Electrical problem - Suzuki RF900

[2Seat_Terror]

SOLVED. See page 2.

Hi All.

Hoping someone can point me the right way (from experience?)

Came out to bike after work, turned key - no lights (dash or otherwise) and no response to anything electrical. (Was fine riding to work in the morning).

Attacked it in-situ the next day with a multimeter etc and determined the following:

12.6v at the battery
12.6v at wires going into ignition (everything still connected) KEY OFF
0.0v at wires going into ignition (everything still connected) KEY ON
12.6v at battery and starter relay terminals key on or off
All fuses OK (inc starter relay fuse (30amp))

It actually did the same thing a few weeks ago. Jumping it made no difference. I opened every plug and terminal I could find and cleaned them, and things came back to life. Tried the same thing this time - no dice.

Could the starter relay be at fault (since no volts past there with key on)? Suggestions appreciated!

I don't want to have to drive my wife's cage around any more than I need to!

[FJRider]

Sounds like the ignition switch is buggered. They do on the odd occasion ...

Get a second hand one from a wrecker ...

[jellywrestler]

Sounds like the ignition switch is buggered. They do on the odd occasion ...

Get a second hand one from a wrecker ...

he stated there was voltage going INTO the ignition with key off then none with key on at the same point. He didn't mention OUT of the switch so how could a switch cause a fault 'upstream' of it's place in the circuit.
sounds strange that it's dropping all it's voltage are you sure you metered it on the input?

[JimO]

I don't want to have to drive my wife's cage around any more than I need to!

you should get your wife a car then

[Coldrider]

battery plates opening up under load?, I've had that with cars, more than once.

[Drew]

Voltage at the ignition switch with it off, and none with it on, is fucked up. Really fucked up. I hope you repeated the test a couple times to check that result.

Umm, I would be checking the wires where they come through the frame beside the headstock on the right hand side. Could be 'chaffed' through and shorting. Turn on the ignition, and something shorts out there sort of explains the symptoms, but I would expect the smoke to get out of the wires if you left it on for more than ten seconds.

[FJRider]

he stated there was voltage going INTO the ignition with key off then none with key on at the same point. He didn't mention OUT of the switch so how could a switch cause a fault 'upstream' of it's place in the circuit.

But the key was obviously having an effect on the circuit ...

[jellywrestler]

But the key was obviously having an effect on the circuit ...

no, the key was supplying power to the other side of the key then to whatever circuits were then on line so doesn't at all mean the ignition switch is naffed.

[Brian d marge]

FROM MEMORY , ,,ie fer gwad sake dont quote me , the ignition switch and the starter relay are on the same circuit ( red wire ? )
IF the starter relay is acting up , ie when low tension side is connected, it could be shorting to earth.

I think the circuit is red , battery to starter relay to ignition switch ( low tension side )

But before you do check , clutch lever position switch and side stand switch ( both highly used and on the same circuit )

most likely as these get the most use and the side stand is exposed to crap

breaks ( tank off and WITHOUT moving handlebars bend wiring loom working ur way towards switch ) , and bad earths

finally or even firstly check ignition switch is actually switching and not sort

let us know what u find

Stephen

[paturoa]

Find a wiring diagram first!

I'd guess the battery or close by connections is the culprit. With the ignition switch off, there is no proper load and the current would be tiny (may be driving a clock or such like). Switch it on and I'd guess that the battery goes open or intrnal high resistance.

When trouble shooting lecky stuff, always start at one end. Starting in the middle is the hard way.

Switch it on and start from the battey terminal and work your way towards the ignition.

[2Seat_Terror]

Thanks for the responses.
Voltage at the battery and to starter relay stays at 12.6v ignition on or off, so i think tha battery is OK. I'm suspecting (at this particular moment) that something that is connected when the key is on has a short, and is taking down the whole lot with it.

Checked over the loom a couple of weeks ago (tank off). A few small splits in the outer covering (appears age related, no indication of chafing - no damage to insultion on wires inside. Taped up the splits)

I'm really hoping it isn't the ignition barrel itself, that appears to be a real pain to get off... given the installation instructons involve turning the bolt heads right off.

Also checked earths last time (one was on solid and I couldn't get off easily. Other one removed, checked, re-installed. Will check it still is though)

I will advise what I find (no news yet).

[Brian d marge]

Thanks for the responses.
Voltage at the battery and to starter relay stays at 12.6v ignition on or off, so i think tha battery is OK. I'm suspecting (at this particular moment) that something that is connected when the key is on has a short, and is taking down the whole lot with it.

Checked over the loom a couple of weeks ago (tank off). A few small splits in the outer covering (appears age related, no indication of chafing - no damage to insultion on wires inside. Taped up the splits)

I'm really hoping it isn't the ignition barrel itself, that appears to be a real pain to get off... given the installation instructons involve turning the bolt heads right off.

Also checked earths last time (one was on solid and I couldn't get off easily. Other one removed, checked, re-installed. Will check it still is though)

I will advise what I find (no news yet).

Don't get complicated , go to the simple thongs first, things that get used a lot , clutch switch , side stand switch then ignition
If you do pull the ignition switch apart , mark everything and take digital photos , they are full of small bits

Stephen

[BMWST?]

here is a simple one.Are the battery terminals tight and clean

[paturoa]

Voltage at the battery and to starter relay stays at 12.6v ignition on or off, so i think tha battery is OK. I'm suspecting (at this particular moment) that something that is connected when the key is on has a short, and is taking down the whole lot with it.

Unlikely there is a short to earth, as the current would be huge and things would melt.

Right, so now you know that the batt terminals sit at 12v with the switch on, and at the ignition swith it is zero. If they were connected properly it would be 12v at both locations.

So start working your away from the battery towards the switch. Find out where it drops to zero.

[davereid]

A voltmeter is a poor tool to use for diagnosis on a fault of this kind.

A test lamp is a much better way of getting to the bottom of these kind of faults as it draws a bit of current, and will soon establish the location of a poor junction.

If your battery is in good condition, it can't be "pulled to ground".

It will light a fire to stop that happening, so assuming battery is known to be good, check faulty connections and that switch barrel first.