The spark plugs on a 1999 Suzuki Intruder 1500 are located on the right side of the engine. To access them, you will need to remove the seat, the fuel tank, and the left side cover.
Here is a more detailed guide:
1. Remove the seat by pulling up on the front edge and lifting it off the bike.
2. Remove the fuel tank by turning off the petcock and disconnecting the fuel line and vacuum hose. Lift the tank up and off the bike.
3. Remove the left side cover by removing the two bolts that hold it in place. Pull the cover off the bike.
4. The spark plugs are located on the right side of the engine, just below the cylinder head. There are two spark plugs, one for each cylinder.
To remove a spark plug, follow these steps:
1. Remove the spark plug wire by pulling it off of the spark plug boot.
2. Use a spark plug wrench to loosen and remove the spark plug.
3. Inspect the spark plug and replace it if necessary.
4. Reinstall the spark plug and spark plug wire.
When reinstalling the spark plugs, be sure to tighten them to the proper torque. The recommended torque for the spark plugs on a 1999 Suzuki Intruder 1500 is 18–22 ft-lbs (24–29 N-m).
Once you have replaced the spark plugs, reinstall the fuel tank, the seat, and the left side cover.
