I put a brush set in my OEM starter (18 EC300), but it turns out the windings were completely cooked. Local GG dealer quoted me $420 for a replacement starter along with some ridiculous wait time. Ended up ordering this one linked below which fitted fine but rotated the wrong way - easy fixed by reversing the motor housing.
Starter:
https://www.ebay.com.au/itm/KTM-Husq...72.m2749.l2649
Brushes:
https://www.ebay.com.au/itm/KTM-Husq...72.m2749.l2649