hi
i would service it every 2000 miles no matter what it says in the book. i do an oil and oil filter change every 1000 miles on my xt660x and every second service i do the plug as well and check and clean all filters , i know thats a bit over the top. but its a big single so �30 ever 1000 miles to look after my engine is not much to pay. and on my other bikes ie fz1 & gsxr 750 every 2000 miles. hope this helps