1986 K100 Newbie Battery/Start Question

[Electron]

Guten tag my fellow brick pilots.

I have recently picked up a 1986 K100 for $500.

While the tyres, forks and practically everything looks reasonable, the battery that comes with the bike (which the owner said was the battery he used), is a generic 12V 17Ah (not 19 or 25Ah as I've read is supposed to be in there). Now the reciept in the box says this battery is a couple of years old, and has not actually been in the bike for about 12 months to boot.

I have charged the battery overnight and when I turn the ignition on, all the lights work, and the bike turns over, but the battery light on the dash continues to be red and it does not fire.

I have the clutch in, side stand up, in neutral and kill switch off.

The fuel pump also does not make a noise (which it's supposed to, from what I've read). I've checked the 7.5 fuel pump / FI fuse, second from the bottom, and swapped it over with another 7.5 fuse from the fuse box (as I didnt have a new one).

Still the bike turns over, but doesn't fire. I am going to grab a multimeter today just to check the battery power. Could it be that the battery does have enough amps to fire the bike?

What suggestions do you have for me on this one?

[Zipster]

If the lights light up but the pump doesn't make a noise, I'm gonna guess at a problem with the kill switch - I got caught out visually checking rather than physically checking it a couple of days ago and had the same symptoms.

[thegingerbeardman]

I recently acquired an 87 k75c in similar shape.  Symptoms were nearly identical.  You can read about what I have found here

I hope you are luckier than I.

[Zipster]

The kill switch should be in the vertical position not to the left or right. Mine was just off centre but it was enough!

[Electron]

Thanks for the quick responses. I have tested kill switch functionality. When its on, there are no lights on the dash at all. When off, all the lights reappear.

At this point, I have neutral, hazard light, battery and oil light. When hitting the starter, oil turns off, but other lights are lit.

And gingerbeardman, I hope I do not have anywhere the same amount of drama!

For reference, I am working my way through the troublshooting flow chart on this page: http://hrsbstaff.ednet.ns.ca/bvogel/K100/download/bike-wont-start1.htm

[Zipster]

With my kill switch "on" I have lights on the dash except the BMU warning light and the fuel pump doesn't get any power. On flicking it "off" the lights remain on and the BMU light comes on and the fuel pump charges up. Mine is a K1100 but should be similar.

[Scott_]

With my kill switch "on" I have lights on the dash except the BMU warning light and the fuel pump doesn't get any power. On flicking it "off" the lights remain on and the BMU light comes on and the fuel pump charges up. Mine is a K1100 but should be similar.

If I'm not mistaken on the 75's and 100's the fuel pump power relay only energizes when the engine is turning. No "pre-charging" when the ign key is turned on.

The fuel pump relay is triggered by the ECU unit, and the ECU unit gets it's "engine turning" signal from the Hall Effect sensors on the front of the motor under the "T" cover.
The ECU uses the same hall signal to also trigger the fuel injectors as well.

[Inge K.]

The LE jetronic equipped models also build up fuel pressure for a short time before the engine turns,
at start up the signal from the starter button triggers the FI relay via the ignition ECU.
When the engine has started and the starter signal isn't anymore present...the HES is in charge.

To start somewhere....when pushing the starter button, measure if it's any power present at fuse #6.
If no power is present, it's most likely that the FI relay have not closed its contacts for some reason.
If power is present, next step would be to check if power also is present at the four pin tank connector.
At the four pin connector the green/white is 12V+ and the brown is 12V-.

[Scott_]

The LE jetronic equipped models also build up fuel pressure for a short time before the engine turns,
at start up the signal from the starter button triggers the FI relay via the ignition ECU.
When the engine has started and the starter signal isn't anymore present...the HES is in charge.

Well, I was close..... either way, the pump doesn't start till you hit the starter button, and the pump gets signal from the ecu.
Thanks for the clarification Inge.

[pfls]

From your original post, I got the impression that the bike had been sitting for a year or more before you bought it. Have you checked to see if the fuel pump is seized?

[tg4360]

First things first, get a NEW properly charged battery in there.  Trouble shooting with a suspect battery is just asking for frustration. 

If it turns and you don't hear the pump running as the motor spins, check the fuses and the tank to frame connection. They can be flaky.

It is probably worth the trouble to Just go ahead and remove the pump and filter for testing/inspection because sitting tends to allow the pumps to lock up and you might find deteriorated rubber bits in the tank from alcohol.

Check these things and get back to us.