1984 xv 1000 yamaha

[OLETROG]

Im new to this ,my front spark plug is miss firing ,(back firing),but when i pull the cap off the plug just a little when its runing it runs fine, push it back on and it missfires again.new ngk 7 are new.

[Razorback]

Originally Posted by OLETROG

Im new to this ,my front spark plug is miss firing ,(back firing),but when i pull the cap off the plug just a little when its runing it runs fine, push it back on and it missfires again.new ngk 7 are new.

Welcome to the forum! Sure sounds like a bad plug! But if its new the only other thing that I can think of would be to check the plug wire and make sure it is in good order! by pulling the boot back like you did makes the spark build to a higher KV to jump the gap created, so could be a bad wire. Does the plug look wet and black?

[yamaha 2006]

bad plug or bad plug wire i had 750 yamaha that was shorting out because or bad plug wire check it out