2020 yz450f battery problem.

Christopher Moore
Edited Date/Time 3/16/2021 6:33pm
Having a problem with my battery on my 2020 yz450... I put a brand new battery in and it died after 3 15 min motos(I’ve always ran firepower battery’s but they didn’t have one in stock so I got a skyrichpower li battery). The bike just shut off in the middle of the track. The stock battery also got drained down. Not sure what could be causing this... any information? very lost and not sure what to do now
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cloud41
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cloud41 3/15/2021 5:17am
3/15/2021 5:17am
Christopher Moore wrote:
What scares me is the bike shut off when it died
I’ve noticed this has been happening with the electric start four strokes - bikes randomly shutting off on the track.
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mx317
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mx317 3/15/2021 7:51am
3/15/2021 7:51am
Christopher Moore wrote:
What scares me is the bike shut off when it died
cloud41 wrote:
I’ve noticed this has been happening with the electric start four strokes - bikes randomly shutting off on the track.
I haven't noticed it.
sgrimmxdad 3/15/2021 9:30am
3/15/2021 9:30am
Christopher Moore wrote:
Having a problem with my battery on my 2020 yz450... I put a brand new battery in and it died after 3 15 min motos(I’ve always...
Having a problem with my battery on my 2020 yz450... I put a brand new battery in and it died after 3 15 min motos(I’ve always ran firepower battery’s but they didn’t have one in stock so I got a skyrichpower li battery). The bike just shut off in the middle of the track. The stock battery also got drained down. Not sure what could be causing this... any information? very lost and not sure what to do now
You got an electrical problem, I'd go over all the connections first and then check the stator!
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Ron_Shuler
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Ron_Shuler 3/15/2021 9:45am
3/15/2021 9:45am
Put a new battery in and start the bike use a voltmeter and check voltage at the battery with the bike started to see if the battery is being topped off by the bike sound like that might be the problem
SmokinJoe439 3/15/2021 10:32am
3/15/2021 10:32am
Usually on my street bikes when the battery dies like that it's the voltage regulator/rectifier has gone out. They are cheaply made cause running issues when they go out and it's usually a sudden change not gradually.
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ebers
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ebers 3/15/2021 5:25pm
3/15/2021 5:25pm
I’m experiencing this exact issue currently. I’ll keep you posted as I find out what I can.

Does your tuner show you an error code by chance?
mx317
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mx317 3/15/2021 6:51pm
3/15/2021 6:51pm Edited Date/Time 3/15/2021 6:52pm
Ron_Shuler wrote:
Put a new battery in and start the bike use a voltmeter and check voltage at the battery with the bike started to see if the...
Put a new battery in and start the bike use a voltmeter and check voltage at the battery with the bike started to see if the battery is being topped off by the bike sound like that might be the problem
The Yamaha app will show how much voltage it is putting out. No voltage meter is needed. Mine puts out 13-13.5v if I remember correctly. Start it up and check the voltage. It also shows coolant temp and other readings.
MX Warrior Dad 3/15/2021 7:08pm
3/15/2021 7:08pm
This is going to be a lengthy reply but I went through the same process
I replaced several batteries, the main harness, the capacitor and finally the ECU and that did the trick

If I bypassed the capacitor, it started up instantly and ran strong. My son raced it all day long.
I replaced the capacitor and same thing so it wasn't the capacitor. Replaced the harness that plugged into the ecu and still no luck. The only thing left to replace was the ECU. Replaced it and it fixed the problem

Try bypassing the capacitor and see if it fires up strong
If it does it's the ecu
Timo
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Timo 3/15/2021 7:28pm
3/15/2021 7:28pm
MX Warrior Dad wrote:
This is going to be a lengthy reply but I went through the same process I replaced several batteries, the main harness, the capacitor and finally...
This is going to be a lengthy reply but I went through the same process
I replaced several batteries, the main harness, the capacitor and finally the ECU and that did the trick

If I bypassed the capacitor, it started up instantly and ran strong. My son raced it all day long.
I replaced the capacitor and same thing so it wasn't the capacitor. Replaced the harness that plugged into the ecu and still no luck. The only thing left to replace was the ECU. Replaced it and it fixed the problem

Try bypassing the capacitor and see if it fires up strong
If it does it's the ecu
What part are you calling the capacitor? I don't know of one on my 19, just skimmed the parts finch and didn't see one listed.
MX Warrior Dad 3/16/2021 8:12am
3/16/2021 8:12am
Smoothing CONDENSER part# 187155001637
I would replace the harness and the capacitor along with replacing the ecu because the ecu is expensive and you don't know if the harness shorted out the ecu



MX Warrior Dad 3/16/2021 8:22am
3/16/2021 8:22am
We cut the plug wire off the old capacitor plugged it in to the harness and wired it directly to the battery and it fired right up. Battery was strong. We would put the new capacitor in like it should be and same battery was weak and wouldn't hardly turn over.
Ecu is just under $400, capacitor is under $100 don't remember exactly how much the harness is but it wasn't too bad.

Search my older my post on vital around October and I had a post or two on this exact problem
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