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Discussion Starter · #1 ·
Been fighting an intermittent issue for a long time now, and I'm essentially at wits end. Bike is a 2009 Spirit 750, the Cali version with the emissions can (VT750-C2FAC). So what happens is while I'm riding it will just die, as if I hit the kill switch. Sometimes it will give a little stumble before it dies but 90% of the time it just acts like I pulled the key out mid ride. Almost every time it dies I can flip and un-flip the killswitch and then restart it almost immediately, but today I had to pull and reinstall fuses before it would start up again. It used to do it every 10-50 miles, now I can't get to the end of my neighborhood. When it does run, it runs good. Good idle, normal power, no weird sounds or smells, totally normal.

First started after moving to a new place where the gas pumps regularly overfilled tank, so first thing I did was replace the emissions canister under the bike. Thought that did it but after a few months started doing it again.

Here is the rest of the stuff I've done:
  • Complete carb rebuild
  • replaced all sparkplugs
  • replaced every vacuum hose on the bike (some were a little cracked)
  • replaced sub air cleaners (little ones above the emissions can)
  • took apart and inspected the auto-petcock (this bike does not have a fuel pump)
  • Completely disassembled, cleaned all contacts, and reassembled the killswitch, ignition switch, ignition button, turn signal switch.
  • replaced kickstand shut-off switch
  • replaced ignition control module
  • replaced pulse generator
  • replaced turn signal relay (only relay on the bike as far as I can tell)
  • visually inspected all wires and connections. None were melted/frayed/weird, and all connections were tight and clean on the inside.

I don't know what else to do. Only thing I can think of left is to replace the coils, but that doesn't fit the symptoms. I called a shop to ask if they'd look at it, and they told me nobody is going to look at a non-harley that's more than 10 years old. I don't know what to do next.
 

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I had that happen to me. Not as long as what happened to you.
Not sure you checked that part, but I followed the positive wire out of the battery and found the contact points in the starter relay -behind the left side cover- to be completely caked with minerals and salts, including its 30A fuse and the spare one.
A new universal relay was $80 at my local shop and fit was not guaranteed. So I cleaned the contacts really well with brake cleaner, and dried them really really well! with compressed air on a hot day. Also replaced both 30 A fuses. No issues since then.
Good luck!
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Put a small bulb as a Test light with long wires connected to the black/white wires on the coils, or at the ICM to see if when it falters that power goes away.
Then you know it is from the ignition or kill switch contacs loosing connection.
 

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ust die, as if I hit the kill switch. Sometimes it will give a little stumble before it dies but 90% of the time it just acts like I pulled the key out mid ride. Almost every time it dies I can flip and un-flip the killswitch and then restart it almost immediately, but today I had to pull and reinstall fuses before it would start up again. It used to do it every 10-50 miles, now I can't get to the end of my neighborhood
Brother,
Sorry to hear this. I can tell you that, on two Hondas I've had the same issue. The first bike I had was a 2021 Rebel. It gave me fits. It only happened in one location, as I was leaving work. I wondered if some jack ass had obtained some type of emp device and was shutting me down (far fetched, I know) because I couldn't figure out the problem. I went to two shops. No answers and of course it worked fine when they were on it. I then noticed that the kill switch was loose. Hitting a bumpy part in the road would cause it to click into the off position just enough that it made it appear to be in the on position. Bike always cranked right back up if I shut everything down and cranked it right back up.. Same thing just happened on my 2019 Shadow, in the same bumpy location. I doubt you're dealing with something that simple but I know, in my case, I felt really stupid to get shut down by something so small.
 

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I had that happen to me. Not as long as what happened to you.
Not sure you checked that part, but I followed the positive wire out of the battery and found the contact points in the starter relay -behind the left side cover- to be completely caked with minerals and salts, including its 30A fuse and the spare one.
A new universal relay was $80 at my local shop and fit was not guaranteed. So I cleaned the contacts really well with brake cleaner, and dried them really really well! with compressed air on a hot day. Also replaced both 30 A fuses. No issues since then.
Good luck!
View attachment 304331
View attachment 304332

The reason I never let a pressure washer near my bikes.
 

