Bike conked out: Battery, Regulator or Alternator?
Bike conked out: Battery, Regulator or Alternator?
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TorqueDirty

Original Poster:

1,647 posts

236 months

Monday 25th August
quotequote all
OK, so my 1999 Fireblade completely conked out yesterday. I was out for a ride and it started to feel a bit odd - kind of lumpy.

I changed the rear wheel bearings last week and was worried that I had ballsed it up and that is why the bike felt strange.

Decided to pull in to a retail park to check the rear wheel but as I was going slowly round a roundabout the bike just died. Had to push it off the roundabout and up a hill to get it out of the way.

I switched off the headlight and managed to get it bumped started then rode it home trying to keep the revs up and not use the brakes too much (in case the brake lights coming on would make it cut out again).

So, I made it home but now I need to fix it. I gather the regulator / rectifiers are a weak point on these bikes so I guess that is a good place to start, and there is every chance that the battery is old.

I did put the battery on charge yesterday and the Optimate charger says it is fully charged now, but I had it on charge for a few days the other week so something must be wrong.

I'm hoping it is not the alternator.

Any suggestions as to the best way to navigate though this? Break out the multimeter or just buy a new battery and regulator / rectifier and hope for the best? It is a 26 yr old bike so it would be no bad thing to replace the regulator anyway.


ssray

1,222 posts

242 months

Monday 25th August
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In order of normality (made that up) for Honda's
Reg/rec replaced with a Yamaha R1/r6 unit, the live and neutral needs swapping over in the plug, if you muck it up it's only the 30 amp fuse that blows -cosr from about £15 used on evilbay

Connection in-between the altanator and the reg/rec - goes high resistance with corrosion, remove it and solder the wires together.

Stators, either a phase burns out, the last one I tested had a break in the wire just before the windings.

Testing -run the bike up and test between the three yellow wires from the alternator and earth with a multimeter, the one I did showed two of the wires had voltage the other had almost nothing.
If one doesn't match the others it the stator.
Ended up with a aftermarket one from eBay, not hard to do as it was bolted to the cover not inside the flywheel

trickywoo

13,143 posts

247 months

Monday 25th August
quotequote all
You can’t trust the optimate to show the battery condition. I had a completely goosed battery that an optimate 3 was saying was good.

Before you start throwing parts at it get the battery load tested.

Most places that sell batteries in I’ll have a tester although they are likely set up for car batteries so probably worth checking on the phone before you travel.

Once you know the battery is good you can then measure the charge going into it with the engine running. Should be around 14v +\- depending on revs. If it’s more or less it would suggest a reg/rec issue.

You can then either look closer at the charging system or just throw new parts on. Quite likely it’s that on a Honda of that vintage.

TorqueDirty

Original Poster:

1,647 posts

236 months

Monday 25th August
quotequote all
So a quick update before I have to get all grown up with the miltimeter.

Battery voltage is about 12.4 V when the bike is not running. (after 12 hours on the optimate charger)

When running with the lights off it is about 12.2 V, with the lights on it is 11.8 V

No idea if this is of any help or even relevance in terms of diagnosing what is going on?

Gaz Said

2 posts

7 months

Monday 25th August
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TorqueDirty said:
So a quick update before I have to get all grown up with the miltimeter.

Battery voltage is about 12.4 V when the bike is not running. (after 12 hours on the optimate charger)

When running with the lights off it is about 12.2 V, with the lights on it is 11.8 V

No idea if this is of any help or even relevance in terms of diagnosing what is going on?
I'd expect to see 12.6-12.8v after a day on a tender (although tenders are overrated in my experience)

11.8v with somethings on suggest it is not great.

Even if you do replace the battery, be aware these 90s/00s Honda's can have failures of the charging system that link together - e.g. a mates vfr800 had the battery go, due to a duffed reg/rec and a few weeks later the generator. Once sorted it was no bother again.

TorqueDirty

Original Poster:

1,647 posts

236 months

Monday 25th August
quotequote all
Thanks for the useful replies so far guys.

Yes, I'll read the Haynes manual today and see if I can track down the fault. I might just but a new battery and reg / rec anyway.


