99VFR Honda dealer sold me CR8EH-9. The service manual says CR9EH9. Are there any issues with the hotter plug?
That spark plug is designed for an engine running in colder climates. If you live in a state with really hot weather and ride hard, I wouldn't use it . Of course you could try using one in your rear cylinders for a while and see how it looks after a ride and compare it to the other cylinder with the stock plug. If it's too hot a plug it will be very white as opposed to a light chocolate brown. The 8's were fitment for my 3rd gen. but the 9's are fitment for my 4th gen. Personally I'd take them back and get the plugs that Honda recommend.
