Here are some additional specs relating to 2001 Yamaha R1 spark plugs:
Spark Plug Brand:
NGK
Spark Plug Number:
CR9EK
Thread Size:
M10 x 1.25
Heat Range:
9
Spark plug caps on all models can only be removed using the special Yamaha Spark Plug Cap Removing Tool (Yamaha Part Number: YM-05839, or equivalent tool for removing automotive plug caps).
Make sure to follow these specs according to your 2001 Yamaha R1's service manual when checking/replacing spark plugs or their caps. For further information, reach out to your local authorized Yamaha dealership.