No, you do not have to .....
NGK Plug DPR8EA9
on the motor lol
0.031 to 0.035"
part #: NGKDPR8EA-9
I am not sure what to do if your Grizzly 600 Yamaha will not start. You can try taking it to a shop and having it worked on.
Spark Plug fouling is pretty common.
.030-.040
From the 98-01 service manual - .03-.04 inch (.8-.9mm)
how to change spark plugs on a 2004 Hyundai sonata 6 cylinder
on top of the cylinder head just under the gas tank.
TWO!! It's a twin cylinder motorbike.
maybe spark plug