Trying to test fire rebuilt bike (need your knowledge!)

I'm working on starting a 360 after a top-end rebuild and new wiring harness (and ground-up build in general).

When I turn the bike over using leads to a 12v car battery, the wires in the loom that connect to the battery (via leads) get extremely hot after a few rotations.

The loom has a number of changes from stock including new reg/rec from Sparck Moto, led lights, etc, but those shouldn't account for the issue.

I must have something wired incorrectly, but I keep checking all of my connections and don't see why I have the issue.

The wires that get REALLY HOT QUICKLY are the ground and heavy (10 or 8 gage?) wire that runs to the solenoid. The solenoid wire is hotter.

Any initial thoughts? I'm just looking for a push in the right direction from those who are smarter than I am before turning the project over to my local shop.

Thanks in advance!

--
Mike


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...also worth mentioning: I'm trying to start the bike by jumping from the solenoid and ground wires with (maybe undersized?) leads to a 12V car battery rather than the lithium battery so I don't stress the expensive (eventually permanent lithium) battery.




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Those jumper wires are way too small.

hillsy said:

Those jumper wires are way too small.

Click to expand...

+1

Also, there shouldn't be a ground wire on the solenoid (unless you're talking about the exciter wires).

The thick cables on the solenoid should be like so:
Battery Positive Terminal -> Solenoid -> Starter Motor

This is with the starter motor wire on one stud of the solenoid and the solenoid wire on the other.

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Sonreir said:

Also, there shouldn't be a ground wire on the solenoid (unless you're talking about the exciter wires).

The thick cables on the solenoid should be like so:
Battery Positive Terminal -> Solenoid -> Starter Motor

This is with the starter motor wire on one stud of the solenoid and the solenoid wire on the other.

Click to expand...

...I can see why my previous post caused some confusion @sonreir - I could have worded my description better to describe the issue accurately. The solenoid is wired as you describe.

I realize from others that I should have been using a much heavier set of jumper wires (at least the same gauge as the primary ground and primary positive that goes to the battery).

I swapped the (8-10 gage?) jumpers with a set of automotive jumper cables, but get the same result; the heavy (red, power) wire that runs from the solenoid to the battery gets extremely hot. (Like, will melt the outer insulation on the solenoid wire if I keep cranking the motor, hot) Any additional thoughts?

Thanks again for your help!




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How long are you cranking it? It's going to get hot over time - just need to know how long that time is.


And have you re-built / serviced the starter motor?

...pic for clarity:

The red wire (including another, smaller gage positive wire to the in-line fuse that was part of your loom) is jumped to 12v car battery with jumper cables, the black (SORRY, NOT NEGATIVE) wire goes to the starter.

I had you make me a black cable for the starter so the exposed wire wouldn't stand out. My stupid brain immediately calls everything that's a black wire "negative".

Just to confirm, it is wired as you previously described.

--
Mike


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hillsy said:

How long are you cranking it? It's going to get hot over time - just need to know how long that time is.


And have you re-built / serviced the starter motor?

Click to expand...

The primary solenoid wire gets too hot to touch without burning my finger (my gauge for testing temperature) after maybe 10 seconds. I have not rebuilt /serviced the starter @hillsy.

It does seem to crank slower than it should with a charged battery. It sounds like (from your comments) that it could be a starter issue.

To be honest, I (probably wrongly) assumed that if a starter will crank a motor over, it's doing its job, but will follow that suggestion and report back.

Other suggestions or thoughts are also certainly welcome.

Thanks again to all for bearing with me and my (still) rookie questions as I wrap up my build...


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