Review on K&N KN-171C Motorcycle Oil Filter: High Performance for Harley Davidson & Buell Motorcycles - Compatible with Synthetic & Conventional Oils by Brian Quenzer

I have never had a quality issue with K&N. The last time I bought it, the nut didn't end up being a specific size. I've tried every US and metric size on both sides of the advertised 17mm and none of them could grab them well enough to loosen the previously installed manual filter plus 1/4 turn of a K&N filter. I also tried different types of heads (6pt, 12pt), wrenches and whatever I could find in the allowed space. Everything will slip. I strongly suspect the nut was the right size BEFORE it was painted or chromed. I ended up having to poke it with a screwdriver and twist it a bit to unscrew it. Bad feeling in the tight space of the Harley so I wanted a K&N with a nut on the end so I wouldn't damage the crank sensor with the filter. I use the same type of filter on my truck in a much more convenient location. Hopefully the right plug will fit the next time you change it. I'll switch brands if I can find one with better quality control that offers a different means of removal than the usual filter key. Really simple and smart idea as long as the production is stable at the right level.