What's your battery voltage readings?

I have an 82 xjmaxim.

After two months of idling time, when I tried to start her, it wouldn't start.
NOte: Battery is <5months old and it's been connected to a battery tender the whole time.
I'm getting 12.4V across the terminals. Is this an ok battery or bad?

I also notice that the head light is off when i turned the key to 'off".

Thanks,
Rod

 

i meant, to "on" position.

 

Just reading the voltage on a battery won't tell you if it's good or bad.
Take it to your local auto parts store and have them test it for you.

The headlight SHOULD be off until the motor starts; there is a relay that provides that function. It would indicate a problem if the headlight came on just by turning the key on.

 

I get 13V across mine

 

Without the motor running 13v isn't possible & if it is running @ more than 2k it should read 14v+.

 

something like this:

Key OFF


Cranking


Running

 

Whatta guy. You musta froze your bunnies off for those pics. Or were they from sometime last year?

 

More like 18 months, Fitz & the Lt got straight As for it at the time. :lol:

 

Thanks for all the reply.
so if the ignition is set to 'ON', is the tail light supposed to be on or off?

 

I know if you turn it to "PARK" it is, and can kill your battery (don't ask.)

 

Is this true for all XJ models? If so I have a few bikes with issues

MN

 

jeez i was think it was like summer of '07 but youre right 18 months + would put it in summer of '08...

 

If the ignition is in the "on" position, the headlight should be on. I'd also check to see if you can get blinkers horn, tail lights, too.

What does your battery on an OHM meter read when you hold down the start button?

 

Also,

Are you battery connections tight?

What kind of sound do you get when you turn it over?

Crank but no start, a few cranks then nothing, clicking, nothing at all?

 

NO, it shouldn't. This indicates a very common problem, a stuck (internally welded up) headlight relay.

To the best of my knowledge, all XJs and all Yamahas of that era (including both my SR500s) had a headlight relay system that did not turn the lights on until the motor was running. It's a "latching" relay, in that if you then kill the motor, the light will stay on until you turn the ignition off again.

The purpose of this is to keep the headlight from drawing current needed by the starter, or by the ignition until the motor is running.

It's very common (one of my bikes had the problem when I got it) for the light to come on when it shouldn't, due to the rather primitive headlight relay contacts becoming somewhat fused.

MN, I think you got some bikes with issues.

 

Not all XJ's use a headlight relay. Only the XJ550's, all the XJ650 (except Turbo), and XJ750 Seca models use a headlight relay. All other models should light the headlight when the key is turned on..........

Thus when treefort says that his headlight is on when the key is turned on, he is correct, since he has a 1983 XJ750 Maxim. Same with MN-Maxim and his 1100------key on, headlight on, 'casue no relay.


Tail light (and, on Euro models, the headlight housing "mini bulb") wll be lit in either the ON or P(ark) position of the main switch.

 

Thanks for setting us straight, Len. So correct answer for original post would be no, as he has a 650 Maxim.

 

Well, the first post by Copperonly is an inquiry as to whether the headlight should be OFF when the key switch is turned OFF, and in that case, the answer is "yes, the headlight should be off when the key is turned off". And that statement is true for all XJ bikes.

Confusion typically arises with the bikes that DO use a headlight relay, since the following two conditions do or may occur, which makes people think their bike is haunted (which it may very well be, but not due to these conditions!):

1) on bikes that do have a headlight latching relay, that relay is triggered off one of the alternator stator output wires, and once the alteranator builds enough voltage, it triggers the headlight relay and allows the headlight to be lit. So.........

The system is said to keep the headlight off "while cranking", but this is poor wording and not always true because of the operational design. In some cases, you can crank the engine and get it spinning fast enough (but never actually starting the engine) to get the alternator spinning fast enough and producing enough voltage to trip the headlight relay (alternator output voltage rises as it spins faster).

This situation commonly occurs when performing a compression test on the engine, since all the spark plugs are out and you can get the engine spinning really fast. But, if you have a good battery and a really top-notch alternator/rotor and the engine doesn't fire off right away, it's possible for the starter to spin the engine fast enough to get the alternator output high enough to trip the headlight relay.

In such a case, the headlight will light even though the engine might still be spinning over, before it starts, or even if it never starts. It's because the headlight relay is triggered by a certain output voltage from the alternator, which may, under some situations, occur even if the engine never starts.

So owners of these bikes may observe situations where the headlight doesn't light during "cranking", and other times when the headlight does light while cranking!


b) On bikes equipped with a headlight relay, once the relay latches, then the only way to turn the headlight off is to turn the key switch to off. Just having the engine quit will not kill the headlight, since the only way to close the relay is to kill all voltage to it completely. In other words, once it's latched open, it's open until Voltage = 0 (at which time it closes the circuit, and the process is part "a" above begins again).

So if you've started the engine and for some reason the engine dies, and you press the start button, the headlight will remain lit "during cranking" because you never turned the key switch to off (thus closing the relay).

 

Fitz, I'll have to go back and check. The 81 650 is the only one that the headlight doesn't come on with the key. All the 750's and both 1100's as soon as you turm on the ignition swich the headlights come on. So I sould check the headlight relay on those bikes to see if the contacts are stuck? If so what is a good relay to buy to replace them with. Any after market suggestions?

MN

 

Read chacal's response two posts up. If all your 750s are Maxims then they and the 1100s are behaving correctly (NO relays.)