I saw this spark plug on display at GTMax Motor at Shah Alam with the great red packaging that is unusual compared to the yellow box normal NGK spark plug packaging.
This NGK Yamaha spark plug is much more expensive compared to the normal NGK spark plug. This one cost at MYR8, whereby the normal NGK B8ES is just at MYR5. The red packaging really attracts my attention here and with the parts number that relates to the RX-Z model of 5BU and 5XK, I really think that I have bought a correct spark plug for my Yamaha RX-Z.
When you ask to get a spark plug for your RX-Z, the shopkeeper usually handed you the BP8ES, which can also be used . But sometime, you might also get BP7ES or even BP9ES. The different number on the spark plug relates to the heat transfer of the spark plug to minimize the carbon deposit that usually stuck at the spark arcing area of the spark plug. I have wrote a little bit about NGK Spark Plug Reference Model for Yamaha.
13 more close up pictures after the jump