Charging problems

[breakaway]

Hello,

A little problem with a friend's bike (1994 CBR400RR)

I was riding it to his place for him. We get off the motorway, and come to a stop at the lights. We had been riding for about 15-20 mins by now. As soon as the revs drop, bike cuts out.

The previous owner had stated that the battery was shagged, and that it was low on fuel, so I thought that it ran out of fuel. So I quickly pushed it into a side street, flicked it onto reserve and pressed the starter button. Nothing. Starter motor doesn't even try to crank the engine. I roll start it, and bike starts up, ran for a few seconds, and then dies.

So we obtain some jumper leads, and jump the bike. Springs into life just fine. I disconnect the car battery we were jumping it off, saying "alright lets go" and just then, the bike cuts out. I figured out that if I keep the revs over 5000, the bike runs. But if I hit the brakes (causing the brake lights to come on), bike will cut out.

So we just hired a trailer from shell and trailer'd the bike to his place.

Any ideas on what it could be? Regulator? Rectifier? Stator? All above points to the battery not actually getting charged. Unfortunately he doesn't have a multimeter etc and therefore I couldn't check if the bike was actually making power. Sounds like bike is making power, but not enough (shown by bike cutting off as the brake lights come on).

Could it just be a shagged battery? I thought that the battery wasn't actually required to run the bike though.

[KoroJ]

I'd start with a new battery. It could be full of crap and effectively shorting out.

It may have taken out the regulator but not worth spending more than you have to.

[breakaway]

^ Yeah I thought as much. I'm gonna take the battery to a dude with a charger, see if it actually holds charge, and go from there.

It's also worth mentioning that the bike was apparently sitting for 8 months (hence the previous owner mentioning the shagged battery). He also said the petrol in there was 8 months old.

[johnnyflash]

^ Yeah I thought as much. I'm gonna take the battery to a dude with a charger, see if it actually holds charge, and go from there.

It's also worth mentioning that the bike was apparently sitting for 8 months (hence the previous owner mentioning the shagged battery). He also said the petrol in there was 8 months old.

yep, those seem like pretty good starting points... Check battery has acid/distilled water in it if viewable. then charge for 8 hours with trickle charger, see if it holds at LEAST 12 plus volts dc. when disconnected from bike, when in bike and running battery should sit around 13.8v dc.. If battery was completely dead originally it is possible it damaged other items, but replace fuel and get good charged.. battery in first..

[vifferman]

...when in bike and running battery should sit around 13.8v dc..

The battery voltage with the engine running should be around 13ish volts with the engine idling, and increase as the revs get up. If it doesn't, then you have a charging problem, usually the R/R but sometimes the stator.

Before you go checking that, it's a good idea to ensure all the connections in the charging circuit (plugs to the battery, earth, R/R, stator) are snug, clean, and have good connection.

The procedure for checking the charging system (to ensure you don't go 'charging' off replacing components you don't need to, or frying new components because one is stuffed) is not difficult, but fairly detailed.

Post back here if the battery charging/checking thing is not successful.

[breakaway]

Will do Vifferman.

Also, Re: Reg/rec - how much are the replacement units? I understand these units blow all the time on these bikes?

[klyong82]

Will do Vifferman.

Also, Re: Reg/rec - how much are the replacement units? I understand these units blow all the time on these bikes?

Original brand new Honda $360 and probably ex-Japan so 3 weeks to wait. Alternatively Aftermarket units about $200 from bike shops. Second hands $50 - $80. Yes common to blow up.

[breakaway]

Where would one find a second hand one? Wreckers? Do we have to get one that is made for CBR400RRs? Is there any interchangeability between makes / models?

I found several cheap auctions for "12V Regulator" on turdme, are these sufficient or a no-no?

[Paul in NZ]

If you have a multimeter you can easily test a few basics.....

The charging systems on these bikes cannot deal with a flat battery easily. HOWEVER it is pointless starting anything or changing anything without a good battery... Get it checked..... Replace it if required you can do nothing without it.

[vagrant]

^
It's also worth mentioning that the bike was apparently sitting for 8 months (hence the previous owner mentioning the shagged battery).

