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Discussion Starter · #1 ·
'94 900SS, was working perfectly for a while since battery was charged, but now is intermittent again. Turn it on and off 5 to 25 times and it might fire up. Ignition switch or relay?
 

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My first guess would be the ignition switch. Does your bike spend the majority of the time outdoors in damp or wet weather? If so corrosion at the terminals or even internal corrosion at the contacts. Time to get out a multimeter and check for continuity through the switch. If it checks good get out the wiring diagram and start looking downstream from the switch. How are your battery and frame grounds? Condition of your positive wires and terminals to the start relay and starter? The small two wire connector on the starter relay can easily come off or loosen.
 

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So just to verify...

when you turn the ignition switch the bike sometimes does not turn on the electrical power to the bike?
or
lights come on but it will not start?

If there are no lights coming on then look at the main power relay( yellow usually) first and then the ignition switch itself.
If the lights are coming on but the bike does not start try holding the start button on and toggling the right hand kill switch on and off.
 

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Excel Addict
2001 900SSie
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So just to verify...

when you turn the ignition switch the bike sometimes does not turn on the electrical power to the bike?
or
lights come on but it will not start?

If there are no lights coming on then look at the main power relay( yellow usually) first and then the ignition switch itself.
If the lights are coming on but the bike does not start try holding the start button on and toggling the right hand kill switch on and off.
The above is important.
That attachment shows where voltage should be present with various combinations of the key, stop/run (kill) switch and starter button.
 

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Discussion Starter · #5 · (Edited)
So just to verify...

when you turn the ignition switch the bike sometimes does not turn on the electrical power to the bike?
or
lights come on but it will not start?

If there are no lights coming on then look at the main power relay( yellow usually) first and then the ignition switch itself.
If the lights are coming on but the bike does not start try holding the start button on and toggling the right hand kill switch on and off.
Nothing. Dead black nothing. When it lights up, everything is at full bright immediately. No flickering, no question, and the starter runs strong, lights dim very little. Starter hardly turns before the thing is running, even cold.

My first thinking was a contact in the ignition, but it's really "all or nothing" and usually key "jiggling" will change that in my experience. It does nothing here. Power stays full on, nor will it flicker the lights if it's black.

The relay makes the most sense since it doesn't seem to be the switch. If it doesn't energize, you get nothing. I'll tear in some more this weekend and check out the relay and poke in places with the DVM
 

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Discussion Starter · #6 ·
The above is important.
That attachment shows where voltage should be present with various combinations of the key, stop/run (kill) switch and starter button.
Thanks, that's handy
 

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Thanks, that's handy
Just remembered I had done this for VIJ from memory.

It shows the key switch connections for 3 models, including the carby 900.

Whatever you do DO NOT spray graphite into the key assembly as it conducts and will probably F up the switch.
 

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Discussion Starter · #8 ·
My first guess would be the ignition switch. Does your bike spend the majority of the time outdoors in damp or wet weather? If so corrosion at the terminals or even internal corrosion at the contacts. Time to get out a multimeter and check for continuity through the switch. If it checks good get out the wiring diagram and start looking downstream from the switch. How are your battery and frame grounds? Condition of your positive wires and terminals to the start relay and starter? The small two wire connector on the starter relay can easily come off or loosen.
I think it spent some time outside under a tarp, but I can't verify. I've owned it for a week.

If the switch were sketchy, I would lean that way, but it's "all or nothing." Full power to all when it contacts, which leads me to suspect the relay more so. Starter hits strong if the ignition powers, no hesitation at all. My ST4S should spin that hard.

I'll dig in this weekend and we can resume if nothing shows up as questionable.
 

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to test the switch just unplug it and jump the terminals on the harness side, if it works 100% of the time you have a switch issue. If it still is acting up then look at power flow getting to the switch (yellow relay).
 

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ignition issues

on this same subject I have an issue with my bike not starting off the bat, it's a 2005 749D. it does start but i have to push down on the button for longer then usual meaning I used to be able to push the button then walk away and let it start on it's own. now when shes warmed up she'll start quicker, so to recap my situation: I have to push in the button for at least 10 seconds before it wakes up and realizes oh shit I need to start and after i've been riding her for a while i can shut her down and start it up like normal. I tried bypassing the ground wire and that did not work. any ideas?
 

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Discussion Starter · #11 ·
Update: I wish all fixes were this easy. Just slid the relay up and down in the socket about 5 times and have had no further issues.
 

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Update: I wish all fixes were this easy. Just slid the relay up and down in the socket about 5 times and have had no further issues.
Lol. You just learned the first lesson in fixing electrical problems on old vehicles. Unplug and replug EVERYTHING! Amazing what the removal of a little oxide in the wrong place will do.

While you're at it, it may pay to clean your earth strap mount points too (unbolt, sand clean and shiny - including sanding off the paint from the frame at the mount points. Reassemble with a very fine smear of Vaseline) - that makes a big improvement in starting.
 

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Discussion Starter · #13 ·
Lol. You just learned the first lesson in fixing electrical problems on old vehicles. Unplug and replug EVERYTHING! Amazing what the removal of a little oxide in the wrong place will do.

While you're at it, it may pay to clean your earth strap mount points too (unbolt, sand clean and shiny - including sanding off the paint from the frame at the mount points. Reassemble with a very fine smear of Vaseline) - that makes a big improvement in starting.
Not my first rodeo, new to Ducs, not to old vehicles. Just seeing if there were known issues so I didn't have to reinvent the wheel.
 
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