Below are some pictures from replacing the spark plugs last weekend. As with most routine maintenance, very straightforward. Honda recommends replacing the spark plugs every 105,000 miles or every 7 years. I’m not sure when mine was last done, but the old plugs actually didn’t look too bad.
From right to left, the following pictures are plugs 1, 2, 3, 4.
The new plugs. These are the NGK OEM Platinum plugs. The gapping should be around .4, so give them a quick check before putting them in.
Put a tiny amount of anti-seize on the new plug threads, and torque them to the proper spec of 18ft-lb.
Reinstall everything the way it came apart.