I installed a K&N filter with a HMF muffler and Dyno jet. I turned the air/fuel screw out 2 1/2 turns. I checked the spark plug and it was the color of a brown paper bag.
The muffler was louder than I wanted so I put the stock back on. I checked the spark plug and it is black, but I have great power and the throttle is very peppy.
Should I re-adjust the air/fuel screw to get back to the brown color on the spark plug or leave it alone. Does the black on the plug indicate too rich? Will this hurt the engine to run it this way?
If I should adjust the screw, which way do I turn it to lean it up and am I still looking for the brown paper bag color??????
The muffler was louder than I wanted so I put the stock back on. I checked the spark plug and it is black, but I have great power and the throttle is very peppy.
Should I re-adjust the air/fuel screw to get back to the brown color on the spark plug or leave it alone. Does the black on the plug indicate too rich? Will this hurt the engine to run it this way?
If I should adjust the screw, which way do I turn it to lean it up and am I still looking for the brown paper bag color??????