Turn of events - bike won't start

[Cadyfatcat]

Hey, Hoping to get some help on this:

In the summer I low sided my 94 K75 when I hit some gravel around a turn. Got the bike home but didn't ride it for the rest of the season because I had mangled my foot pretty badly. The gauge cluster is a little busted up, but this did not stop it from starting before.

A week or so ago I started the bike successfully by jumping it with a car battery. I rode it around for a bit and returned. After that I could not start again. Battery is fully charged now. I turn the key and the cluster lights come on but there is no noise from fuel pump. Pressing the starter button yields nothing. Fuses are ok.

I guess my questions are, what could this be? If it was a fuel pump or a fuel pump relay issue, would the engine not turn over when the starter was pressed? If it sounds like relay or pump, what the best way to go about testing?

Any guidance would be appreciated - Thanks

[frankenduck]

The fuel pump doesn't run until the engine turns on a K75.

Kill switch on?

Clutch pulled in?

[Cadyfatcat]

Yes, kill switch on and clutch pulled in

[grant71]

check your electrical connectors. clean them up and make sure you have continuity.

[Freelancer]

Sounds like the starter button or the right combo switch connection could be the problem...........

Before I speculate further, a couple of questions:

A)Which side did you drop her on?

B) You said the instrument cluster got banged up, "Did the ignition switch suffer any damage?".

C)Did  you take precautions when jumpstarting the bike?(Any chance of damage to the ECU?)

D)By nothing when pressing the starter button, "Do you mean the engine doesn't try to turn over nothing or doesn't start nothing?". (I ask because if the engine turns over it could be the kickstand switch.)

As far as diagnostics go, Grant71 has it right. Check to see if you are getting power to the ignition circuit and then check for continuity.

Right now, my guess would be that the problem is in the right side combo switch connect being loose or the switch/wires being the culprit. Further info would help us to have a better chance of helping you.

Hope you get her sorted out and running soon,
Freelancer

[grant71]

i seek out older doctors, lawyers,mechanics because they have accumulated a wealth of valuable experience. An older mechanic told me that if an engine splutters and then dies look to petrol. on the other hand a sudden cut out usually is an electrical problem. not a hard and fast rule.

[Cadyfatcat]

Freelancer & Grant,

Thanks for the responses

I'm going to check for continuity later today when I get a chance, any particular locations you would recommend checking besides the kill switch and start button?

A)Which side did you drop her on? I dropped her on the right side

B) You said the instrument cluster got banged up, "Did the ignition switch suffer any damage?". No, As far as I can tell the ignition switch looks fine. Anything I should check for? I assume it works fine because with the key on the instrument cluster lights and seems to function, but, it does not show indicator lights and gearbox position. Maybe it is only engaging to semi on position and not run position?

C)Did  you take precautions when jumpstarting the bike?(Any chance of damage to the ECU?)No, I did not, how would I check for damage?

D)By nothing when pressing the starter button, "Do you mean the engine doesn't try to turn over nothing or doesn't start nothing?". (I ask because if the engine turns over it could be the kickstand switch.)By nothing I mean that nothing at all happens, no engine turning, no noise at all

[Inge K.]

B) You said the instrument cluster got banged up, "Did the ignition switch suffer any damage?". No, As far as I can tell the ignition switch looks fine. Anything I should check for? I assume it works fine because with the key on the instrument cluster lights and seems to function, but, it does not show indicator lights and gearbox position. Maybe it is only engaging to semi on position and not run position?

Does this mean that you only got instrument background illumination, and no function in bmu, charge and oil pressure warning lights?

If so check that you got power at fuse #1....if not, kill switch would be the next thing to check (if all other electrical equipment functions as normal)....exept brake light which also is connected to the fuse #1 circuit.

Inge K.

[Cadyfatcat]

So as it turns out, fuse #1 was blown and I just hadn't seen the break when I looked at it. So, moving forward trying to determine why this fuse is blowing, I read another thread where @Inge K noted that there could be a problem with a bad route of the brake wire if the right foot pegs had been removed recently. I had to replace mine, the accident had damaged them.

I switched the fuse out and here's the situation: If I press the right handlebar brake lever (for the front brake), the fuse blows. If i press the right foot brake (for rear), it does not blow, but the brake light does not come on either. I check the bulb and it seems ok. COuld this indicate the problem is the routing of the wire on the right footpeg?

[frankenduck]

I'd start by following the routing of the wiring of the switch that's causing the fuse to blow.

Just guessing but if the rear brake doesn't illuminate the brake light then a short of the front may have damaged your BMU.

[Inge K.]

Then the problem is a short to ground between the front brake light switch and the BMU relay.
It could also be a short in the switch itself (not unusual).
Disconnect the switch...the connector you find under the tank, and measure if it shorts to ground.

Inge K.

[Cadyfatcat]

Ok I tested for continuity between the bmu relay and the connector before the switch, and that was continuous. Also between the other side of that connector and the brake lever connection. That was continuous only when the brake was applied. So it seems those are both ok...Where to now?

Might it be a problem with the BMU? As frankenduck suggested? Any way to test this? Or is there something else I should look into as we'll...

[Cadyfatcat]

Checked the rear brake switch and it seems like there is a short there. It's continuous both with pedal pressed and without. Going to remove it and see if I can fix the problem. But I don't really understand why the front brake was triggering the blown fuse. Could it be that the front brake activated something in the BMU that triggered the fuse to blow even though the short was on the rear brake wire?

[Cadyfatcat]

Ok I found the short, it seems as though when I had tightened the right foot brake assembly I crushed the wire we tween the assembly and the frame. Still miffed about why the front brake and not the rear was triggering the fuse though....



update: fixed the short and bike is working again, no more malfunction!

Thanks everyone for your help