Hello guys,

I've been having electrical problems with my Ninja 300, even after spending over $1000 on it for previous repairs. I bought a new battery and it worked like a charm for a few days and now it won't start.

I'm having it looked at in December but right now riding my Honda CBR. Have any of you had this problem especially with the Stator? Is it expensive to replace? Just worried this Ninja will be my money pit.

Hi Guarino, first thing you need to do is fire that mechanic!

Need to separate cause vs. effect. Effect you have is bike not starting and dead battery. We’ll completely ignore that because those are not really problem. By focusing on actual problem, fixing battery-charging, then good-battery and bike-starting will be automatic. Many possible causes of battery not charging:

- broken wire in charging circuit, most often at stator plugs
- bad stator, extremely rare and not likely at all
- bad RR-regulator rectifier, very good possibility if bike was ever jump-started from running auto

So please answer some questions and we can narrow down troubleshooting path:

- has bike ever been jump-started from running auto?
- what work was done on this $1000 repair? What troubleshooting steps taken? What was results and diagnosis? What repairs done and parts replaced?
- do you have multimeter and know how to use it to measure AC & DC voltage? Resistance?

This is literally 5-minute procedure to test wiring and $40 part to replace.

You're an Angel Danno, Thank You,

I'm not too mechanically inclined especially with Ninjas, I'll speak to the mechanic about what you pointed out. I don't think it's their fault as I told them I believed it was caused by an older battery.

I bought a used Ninja 300 months ago with damage on both sides. I had the muffler, bar ends, right bar (bent), steering bearings/bar replaced, oil changed, new battery, brake pads replaced.

Im saving up for some new chinese fairings. Ill tell what the mechanic had found.

Thanks Again, I was just venting a bit, upset with myself and the Ninja.





Hi Guarino, first thing you need to do is fire that mechanic!

Need to separate cause vs. effect. Effect you have is bike not starting and dead battery. We’ll completely ignore that because those are not really problem. By focusing on actual problem, fixing battery-charging, then good-battery and bike-starting will be automatic. Many possible causes of battery not charging:

- broken wire in charging circuit, most often at stator plugs
- bad stator, extremely rare and not likely at all
- bad RR-regulator rectifier, very good possibility if bike was ever jump-started from running auto

So please answer some questions and we can narrow down troubleshooting path:

- has bike ever been jump-started from running auto?
- what work was done on this $1000 repair? What troubleshooting steps taken? What was results and diagnosis? What repairs done and parts replaced?
- do you have multimeter and know how to use it to measure AC & DC voltage? Resistance?

This is literally 5-minute procedure to test wiring and $40 part to replace.

Yeah frustrating when bike doesn’t work. Bad battery can’t cause any damage, it just won’t have enough juice to start bike. Desperate quick-fix measures used by many mechanics can cause damage though. Such as jump-starting bike from running auto. That will fry RR - regulator/rectifyer.

This might be issue with your battery not starting. Again, need to test and measure with multimeter to know for sure. Most mechanics are useless when it comes to electronics, which is why I do all my own work.

Here’s some bodywork: https://www.ebay.com/itm/162277926358

Yeah frustrating when bike doesn’t work. Bad battery can’t cause any damage, it just won’t have enough juice to start bike. Desperate quick-fix measures used by many mechanics can cause damage though. Such as jump-starting bike from running auto. That will fry RR - regulator/rectifyer.

This might be issue with your battery not starting. Again, need to test and measure with multimeter to know for sure. Most mechanics are useless when it comes to electronics, which is why I do all my own work.

Here’s some bodywork: https://www.ebay.com/itm/162277926358

Thanks again Danno,

The mechanic told me they could not find anything wrong, the charging systems work just fine. They just cleaned the connections and told me to keep the battery charging when not in use.

They just cleaned the connections and told me to keep the battery charging when not in use.

That's a good one. I can leave my 250 sitting for a couple months without charging the battery and it starts fine.

Put a meter on the battery, start the engine, rev it a little, and make sure the voltage rises from what it read before starting to something around 14. If not, the charging system needs attention.

Thanks again Danno,

The mechanic told me they could not find anything wrong, the charging systems work just fine. They just cleaned the connections and told me to keep the battery charging when not in use.

Another possibility with perfectly working charging system is you’ve got a short that’s causing parasitic drain while bike is not running. Again, very simple test with multimeter. You still need new mechanic that’s better than what you have now.

You can do a quick internet search on how to hook your meter up to test for parasitic draw, and simply remove each fuse, one at a time until your amp draw goes away. Then you know what circuit the issue is on. From there you can narrow it down to your failure.