Where to find an alternator?

[Chricks]

Hi there all,

I recently upgraded my fxr150 to a zxr250. All went well for a while until the battery started running low. I assumed it was because of the battery having sat for a while with little to no use (as informed by previous owner).

But i have since used a multi meter over the battery while off and running. Voltage reads the steady at any revs. This makes me think that the alternator is buggered.

LONG STORY SHORT: Does anyone know where i can get a replacement alternator for a ZXR250 (1989) that isn't as rediculously priced as the Baron? Or even second hand?

Thanks in advance

[Paul in NZ]

I'm too tired to type it all out - do a search on KB on rect / reg testing before you spend $$.. Chances are your rect / reg is stuffed

[GSVR]

Why not unplug the alternator and measure the AC voltage across the three wires with engine runnning . And check resistance and resistance to earth.

If you don't know what your doing you could end up buying expensive parts you don't actually need.

Any Haynes or Cymer manual for your bike will tell you what readings should be and how to check.

[F5 Dave]

. . But i have since used a multi meter over the battery while off and running. Voltage reads the steady at any revs. This makes me think that the alternator is buggered. . .
LONG STORY SHORT. .

Make the story longer. What do you mean by "Voltage reads the steady"?

It should read maybe 13ish volts if you're lucky when not running, turn lights on, how much does it drop?

Then start & it should rise up to but not exceed a certain level. Perhaps in vicinity of 14V. If it goes above 15V then rec reg as Paul sez.

What do you see?

[Chricks]

Thanks for the help so far!

By voltage runs steady i meant that the voltage was staying at 12.3v no matter what amount of revs i was giving it. (I didnt check the voltage with the lights on)

BUT, after being headed in the right direction (rectifier/regulator) i took off the tank and was prepared to do all the electrical tests but straight away found the plug burnt in place. Obviously not good. Yeh, its fucked.

Where would be the best place to go for a new one? Wreckers or a dealer?

Cheers in advance

[F5 Dave]

If it is steady then the regulator is working, ie: it hasn't blown. The voltage is however very low. I would suspect that the battery is shagged pulling it down. Or perhaps the sensor is operating through the burnt plugs. A shagged battery will put strain on the whole system.

The plug burning is not totally uncommon. Bad connections can heat up pretty hot. Yes time for new plug. Dealer won't likely have much. Is it just the alternator to rec/reg plug with say 4 wires? You could just replace these with some decent quality bullet connectors.

An Autoelectrician should be able to sort you out pretty quick. Please avoid any of those nasty nasty pre-insulated crimps one would find at Repco or wherever.

[Chricks]

The first thing i did was replace plugs. Because of mid-range loss of power. Thought it was just fouled plugs. Turned out it wasnt.

New plugs and a charged battery it went mint. For a day. till the battery went flattish again, when the problem started all over.

My ride home a few days ago saw the bike nearly cutting out every time i used the indicators and it definately wasnt running on all four. (Ended up parking half way home, taking the battery for a quick charge before being able to ride it the rest of the way).

Red baron just came back to me with $260 for a new one (apparently thats cheap). And none of the wreckers i've tried have anything. Might have to try out of town.

Even if my main problem isnt the r/r it still needs replacing, if enough current has gone through it to burn right through the wires. And i guess if its still buggered after that well there's one thing i can count out.

[F5 Dave]

ok so fix the plug & see where you're at.

If the voltage while running pulls up to above 13/14V then. . . hold on [rereads], charged battery not changed? So the battery is still suspect. If the internal resistance is high enough it might not accept a charge from the bike where it might get scared enough by a dirty great car charger.

Alternators can be rewound, but I still don't think it is that yet.

[Chricks]

Yea yea, i CHARGED the battery. The guy i bought it off, (director of a MX shop) said he'd buy me a new battery because he thought it was all good when he sold it. Im going to pick that up today (after a month of waiting).

But a buggered battery wont change the fact that its not getting charged (will it not?) I'd rather fix the r/r then replace the battery.

I recon the guy i bought it off knew about the problem too. His comment "it hasn't been run for a while so mid-range it might be a bit sluggish" never felt right. In my experience without running for a while they dont run smooth anywhere without a decent blowout. But funnily enough, the mid-range spluttering was what pointed me in the direction of the electrical problem.

[F5 Dave]

So you are getting a new battery from the guy & you can change the plug & then see where you are. As I've said a stuffed battery will affect things, the internal resistance increases & the bikes relatively puny charging system might not be able to cope. And/or the increased resistance from the dodgy connections will likely be an issue. But look, you've obviously made up your mind that you want to replace stuff before you know what the problem is then go right ahead.

[vifferman]

$260 for a new R/R is a good price. You might get lucky if you buy a secondhand one and it might last for the life of the bike, and then again, it might be stuffed when you buy it.