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I would like to ask for your help diagnosing my bike's starting issue.

Long story short: the starter won't turn, but once I manage to push-start the bike, the bike runs perfectly. The starter sometimes turns when the engine is on. Here is a video showing what's wrong in 50 seconds.

Full story: What is the problem? When I push the start button, the lights go off, the dashboard goes off, and I hear a clicking sound (which I identified as coming from the starter relay). The starter does not turn at all, or sometimes, it makes one turn before killing the lights and not turning again.

Temporary solution that I found: Push-starting the bike in 4th gear is extremely easy. I push it to about 10km/h while in 4th gear, let go of the clutch and press the start button simultaneously. This is enough to start the bike. Once it starts, I hit the clutch really fast, and rev the engine a bit. The bike rolls perfectly after that.

Troubleshooting done so far, in chronological order:

  1. I thought it was a faulty battery. Changed the battery for a new one, did not fix the problem.
  2. I thought that the starter was broken, but it works whenever the engine is on (without needing to rev the engine). Sometimes pushing the start button kills the engine, but rarely; most of the times it turns the starter.
  3. Thought it was a faulty starter relay. Changed it for a new one, did not fix the problem.
  4. I thought that maybe the generator failed to charge the battery properly. I excluded that possibility by connecting the bike's battery to an external jump-starting battery (said external battery is sufficiently strong to start a Diesel truck). The starter still did not turn.
  5. I connected a volt-meter to the battery to see what happens when I push the start button: Voltage drops from ≈12V to ≈6V, be it with or without an external battery connected.

One last symptom I noticed: If I keep the start button pushed for long enough (5 seconds), the dashboard's clock resets to 1:00 (as though the bike ran out of battery).

Update: Found this YouTube video showing a starter problem compatible with what I am experiencing: Harely starter with a similar problem.

  • Would you guys say that this explains my Ninja's symptoms? Notably, why would the starter work when the engine is running?
  • Also, would changing the starter be a solid idea in this case? Or is it more likely to be a cable problem?
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It certainly could be something like what's happening in that Harley video (which seems to be a damaged starter motor winding).

First, definitely not good practice to run the starter when the bike is running. That could definitely damage teeth on the starter assembly or the starter clutch.

Second, it's not too difficult to pull the starter. In fact, you can even pull it without removing the side fairing! I'd recommend pulling the starter motor assembly and looking for any visible damage. I believe it's only 2 screws to open up the assembly and check the internal springs and components. If you remove the starter completely, you can try giving it juice directly and see if it spins consistently (or if there is a dead spot).

Unfortunately, on our bikes (I have the same bike), the starter clutch is behind the stator basket, and removing the alternator cover also requires emptying all the coolant, so you can't test it the same way as shown in that harley video. That said, you may have to open that up anyway to do further inspection.

All that said, it does seem like something is wrong with the starter motor, but replacing it may not solve the problem... so I cant suggest just throwing parts at it without diagnosing said parts.

As for why it seems to work when the motor is already running, that could be because the starter is not actually under significant load, or the engine spinning and running could be pushing the starter motor out of the dead spot.

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  • Thank you for your reply. I'll give pulling the starter motor assembly a go, and see where that gets me. – Tib Nov 27 '19 at 9:45
  • So, I managed to pull out the starter motor. It does indeed appear to be the origin of the problem. I couldn't get it to spin with a 12V battery, and upon opening it, I found 2 broken magnets out of 6. Video: youtube.com/watch?v=m_4T3a2lQPc – Tib Nov 28 '19 at 3:39
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    @Tib awesome! It may be possible to get just the permanent magnets ( I know you can get most of the other pieces) although they are probably factory attached to the motor housing. In either case, refurbing the motor may not last long. Your best bet is probably to find one online. Either aftermarket or used will be the cheapest, but OEM is generally the most guaranterd solution for the long-term fix. – kyle_engineer Nov 28 '19 at 4:16
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    Thank you for encouraging me to take out the starter motor. I had it replaced and everything runs perfect. – Tib Dec 15 '19 at 21:46
  • @Tib glad to hear it! Good job! – kyle_engineer Dec 15 '19 at 22:11

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