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Yeah, but I've been saying, wet till they use the best chemical reaction of all on a computer bike.

Then wet till those posts come roaring in without using double you dee forty to wipe it down instead.

Signed,
NOLTT or oldguy
 

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Discussion Starter · #7 ·
Brother,
Sorry to hear this. I can tell you that, on two Hondas I've had the same issue. The first bike I had was a 2021 Rebel. It gave me fits. It only happened in one location, as I was leaving work. I wondered if some jack ass had obtained some type of emp device and was shutting me down (far fetched, I know) because I couldn't figure out the problem. I went to two shops. No answers and of course it worked fine when they were on it. I then noticed that the kill switch was loose. Hitting a bumpy part in the road would cause it to click into the off position just enough that it made it appear to be in the on position. Bike always cranked right back up if I shut everything down and cranked it right back up.. Same thing just happened on my 2019 Shadow, in the same bumpy location. I doubt you're dealing with something that simple but I know, in my case, I felt really stupid to get shut down by something so small.
I appreciate the reply. I'm fairly sure it isn't a loose/worn killswitch. I've removed it twice now to inspect it and clean it so I know its all good and tight. Also, I die sometimes on smooth pavement or while just coasting a stop before a stopsign, so I don't think its getting knocked around either. Thanks for the input though. Odds are its something so simple and I've thought too hard about it to see what simple thing it really is.
 

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Discussion Starter · #8 ·
I had that happen to me. Not as long as what happened to you.
Not sure you checked that part, but I followed the positive wire out of the battery and found the contact points in the starter relay -behind the left side cover- to be completely caked with minerals and salts, including its 30A fuse and the spare one.
A new universal relay was $80 at my local shop and fit was not guaranteed. So I cleaned the contacts really well with brake cleaner, and dried them really really well! with compressed air on a hot day. Also replaced both 30 A fuses. No issues since then.
Good luck!
View attachment 304331
View attachment 304332
Thanks for this! I took it apart last night and it had some junk in there but nothing like your photo. About to run to the store to buy a new fuse and see if they have any super small wire brushes I could use to sort of reface the male ends for the relay.
 

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Discussion Starter · #9 ·
Put a small bulb as a Test light with long wires connected to the black/white wires on the coils, or at the ICM to see if when it falters that power goes away.
Then you know it is from the ignition or kill switch contacs loosing connection.
This is really smart. I'm not much of an electrician, so I'll have to do some research on how to wire up tests bulbs and whatnot. Thanks though.
 

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If you have a 12 volt socket with a bulb put long wires with alligator clips and clip one wire to the black/whire power wire at the coils and the other end to ground. Tape the socket up to the handlebars.
So when there is power at the coils, the light will be lit, and you can watch it as you drive the bike.
 
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Thanks for this! I took it apart last night and it had some junk in there but nothing like your photo. About to run to the store to buy a new fuse and see if they have any super small wire brushes I could use to sort of reface the male ends for the relay.
What I did was I cut thin long strips of fine sandpaper. Folded them over the long edge. And filed the female contacts after having sprayed them with brake cleaner.
I used my car battery lead wire brush for the male contacts.
Hope you find the culprit!
 

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Discussion Starter · #12 ·
What I did was I cut thin long strips of fine sandpaper. Folded them over the long edge. And filed the female contacts after having sprayed them with brake cleaner.
I used my car battery lead wire brush for the male contacts.
Hope you find the culprit!
Gave it a try. No go. Was worth a shot thought, and it cost me nothing to try so no regrets on that front. Still wish I could figure this out though.
 

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One thing I’ve learned from computer troubleshooting. You‘re flicking the kill switch and replacing fuses until the bike runs again. One time, try doing nothing. It could turn out that it’s just the time it needs to take for it to run again. I was thinking heat issue, depending on where you live, but if it’s doing it on the same block now… and you’ve replaced most, if not all, of the main components...
 

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I took it apart last night and it had some junk in there but nothing like your photo.
If it's there, and I mean any on the pins, it could cause things to go intermittent.

brushes I could use to sort of reface the male ends for the relay.
Brush is not the fix. It's dip the whole connector in straight vinegar. Watch it bubble. Bubbling stops, it's super clean a bristle could not reach. Rinse with water, pack with vaseline, reconnect, move on to the next connector(s)
dipping both ends if possible.

