Last year I bought a new 19 GTX 155. With less than 20 hrs. on it , I was never impressed with the performance and it was a pig on gas. Today I pulled her out of it's winter cocoon and pulled the plugs out. All three look the same with a very white porcelain but the negative electrode has a GREENISH hue to it. I don't know how to read this. Is she running to lean ? I've never been a big fan of NGK plugs sense my Hodaka days. ( that's a dirt bike from the 70s ) Anyway is this color normal or should I head for the dealer ?