Testing the charging system

[breakaway]

Hello KBers,

My 1989 CBR400RR is now my only bike, so I need it running 100%.

Recently, It's developed a problem:

I used to ride everywhere with the headlights on, and never had a problem with it. But suddenly one day, I went to start it up as normal, and the starter went crank-craaank-craaaaaank and just died. I push started it, started and ran fine. That was the day of the ride to Kawakawa bay, so I rode it all the way there with the headlights off and after that it was fine.

Once I started riding around with the headlights on again, the symptoms re-appeared. The starter was noticeably weaker and it just wouldn't 'catch' as easily, sometimes I had to keep cranking till it ran out of juice and wouldn't crank anymore. (I presume this is because all the juice was going into the starter and none for spark).

If I ride around with headlights off whenever I can (i.e. before sunset), the bike is sweet. But once I ride with headlights on, it just doesn't charge the battery (too well).

I recently went on a little ride to Whangarei, and On my way back from, it was dark and I was riding with my high beams on. I stopped at a petrol station to clean all the bug guts off my bike, and when I got on it and hit the starter, it was VERY weak and just gave up after a bit. Push started it and it ran fine.

Bike idles fine etc, and is alright unless I ride w/ headlights.

What's the prognosis? Alternator on the way out? Shagged battery holding only a surface charge? I hope it's the latter D:

Here's something to consider: When I fell off it, I damaged the switch block, so the high beam was re-wired with a toggle switch - would this mean that when I flicked it on it wouldn't disengage the low beam like it normally would?

Is there some testing I can do at home to see what's up? I know my way around a multimeter.

TIA :apint:

[yod]

put your multimeter across the battery when its running - you should be getting around 14V

if it's not, then the alternator/generator is not charging

essentially you should see a decent increase in V when you start it up (from about 12 to 14)

[breakaway]

Idle Running: 13.8v
With headlights: 12.5v
Headlight + brake lights: 12.2v
6000 RPM with all lights off (cept neutral indicator of course): 14.3v


Is that about right?

[tri boy]

The first check to do when experiencing elec faults, is check the batteries "specific gravity" use a battery hydrometer.
A local bike shop will do this generally for free if you take the battery to them.
(better to have your own small hydrometer though)
Many, many charge problems are misdiagnosed because this test isn't performed.
The "surface charge" can be removed by turning the headlight on for about 10sec prior to doing the SG test.
I'm picking the battery has a dodgy cell, as the bike is still running after a week or so of riding with the fault.
Get it sorted before the Reg/Rec fails due to overheating/excessive charge/discharge cycling. MHO

[breakaway]

Alright so who has a hydrometer :third:

Might have to take it into Mt Eden MC, might be a bit of a problem seeing this is my only ride :o

[yod]

Idle Running: 13.8v
With headlights: 12.5v
Headlight + brake lights: 12.2v
6000 RPM with all lights off (cept neutral indicator of course): 14.3v


Is that about right?

yeah sounds fairly reasonable but tri-boy would know a lot more about it than I do

is it a sealed battery or not?

if not - the hydrometer would be a wise test

[tri boy]

Ooops:o forgot about those horrible sealed batteries.
A load meter test is the best way to test those. (very few bike shops have one)
Ride your bike to the shop. Remove battery, (after doing the surface charge trick), and then let them dip it if it's a non sealed battery.:cool:

[arj127]

i would just throw a new battery at it anyway for piece of mind and diagnosis elimination. Batteries will normally drop one cell and this is when they start mucking you around, starting/ not starting etc.
Put a multimetre across the battiery terminals and rev the bike to say 3000rpm and you should see the voltage increase to maybe 14v, then you will know wether or not you have a charging problem.
Best of luck

[breakaway]

What's a good brand of battery to buy?

[arj127]

supercharge do motorcycle batteries. you will need to measure yours and suss out how many amp hour it is. I'd recommend them. But, shop around anyways

[HungusMaximist]

Just make sure when you do get a new battery, make sure the battery is ACTUALLY DRY like there isn't any acid inside.

FRESH ACID packs should be supplied or they fill it up when you buy it. Don't ever buy a battery with the ACID alreadly inside, god knows how long it's been sitting and most cases, it's alreadly dead.

You shouldn't need to pay over $100 for a battery, replacement ones are really good these day as long you keep it charged once a month (when the bike isn't in use).

Ring up Mt Eden, Red Baron, Auckland Power Motorsports on Khyber Pass. Somewhere around the $50-$70 dollar mark.

[Ragingrob]

Sounds exactly like the problems I have that is finally fixed with a new regulator. Started out exactly like this, but reg would check out fine like you have found, then finally it gave up. Pretty much what was happening was that the reg was screwing up after it got hot or something, then would be fine and charge it back up and therefore test out fine. A common problem with honda's, so yeah. $180 or so from Red Baron for a new one.

[tri boy]

Thanks for posting your comment Ragingrob:yes:
This is why testing, (not just replacing for the hell of it) is done.
If the battery is indeed fine, (only guaranteed by a SG test), then throwing $100 for a new one only to later find it was the reg/rec, has just doubled the cost of the job.:pinch:
Not so serious on people with money to throw around, or on small machines like m/cycles, (forklift batteries can cost up to $10000), but for anyone on a budget, the cost of an unnecessary battery could have gone into a tyre, or chain, or 5 cartons of Tui:apint:
"Test and then spend" is a good rule of thumb.:sunny:

[Ragingrob]

Thanks for posting your comment Ragingrob:yes:
This is why testing, (not just replacing for the hell of it) is done.
If the battery is indeed fine, (only guaranteed by a SG test), then throwing $100 for a new one only to later find it was the reg/rec, has just doubled the cost of the job.:pinch:
Not so serious on people with money to throw around, or on small machines like m/cycles, (forklift batteries can cost up to $10000), but for anyone on a budget, the cost of an unnecessary battery could have gone into a tyre, or chain, or 5 cartons of Tui:apint:
"Test and then spend" is a good rule of thumb.:sunny:

Yep, I tested the reg time and again to no prevail, battery was fine but not EXCELLENT cond so I got a new one anyway just for peice of mind. Reg slowly got worse (and I mean slowly, took about 4 months!), would start cutting out with full headlights on, then low headlights and indicator at same time, then low headlights, until it blew and bike was running purely of the battery. Had a new reg for 2 weeks now and even the neutral light etc is so much brighter, had no problems at all and battery fully charged all the time.

So now I have a spare battery, which can't be a bad thing! :clap:

Was so hard to work out what was wrong, and to spend the bucks for a new reg unless I was sure. But you can't diagnose intermittent electrical problems easily if at all! So I was glad it fully blew so I was sure. Was a big rush the next day though as I needed my bike that night, sourced a new reg finally, discovered the original had melted the plug to itself, so had to rewire it and installed new reg and that was that!

[pete376403]

I post this so often it should be a sticky - the GSresources web site has a series called the Stator Papers http://thegsresources.com/garage/gs_statorfacts.htm
which has a shitload of info about how charging systems work, or don't work, and what to do to find the fault. Although this is a Suzuki site most of the information is pretty generic.