Hi, I just bought new NGK spark plug for my 2001 VFR and when I look on ngk website and forum the correct spark plugs number is CR9EH-9 but my local Honda dealer sold me CR8EH-9 telling me the only difference is the heat they produce? Is he right? Is CR8EH-9 gonna be okay for the viffer? Thank!
The heat range has nothing to do with the "heat they produce". A "Hotter" plug will keep its tip at a higher temperature due to a longer insulator, a "Cooler" plug will keep its tip at a lower temperature due to a shorter insulator. That's it in a nutshell. It used to be very important when running two-stroke bikes since they would tend to foul colder range plugs. If you run a plug that is too high in the heat range it might get so hot that the overheated plug tip will pre-ignite the gas/air charge leading to detonation and possible premature demise of the engine.
Allright Guys! Thank you very much for the helpfull replies!! I solved the problem by trading them for CR8EH-8, the dealer is at the corner so no big deal! thank again!
