In the USA, or "colonies" as some would say

, the warranty is good regardless of whether the dealer does the service or not. Do yourself a HUGE favor and get the service manual. You can get it for $40 from the dealer or online at helminc.com. You can also get it cheaper from other sources online.
Adjusting the valves is incredibly easy. I've never adjusted a valve before until i got my PCX. Do a youtube search for adjusting honda valves. Taking off all the plastic bits to get to the valves is harder than adjusting them, although, overall the entire process is easy, just time consuming. The only special tool you need is a feeler gauge which you can get at any hardware store for $5. The service manual mentions using some kind of special wrench, but that is not necessary.
Also the owners manual suggests service intervals every 2500 miles but if you look closely it is only for inspection purposes. The only time you actually need to do anything is oil/spark plug changes every 5k miles and the drive belt every 15k miles. I personally only do the inspections every 5k miles. Mostly because in the summer i sometimes ride 2500 or more miles a month.