I'm making this post because today I installed my new exhaust system with the help of a friend that I'm really glad was there with me because a simple pipe and muffler with one sensor connected to it became a lot more that that. I noticed I got about a half turn on the o2 sensor and immediately it got tough to turn. So I googled it and found that I wasn't the only one. I saw that someone else had had this problem and it was stripped/crossthreaded from the factory and they tried to warranty it and ended up biting the bullet and buying a new one. I was thinking to myself okay whatever a 40 dollar sensor..... but no $238!!!!! For a little o2 sensor on this tiny bike. If you're lucky like we were we went to our local hardware store and they had a 12x1.25 die and we were able to get it re threaded and got it in the pipe! This is ridiculous that Kawasaki is ripping people off like This a brand new bike shouldn't come with poorly tightened materials especially expensive sensors. I've never heard of such and expensive o2 sensor. So before you let Kawasaki take advantage of you and buy a new sensor try using the die mentioned above and re thread it. It worked for me and I hope it does for you.