83 XJ 750 Starting Issues

Hey everyone,

I am having some issues with starting my bike.
I can bump start it still, so tells me that this is probably an electrical issue. Battery is good and charged. I hear a click when pressing and releasing the starter button coming from the battery on the end closer to the back tire. Looking at some threads, sounds like this is the starter solenoid. So I have one on order. However, I did some further testing and I think I might have jumped the gun a bit.

I tried jumping the starter solenoid with a screw driver - got nothing... not even spark.
I tried connecting my trickle charger to the starter motor directly. (+) to the stud, (-) to the frame as I saw explained on another thread. Got spark but no spin.
I saw a post that someone resolved this by cleaning the stud on the starter motor because fuel leaked onto it from overflowing float bowls. So I did this and that didn't fix the issue either.

Sometimes when I am jamming the starter button in frustration, the starter motor spools up very briefly. I can't recreate this issue, seems like its completely random. So not sure what could be the issue here. Could it be both the solenoid and the starter itself? Could it be the connections on the button? But then why does the solenoid click when pressed?

I would appreciate some input before jumping the gun again and purchasing a starter motor.

Thanks!

 

This would likely mean starter, but if shorting the solenoid large terminals results in no starter spinning then it could be also:

The battery is too weak to turn the starter
The connection from the solenoid to the starter is poor and will not allow sufficient current, this also applies to the other side of the solenoid and connection to the battery as well as the large ground connection on the battery to the engine.
There is an internal problem in the starter, most commonly a poor connection between the brushes and commutator ring

There have been instances where the insulator on the starter 12V lug were installed incorrectly resulting in short to ground, but that is usually done during the rebuild process.

A trickle charger doesn't have a prayer in turning over that starter, just not enough current available

If you are getting 12V at the starter terminal lug when you hear the starter solenoid engage and the starter is not spinning then very likely the poor connection internally

https://www.xj4ever.com/starter brush replacement.pdf

Sometimes a gentle tapping on the starter when attempting to start will get it going, but that's just a sign it needs a clean / rebuild

 

Diagnosing an electrical fault from an online forum is impossible without a DVM and some readings. In your position I would be reading the volts at the positive feed to the starter, when the button is pushed. Then working backwards if there was nothing there - forward if there was 12V there (ie to the casing, just in case there is corrosion between it and the casing).
Get a wiring diagram, a dvm and some practice using it.

 

In your position I would be reading the volts at the positive feed to the starter, when the button is pushed. Then working backwards if there was nothing there - forward if there was 12V there (ie to the casing, just in case there is corrosion between it and the casing).

I have a multimeter but honestly very new to using it. Red wire goes to what I am trying to test and black goes to ground?

A trickle charger doesn't have a prayer in turning over that starter, just not enough current available

Would disconnecting my battery and jumping the starter from the battery work? Just want to rule out that the starter motor is functioning. Might also have to test the wire connection between the starter and the solenoid to ensure that is functioning correctly as well.

Will do some troubleshooting and update this thread!

 

With a multimeter set to volts is how to test wires and connections - you use your logic to decide what you should be seeing, test and evaluate. If you have 12V one end of a wire and nothing the other end you know there is a break somewhere... Practice is all it takes

 

https://electricianapprenticehq.com/how-to-use-a-digital-multimeter/

 

So I got 12 volts at the connection of the starter motor. So sounds like a bad starter motor. Is this something that could be fixed? Or do I start searching the internet for a new one?

 

It's is much cheaper to rebuild / clean the starter than getting a rebuilt replacement, and a good learning experience if it is rebuildable and you can get it done.

 

So I tested voltage everywhere and everything looked good. Got a starter rebuild kit and was able to rebuild the starter. But now, the starter does not turn over when I push the button. When jumping it, the starter turns over for a bit then stops spinning - maybe killing the battery? But the battery is at 11.46 volts.
But I get a weird sound when I push the button. Hard to describe but it's like a hum but almost a little grinding too? Not like a can of rocks grinding but almost like a low buzz. Just rebuilt the clutch while the bike was out of commission and put new oil in. Might this be a case of the oil having to circulate first? (Grasping at straws here)