Rick448

1,706 posts

241 months

Monday 25th August
quotequote all
On my old Blackbird I had a nightmare with his kind of problem. All the above were tested and changed. It turned out to be a goosed starter solenoid, Easy to check and worth looking at I’d say.

the cueball

1,556 posts

72 months

Monday 25th August
quotequote all
Same thing just happened with my VFR... although the regulator connected has melted, so I'm thinking that's the issue..

Got a new one from Ultimate rectifier, new battery and a decent used starter solenoid just in case it's done any other damage.

Bike is with the garage now as I can't be arsed dealing with it, he said it's the 6th bike in 2 weeks to have the same issue...

trickywoo

13,143 posts

247 months

Monday 25th August
quotequote all
TorqueDirty said:
Battery voltage is about 12.4 V when the bike is not running.
Battery is scrap. Whether or not that’s the top and bottom of the problem depends on readings with a new one installed.

TorqueDirty

Original Poster:

1,647 posts

236 months

Monday 25th August
quotequote all
Well that is odd.

Just started following the fault finding process and the first thing was a leakage test. Haynes manual says to test the current flowing between the -ve battery terminal and the disconnected -ve battery lead. Current should not be more than 0.1mA.

First test: Current was exactly 1mA, so 10x what the upper limit is.

So I then unbolted the reg / rec and as it did so a ring terminal connector with a broken wire fell off when I took off the first bolt - so it may have been pressed against the chassis by the nut the held the reg / rec in place, or just resting against it and it dropped out when I moved the reg / rec. No idea what it was originally connected to. Can't see anything obvious.

Anyway, bolted the reg /rec back on and repeated the leakage test and now the reading is 0.00mA. Bizarre.

Next I checked the battery voltage with the ignition off. 12.6v. The started the bike and it dropped a bit, but when I revved it to 4000rpm the voltage went up to about 14.4 V, which if I understand correctly is what is should do if the reg / rec is OK and the stator is working.

So could it simply be a shagged battery and the mystery ring connector is a distraction?

Going to test the alternator wiring next.

TorqueDirty

Original Poster:

1,647 posts

236 months

Monday 25th August
quotequote all
Well everything else seems to check out so new battery ordered and hopefully it will be that simple.

Still puzzled by the leakage test but maybe I just messed up the first effort.

Time will tell.

TorqueDirty

Original Poster:

1,647 posts

236 months

Tuesday 26th August
quotequote all
Contributary fault identified.

I adjusted my back brake lever a few weeks ago and yesterday when I was doing the electrical tests I realised that the brake light was permanently on. I forgot to adjust the rear brake light sensor when I moved the lever! Doh.


OutInTheShed

11,905 posts

43 months

Tuesday 26th August
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trickywoo said:
TorqueDirty said:
Battery voltage is about 12.4 V when the bike is not running.
Battery is scrap. Whether or not that’s the top and bottom of the problem depends on readings with a new one installed.
The battery may just not be fully charged.

I would start by checking out the battery, charge it properly at 14.4 Volts for 8 hours or more. If it then cranks the bike and will run a headlamp bulb for 20 minutes, the battery is not the problem.

But a sickly battery may lose a lot of charge overnight, or a bike with a problem may draw current from it.

One a bike is running, a battery can be very weak and the bike will keep running.
There are some exceptions to this, like a few older Ducatis which don't have the alternator power to run the headlight unless you're speeding!
A few people came a cropper with aftermarket fuel pumps which drew a lot more current, also if you let the fuel filter block, the pump draws a huge current and the battery goes flat!

When the bike is running, it should have >14V on the battery, it should maintain this at anything above tickover with the lights on.
The factory manual may include a specific test for this.

A great many problems are bad connections. One bike I had, the main problem was a corroded fuse.

Alternator coils are pretty robust.
Regulators a bit less so, but I wouldn't go buying a new one without checking all the wiring and connectors first.
Regulators can be a bit hard to test, certainly a challenge to explain a foolproof test by forum. Trying a known good one is the easiest way.
But some regulators may blow up if the battery is out of circuit, so check the connections first.
And check all the earths!


trickywoo

13,143 posts

247 months

Tuesday 26th August
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OutInTheShed said:
trickywoo said:
TorqueDirty said:
Battery voltage is about 12.4 V when the bike is not running.
Battery is scrap. Whether or not that’s the top and bottom of the problem depends on readings with a new one installed.
The battery may just not be fully charged.
I should have quoted the whole thing in my reply but the guy said it was 12.4v after 12 hours on a charger.