Thats it, battery will be shagged. Even if you can get it to take a charge, it won't hold it under load. A multimeter won't load it enough to get an accurate voltage reading. You need a "toaster" (battery powered heater) to properly test it.
Buy a new one, and hope that the shagged battery hasn't damaged the regulator/rectifier unit.
If you are leaving a battery for long periods, it needs to be cycled with a battery conditioner. Unlike a trickle charger, the conditioner will slowly charge the battery up, and then load it and slowly run the battery down, and repeat.
Extended trickle charging can lead to sulphation and/or slowly boiling your battery dry.

[breakaway]

^ That's what I was thinking, but isn't it wierd that the bike ran for a few minutes before it cut out? Also, my understanding was that the battery isn't actually required to run the bike. Once I get it roll started, it should run, right?

The million dollar question: If it's not the battery, why does the bike cut out when the brake light comes on? Shouldn't it be making sufficient power from the alternator to run everything?

Just throwing it out there

[HungusMaximist]

If you are leaving a battery for long periods, it needs to be cycled with a battery conditioner. Unlike a trickle charger, the conditioner will slowly charge the battery up, and then load it and slowly run the battery down, and repeat.
Extended trickle charging can lead to sulphation and/or slowly boiling your battery dry.

Yep, I gotta agree with him on those notes.

I don't pour distilled water into my battery cells anymore, I've started using a product that I bought from supercheap autos called "INOX- Battery conditioner".

It's a blue liquid that you pour into your batter cells and it is claimed to make your new battery last 2-3 times longer or revitalize a old battery. What it actually does, it's a liquid that stops sulphur build up and it conditions your battery to make it last longer.

I have had serious shit with my battery going flat a few months back. Bought a new battery and it hasn't missed a beat. Get yourself a new one, because you can't really test shit with a shitty battery. Also get yourself a multi-meter and buy a bottle of INOX when you're at some auto shop next time about $7-10 bucks.

[klyong82]

Get your battery sorted first before looking for a rectifier. How many km's has it done? I would recommend modifying to an aftermarket one that is larger with heat fins. The aftermarket one I was shown looked like for Yamaha R1's . The OEM's by Honda were bad design and buying a second-hand one might be semi damaged.

Alternatively you can buy one from Ebay. I bought one for one of my Fireblade years ago NZ$103 including postage took 2 weeks to arrive. Came from Germany. I got a multimeter and if you wanna drop over my place we can go thru the reg/rec testing after you sort ya battery out.

[HungusMaximist]

regulator/rectifier unit.
If you are leaving a battery for long periods, it needs to be cycled with a battery conditioner.

Hey is there a cool product (but economically price that you can recommend) on the market which charges and conditions/maintains your battery?

I am keen on getting one to plug my battery when I am away. Cheers.

[Paul in NZ]

A few observations on japanese bike electrical systems that worked with the FZR...

Start with a known fully charged battery in good condition. You are wasting your time until you do this! Motorcycle batteries are probably too small for a proper load test and I have not been able to find a small hydrometer lately (PM me if you know of one) which is the best test...

Once the good battery is fitted, start the bike and set it at a fast idle. Measure the voltage across the battery terminals with a digital voltmeter set to DC. You are looking for something more than 13V, possibly 14.5V across the terminals..

Now - turn the headlights on and check again - voltage will drop so increase the revs to about 100kph cruising revs (6,000 rpm on the FZR) and again we are looking for 13.6 V or so..

Now - if you don't get this voltage you need to figure out why...

I usually go to the alternator 1st and their are 2 major points of failure - alternators and rect/regulators..

Often you will find 3 white wires (or 3 yellow on wog bikes sometimes) and these are the 3 phases from the alternator. It produces AC so switch your digital meter to AC Voltage and measure between all the phases (3 readings) and they should all be even and around 70V AC at your cruising speed...

Turn the bike off and switch the meter to Ohms (resistence) and check that none of the phases has a connection to earth (the chassis or the engine block is OK)

If both these check out then the bike is making electricity (AC) but it's not getting to the battery.

There are 3 potential common faults. faulty rect / reg, dodgy earths, bad connections.

Testing the rect / reg is a bit trickier but usually there are the 3 phases into the thing and a one connection OUT of the thing which is the DC voltage out. These often fail because they are poorly grounded so before I throw it away I'd run aux earth straps from the engine to the chassis and check clean ALL connectors. If that fails to produce a solid DC Voltage at the battery theres a good chance it's faulty and the easiest way to prove that is a subtitution with a known working one.

The above will prove / solve MOST of your issues