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2015 250fx stalling on jump landings

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The last few rides my 2015 Yz250fx has been dying on me.  The first time I unloaded it from the truck and the estart didn't work, so I kicked it and it still wouldn't start. The entire electrical system is dead because the fuel pump doesn't prime, the power tuner won't connect with the ecu. Yesterday at a GP race it died on me twice as soon as I landed a small table top jump. Took about 30 seconds of sitting and then it came back to life and started right up. 

I pulled the bike down yesterday and put dielectric grease in all the connectors, inspected for broken wires, cleaned battery connections (looked ok to begin with), and checked condition of the fuses. The only thing I found was a shoddy clutch switch elimination which I fixed, but looking at the wiring schematic I don't think would cause my problem. Anybody have ideas or similar problems in the past?

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My first though is the battery. Have you measured the voltage (engine off, engine cranking, engine on)?

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1 hour ago, Bricktop72 said:

The last few rides my 2015 Yz250fx has been dying on me.  The first time I unloaded it from the truck and the estart didn't work, so I kicked it and it still wouldn't start. The entire electrical system is dead because the fuel pump doesn't prime, the power tuner won't connect with the ecu. Yesterday at a GP race it died on me twice as soon as I landed a small table top jump. Took about 30 seconds of sitting and then it came back to life and started right up. 

I pulled the bike down yesterday and put dielectric grease in all the connectors, inspected for broken wires, cleaned battery connections (looked ok to begin with), and checked condition of the fuses. The only thing I found was a shoddy clutch switch elimination which I fixed, but looking at the wiring schematic I don't think would cause my problem. Anybody have ideas or similar problems in the past?

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What does the clutch switch do?

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57 minutes ago, DaveCR said:

My first though is the battery. Have you measured the voltage (engine off, engine cranking, engine on)?

Yes it's a shorai (spelling?) lithium battery and measured 13 volts not running. When it isn't acting up it cranks very well. 

23 minutes ago, BushPig said:

What does the clutch switch do?

Prevents the starter from being used unless the clutch lever is pulled in (or trans put in neutral via neutral switch) but since I have a rekluse it's bypassed. 

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4 minutes ago, Bricktop72 said:

 

Prevents the starter from being used unless the clutch lever is pulled in (or trans put in neutral via neutral switch) but since I have a rekluse it's bypassed. 

A riding buddy of mine had intermittent issues with his CRFX. E start and everything went dead. Pretty sure he said everything was powered up by one big relay which went out. Will see if I can find his thread it may give some ideas to run through.

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1 minute ago, BushPig said:

A riding buddy of mine had intermittent issues with his CRFX. E start and everything went dead. Pretty sure he said everything was powered up by one big relay which went out. Will see if I can find his thread it may give some ideas to run through.

This does have a main relay, and it's one of my prime suspects because the entire electrical system goes dead. If it were just the starter I could deal with it mid race by kicking. 

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9 minutes ago, Bricktop72 said:

This does have a main relay, and it's one of my prime suspects because the entire electrical system goes dead. If it were just the starter I could deal with it mid race by kicking. 

I must have confused the thread he made with a phone conversation. The thread pertains to dual sport wiring, however he had issues with the main power of that bike also, which I think was a dicky relay AND shorts due to poorly insulated wires. Which he hasnt documented on here. Yet anyway. 

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I also had it act up Saturday when I was practicing. I had a very low speed get off on a rock ledge and the bike died as soon as the left bark buster hit the rocks. Obviously the jarring is causing a relay to open, a wire to short or something similar. 

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That type of get off will trip the lean angle sensor. I haven't dug deeply enough into the manual to see how it resets....

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Post up the schematic and I can trace it out. The best I can remember helping someone else here is that circuit may be activating small relay that feeds solenoid relay. If small relay is energized full time due to your bypass it could be going out....

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2 hours ago, DaveCR said:

That type of get off will trip the lean angle sensor. I haven't dug deeply enough into the manual to see how it resets....

Was seeing that in the schematic but no explanation of how it works. I need to dig in the manual a bit deeper. 

1 hour ago, Red800rider said:

Post up the schematic and I can trace it out. The best I can remember helping someone else here is that circuit may be activating small relay that feeds solenoid relay. If small relay is energized full time due to your bypass it could be going out....

This is a very good and plausible explanation. I will take a photo of the schematic when I get home from work. 

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Ok I checked all of the relays tonight after work and all were clicking/closing properly, and had good continuity on the control side when energized. I did find a slight discoloration and some corrosion on one pin of the main relay, and it happens to be the power wire coming from the main fuse. I'm thinking this is the source of my problem. I'm going to clean it up, apply some dielectric grease and test it. 

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Edited by Bricktop72
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Well that didn't fix my problem. Put it back together enough for testing and it wouldn't start. I pulled the main loom apart to inspect and now I'm doing the wiggle test while hitting the starter button. I'm getting it to act up, but not consistently and still have yet to find the smoking gun. 

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Ok I think I'm on to something. I found I am able to get the bike to act up then start fine by wiggling this section of the harness. It's called a joint connector and just has a metal plug that splits power to the other 3 wires. Power is fed from the main fuse/relay and is split to the ignition coil, fuel pump, injector, tuning connector, and starter relay. There are no external signs of damage to any of the wires, but when I wiggle them with my meter on reading resistance it goes from 0 ohms to bouncing all over the place. Thinking I might have internal damage?

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13 minutes ago, Vintage Not Pimpage said:

You can pull the pronged plug thing off the end of it. Have you done that and had a look at the condition of the contacts ? 

Yes I have, and it's been greased as well. I just ran a jumper straight from the battery to the pronged plug to give it a known good source of power and it's still doing the same thing. 

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I think I have this fixed. After many hours of chasing wiring, and meter readings I found the terminals on that joint connector had lost tension and were not making good contact with the metal spade on the top. I removed each terminal individually and closed them up a bit and inserted back into the connector. As of right now I can't get it to act up while wiggling that section of harness, so I'm going to reassemble the bike and test it out. 

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