suzZEE I have a 3600 as well,you need to buy a cheep funnel that will fit the same hole the dip stick cam out of and you can add from there.
the number one no, no, is do not add more than required,its the easiest way to destroy your engine.
take a look at the older postings as well if you need help.
http://old.nabble.com/YAMAHA-YT3600P-to19743124.html