I'm guessing the same as most other bikes... under the gas tank.
take a look at this video
http://www.youtube.com/watch?v=Ct31s5JNhyM
The spark plugs are located under the gas tank and under the...
The plugs are good to 100,000 miles and should be replaced with AC Delco iridiums. They should come pre-gapped to .040" and care should be taken to not disrupt the protective coating on the plug...
I had to lift the gas tank up about 4 inches then support it, or have someone help you hold it out of the way. Use only the sparkplug socket from the bikes tool kit, because any other sparkplug...