Need Help *Solved*I have a gremlin living in my bike

Ben sIII

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So an update...

Pulled the ecu and it was nice and clean on the connectors etc. Did a valve check hoping for tight exhaust valvesforming to much compression etc and all with no joy.

But i think i have isolated the issue.

The bike wont start if i stop the engine with the side stand, or if it is parked in gear and on a slope. That is if the engine seems to be loaded against the transmission it wont start, but by rocking the engine ( rolling back and forth in gear), it will start.

Any ideas why this is suddenly an issue?
 

Motogiro

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So an update...

Pulled the ecu and it was nice and clean on the connectors etc. Did a valve check hoping for tight exhaust valvesforming to much compression etc and all with no joy.

But i think i have isolated the issue.

The bike wont start if i stop the engine with the side stand, or if it is parked in gear and on a slope. That is if the engine seems to be loaded against the transmission it wont start, but by rocking the engine ( rolling back and forth in gear), it will start.

Any ideas why this is suddenly an issue?
This sound like it's related to the neutral safety switch because of the switch's proximity to a non neutral or neutral condition but regardless of the neutral safety switch open or closed state, when you pull the clutch in the clutch switch should allow the bike to start. If this is not the case you must test the clutch switch continuity and be sure there is continuity to the starter interrupt-cutoff relay plug. If you have confirmed there is continuity, you may have a bad neutral safety switch and/or a bad starter interrupt-cutoff relay assembly. #23 on this fiche https://www.ronayers.com/oemparts/a/yam/50045603f8700209bc792f16/electrical-2

Neutral safety switch #7 on this fiche https://www.ronayers.com/oemparts/a/yam/50045602f8700209bc792f15/electrical-1 If you replace #7 get a new #9 gasket seal.

You may need to copy and paste the link URL because my browser would not take me directly from the link as posted on the forum.
 
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Ben sIII

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Thanks Cliff,

I dont believe that it's the neutral as trying to start with the bike clutch in and side-stand up will still not work until i rock the bike.

The interrupt-cutoff relay assembly has been mentioned before but the intermittency of it as well as rocking seeming to be a consistent cure makes me question this, though it had some light corrosion which i have cleaned of the pins.

The Starter really also clicks every time, as in one click as the relay switches, it is just that the starter motor doesnt kick.
 

Ben sIII

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So I just played a bit more. I'm fairly certain it's not the interrupt-cutoff relay, as if I try to stay it in gear with the stand down there is no click from the starter relay, but if it's in neutral, or in gear with the stand up and clutch in you can hear the click.

So I put a multimeter on the starter motor and it seemed to get no voltage on the first hit, but then a second hit would spin the motor, so my current thought I'd a faulty starter relay or a short in the starter motor.
But neither of these explain the engine load that seems to cause this.

Need to try this again when I have more energy.
 

Motogiro

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Thanks Cliff,

I dont believe that it's the neutral as trying to start with the bike clutch in and side-stand up will still not work until i rock the bike.

The interrupt-cutoff relay assembly has been mentioned before but the intermittency of it as well as rocking seeming to be a consistent cure makes me question this, though it had some light corrosion which i have cleaned of the pins.

The Starter really also clicks every time, as in one click as the relay switches, it is just that the starter motor doesnt kick.
For some reason I thought you had checked the starter. https://600riders.com/threads/i-have-a-gremlin-living-in-my-bike.60104/#post-650877
If you haven't, pull the starter and check the brushes and commutator. If the starter has a dead spot rocking the bike in gear could get the starter off of the dead spot as the armature gets rotated a small amount. Pull the starter....
 

Ben sIII

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For some reason I thought you had checked the starter. https://600riders.com/threads/i-have-a-gremlin-living-in-my-bike.60104/#post-650877
If you haven't, pull the starter and check the brushes and commutator. If the starter has a dead spot rocking the bike in gear could get the starter off of the dead spot as the armature gets rotated a small amount. Pull the starter....

This is on the next bit of time, it was rebuilt about year and a half ago so it was not my first concern and the issue took more than a year to poke its head up since then, but it's worth a check.

thanks for the continuing input
 

Ben sIII

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It was the starter relay.

To help someone else. The issue is you could hear a click from the starter relay but the starter motor wouldn't crank. This happened intermittently

Battery was fine.
The starting safety relay had some light corrosion, but the easy way to eliminate this as an issue is if the bike is not in setup to start, like in gear and clutch out, the starter relay wouldn't click.

To test the relay without pulling the bike apart I started taking a multimeter everywhere with me and when I was going to crank the bike I would place one prong under the rubber boot in the starter motor, and the other earthed to the starter motor body. When the bike wouldn't start I would either get ,0 bolts or maybe a light trickle but when it started it went straight to about 12v.

Changing the relay took about 5 minutes.

Thanks all for the input and help.
 

Motogiro

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Glad you solved it. Not sure you ever mentioned the starter relay click, might have helped with diagnosis.
Either way…happy riding!

Great find! Intermittent problems are always simple when you finally find them.
 

agf

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Great find! Intermittent problems are always simple when you finally find them.
yep, wiring shorts in the loom are the worst i reckon
 
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