat after a couple of months. It again came to the point where I could connect the battery tender every night, and start it in the morning but I'd be bump starting it to get home after work. Once out of the blue it went dead half way home from work, so the lights and other electrics were dead, bike was running horribly and wanting to stall, and was probably in danger of overheating. Ended up having to push it the last couple of streets home.

So I again sought help. Trusting my mechanic who says mechanically it is fine, I found an auto-electrician who would look at it (the only motorcyle specialist auto-sparkies are really far out of my way, and most of them weren't interested). He kept the bike for a few days and insisted that the battery was relatively ok, the bike was charging fine at idle, there were no shorts he could find and the battery wasn't draining at all when left alone for a few days. He said either the problem was only happening while the bike was driving, or perhaps the battery was just not quite up to it. Sure enough after a few days riding the problem was back and again eventually got the point even daily connection to the battery tender couldn't keep it running.

So I just recently bought a brand new (Yuasa brand, I think?) battery. The most expensive they had to suit my bike. It has been fine for a couple of months, although as a precaution I've been still using the battery tender whenever I'm riding my 250 instead (I tend to alternate between 2 bikes and car). Today is the second day since I swapped the bikes and took the 900 off the tender, rode to work, home, to my language class and then the bastard thing wouldn't start after...

I also have another ongoing issue no mechanic wants to fix, with indicators taking forever to come on when it is cold outside. I can live with that if need be, as annoying as it is. I mention it only in case it is symptomatic of a related problem.

TL;DNR?

Pretty sure bike is mechanically fine.
Two electricians insist the stator is charging at idle and battery isn't noticeably draining over time.
Battery is good quality and brand new.
Have a good quality battery tender/maintainer which I'm pretty sure is also not the issue (it's never caused my 250 any dramas, and my other housemate uses the exact same one on his gsx-r 1000 for months at a time, and it still starts every time) - but not even this tender is enough to keep the bike going.
Every time I've replaced the battery it goes flat progressively faster until it is basically useless.


I really don't mind paying someone to fix this crap for me, but I've so far paid 2 bike mechanics and one auto-electrician to diagnose with no success. If this keeps up I'm nearing the threshold where I charge it up and sell it to some other poor bastard who hopefully doesn't come kill me in my sleep when it dies on him...

 

If the stator has been changed then most likely the rectifier is bad and is overcharging the battery which will cause the battery to die. This problem is very easy to check with a multimeter.

1. Check the volts on the battery with the bike off. It should be between 12.3-13.2 volts. This will show if battery is good.
2. Start the bike and check the volts at the battery with the bike @ 5k rpms. It should be around 14.6 volts.

If the volts are above 15.5 volts then the rectifier is bad and overcharging the battery.

 

The only way to check electrical is be methodical. It sounds like a charging issue.

Here are a couple of links that will give you a good background and a diagnostic
flow-chart. Read these and then drop back in...

Charging System Diagnostics - Rectifier/Regulator Upgrade - Triumph Forum: Triumph Rat Motorcycle Forums

https://cbrforum.com/forum/f2-tech-9...-solved-27739/

Technical Resources - Resources for Electrical Systems on Motorcycles and ATVs - ElectroSport

Hope this helps, Ern

 

Replace the stator with a new one and the regulator with a new one. Problem solved. You will go back and forth between the two till you are frustrated and pulling your hair out. Do them together and your system will be good for years. The 929 regulators are really good, so stick with OE. They are way better than the earlier model's r/rs.

 

I agree, most likely the regulator/rectifier.

 

I'm seeing R/Rs listed on ebay for anything from 100-150 AUD. My local Honda supplier want 172.50 for one.

Stick with the genuine Honda spare part to be safe you reckon?

 

I would go NEW with electrical parts. Ronayers.com is th best place for oem parts.

 

Ronayers.com will post me one for $120 or so including shipping.

Their online catalog suggests it has an OEM style plug but doesn't say a lot else about it (other than it supposedly doesn't get hot)

REG/RECIFIER HONDA - Shop Accessories by Make>Honda>2001>Cbr929rr>Electrical : 10-112X

Would you still recommend it? I've seen comments that people have had bad luck with non-Honda parts and that it's safer to go with those? I suppose the quality of third party parts is bound to vary, but can I trust these guys to stock decent ones?

 

Sorry to bump, but really hoping for any advice on this one. I'm thinking of ordering a replacement R/R either way, because the one that's on there looks quite old, and I've already got all the plastics and seats off anyway, plus I don't really have any other leads as to the cause of my problem so it couldn't hurt having a new one.

I just don't know whether to go with the aftermarket part as suggested above, or stick with the Honda supplier. They tend to be overpriced and it could easily be an aftermarket part anyway, I forgot to ask for confirmation but they'll usually say so if it's a non-Honda part.

I don't mind paying the extra $50 to my local dealer if there's a chance it'll make a difference. I want the best quality part that will be least likely to ever cause this frustrating problem again...

 

Any of the 3 options I know of, should be fine.

Either the OEM, the Rick's or the Electrosport.

Just be sure of the stator, it can cause further issues if it's
not up to snuff. +1 to Demon's comment on doing the r/r
and stator together.

The r/r is pretty standard technology, as long as you don't buy
'cheap', you'll be fine.

Hope this helps, Ern