Hi again guys! Just recently posted another thread about my bike not running properly. Tried to change the spark plugs today and was only able to successfully get two off. The back left plug was a dream! Super easy off and on. Once I tried getting the back right one off, it was abnormally hard to get off. I mean REALLY hard to get off. Once I managed to get it out, the new spark plug only goes in maybe a fourth of the way in using hand tightening. And when I use a tool it gets super tight before it’s even halfway in. I threw in the towel and left it for another day. Any suggestions or ideas on what this issue is/how to fix it?