Weird electrical problem

[Donnydragger]

The 2008 Ninja ZX-6R i got for cheap has a weird problem I'm not sure how to fix. When I first got it the headlights would dim whenever the turn signals were on, so I figured it's the battery or the alternator, but here's the kicker. The alternator was replaced a few months ago and I already bought a new battery and replaced it. It's still doing that, but the worst part is that even before I replaced the old battery it didn't feel like it was struggling to turn on. Where would I start with this?

 

[Hip Man]

I bet this is either a grounding issue or maybe a voltage regulator problem and since the battery and alternator are new, I'd check all ground connections and test the regulator/rectifier

 

[jo_n1n_zx6r]

I'd also suspect the same as @Hip Man since your symptoms point to a weak charging system. Since you've replaced the battery and alternator, the most likely culprit is a faulty regulator or rectifier. This part is responsible for converting the alternator's power to charge the battery and manage the bike's voltage. A bad one won't properly charge the battery, leading to voltage drops under load. It can also be a bad ground connection which is a common issue on older bikes. Try checking the main ground wires for corrosion or a loose connection as this can also cause similar electrical problems. But I'd start by testing the regulator/rectifier with a multimeter!