MT-07 Unknown Fuse Popped

[Shrykryl]

I did the critical error trying to jump start my motorcycle with my car, the car has an itty bitty battery(suzuki lapin) so I figured it probably didn't have the A's to pop anything. I just hit it with the ole f@#k around and find out, and I found out. Initially things were going great. I turned the key to on and had power, the trouble happened the moment I tried to start. The starter did what it was supposed to for about 1/2 a second then popped and power has been gone since. I've looked at the manual and taken a look at all of the fuses that are available under the seat. The 30A main fuse, the 1A with the two tiny wires(not sure what this was for), and the 2 fuse boxes with all of the other stuff including ignition and signal. All of the fuses looked good, so I changed the ignition and signal ones anyway just in case my eyes are busted. Hooked up a real battery charger and nothing is happening. Are there any other fuses hidden away in the MT-07? Next step is to just eat the cost and contact my local Yamaha shop. Wife is already mad at me, help! 

[Triple Jim]

It's not the amps that the car battery can supply that causes a problem, it's the volts that the car's alternator supplies if the car engine is running.  If the car's voltage reaches the setpoint of the motorcycle's regulator, and if the motorcycle has a shunt type regulator, that regulator tries to shunt current to ground to lower the voltage.  That doesn't go well, since the car's alternator is capable of a lot of current. 

If this is what happened, I'd expect the motorcycle's regulator may have a problem.  When you say "power has been gone since", do you mean power to the starter, or power to everything? (dash not lit, etc.)  When you said the starter "popped", do you mean you heard a popping noise?

Edited August 14, 2023 by Triple Jim

[ElGonzales]

Was the car engine running?
A car battery should easily be able to start a motorbike engine even if it's standing alone next to the bike  

[Shrykryl]

@Triple Jim that's the thing, the car wasn't running. So I had hoped that it wasn't going to break anything lol.
I digress, the power is gone to the whole vehicle, not just the dash. Yea it popped, and sounded exactly like a fuse to me. I'll look into what I can do for the regulator.
There's a chance that the massive typhoon we just had put water in a place that it shouln't have been, but I bagged it before then and it's unlikely that a short would've happened anywhere that wouldn't pop a fuse.

[Triple Jim]

My guess is that the jump start isn't what caused the problem.

I've never heard a fuse make any noise when it blows, and I've been around a lot of blown fuses.

Edited August 15, 2023 by Triple Jim

[Shrykryl]

That's good to hear, I've found a few regulators around for under $50. I'll try and figure out how to shoot the one I have to determine whether or not it's bad first, but at least the replacement isn't going to break the bank. Is there a good schematic/wiring diagram for the 2018 MT-07 floating around here?

Edit: I found one, it's for a 2014, but should be good enough to get started.

Edited August 15, 2023 by Shrykryl

[Triple Jim]

A bad regulator won't make your electrical system go dead, it just won't charge the battery, or it will overcharge it, depending on how it failed.  When you get the bike running, you can check the regulator by measuring the battery voltage with the engine off, and then with it running and revved a bit.  It should be around 12.5 volts when off, and around 14-ish when running.

Have you started with the simplest things, like checking that the battery cables are connected firmly, and that the battery terminal voltage (measured on the actual battery posts) stays up (around 12 volts) when you turn on the ignition switch?

[crakerjac]

12 hours ago, Triple Jim said:

My guess is that the jump start isn't what caused the problem.

I've never heard a fuse make any noise when it blows, and I've been around a lot of blown fuses.

When I bought my SV650 track bike, the PO tried to jump the bike with a jump pack... hooked the leads up backwards and when the main fuse blew it made a bang.  Swapped out the fuse and the bike was good as new... or as good as a clapped out SV650 can be...