Seeing the list, the crank sensor is out being new. Jobbers come back on line, so it's a connection somewhere.
 

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If it's there, and I mean any on the pins, it could cause things to go intermittent.

Brush is not the fix. It's dip the whole connector in straight vinegar. Watch it bubble. Bubbling stops, it's super clean a bristle could not reach. Rinse with water, pack with vaseline, reconnect, move on to the next connector(s)
dipping both ends if possible.

Seeing the list, the crank sensor is out being new. Jobbers come back on line, so it's a connection somewhere.
It's an electronic part. it's good or bad, Neither age nor quantity on hand have anything to do with whether or not the part in the machine is good or bad. Test the pickup coil resistance when it quits and/or when it's hot.
 

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Agree some WATT. My camp says connection drop/electrolysis/grounds, not an electrical part.

Too many new parts swapped out.
Too many times it fires off with a kill toggle?

I have to rule out the pickups and spark units being changed, because it still has the same 'exact problem', correct? Back to, 'it wouldn't help, it wouldn't hurt' dipping bullet connectors, plastic connector in the antidote of said chemical reaction.

And the only thing comes to mind about the toggle spiking, is I don't know if you said it, but someone said .7v of a spike is any arc when it disconnects. So I'm imagining a spike of that nature and a PUSH of voltage reconnecting from that spike of throwing off the guess of resistance going on flow wise, or connector to connection wise.

Say If spark unit and pickup are both used, why the same exact problem then? If all new, why the same?

Signed,
Alex, I'll take bullet connecter for 200 hollers
 

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My experience tends to lead me to think some components fail in the same way more often than not. Others seem capable of never failing the same way twice... Working on Sperry Mainframes and Peripherals taught me that, Lucent 5E phone switches re-enforced that belief... On a pick-up coil, there's not a lot of different ways to fail. And you could be right. it may be fine. Re-test it, maybe even with a hair dryer heating it to be sure. I learned the hard way assuming a part to be good just because it's new can lead you down a very deep rabbit hole. At times it would come down to taking another unit out of service and swapping components with known good ones to prove the new part is bad.
 

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I'm still in agreement with you up to a point. And that's pretty much saying the same thing about not too many different ways to fail. If I use this troubleshooting page right out of the book:

1. Connector not connected - Pretty much that's all it says. If I add electrolysis here or down the trouble tree root some?
2. Wire out of connector - Here again, that is all the abstract said on the page. Simple enough is a tug? It says out of the connector, but how far out it didn't say. But obviously, it has to start moving out at some point, right?
3. Signal out of range, short or open - There is no signal out of range when it starts all the time. There is no short, or are we'd be burning fuses? Are we chasing that fuse junction point leaving the box at both end out and centralize the problem there? There is no open, meaning, the jobber is going to go back on line and fire it off again and again? I think I'm reading this as a bulb filament. The tungsten is connected at both ends, but is open in the middle.

If I were to replace all of those components listed, and it does the same exact thing, the odds of that clearing up the same problem never leaving after all that? To me, it narrows it down to a connection. Look at the back of the fuse box?

Has this bike been washed regularly, occasionally, sits outside a lot, is parked near the washer/drier?


.
 

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You probably already checked but are both battery cables tight? And the black ground wire screwed down to the engine good?
 

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Cp, the only thing I can go back to is to trace the popped fuse loop and what is tied in at both sides out at the back of the fuse block. Catch those colors at every connection point.

Can't find the thread on another site, but the mix now is not vinegar dip, but change to rubbing alcohol and hydrogen peroxide mix. Don't remember the ratio, but start 50/50 and work either back. Pretty cool results. I'd start with 70% alcohol, the rest oxide.

And if fuse ties in with the kill or ignition loop? By looking at the back of the fuse block,, you'll see maybe piggybacked wires on the one fuse holder side? That's a lot of chase to narrow down.

And once that's established I'd have the meter probes alligator clipped at the one wire ends, start wrinkling the harness end-to-end, watching the needle drop from infinity, etc.
 
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