Do a search on Mechanical advance..........
Click on search, then go to advance search and use this feature to help get information with what people are talking about.............Get a manual and use that also in conjunction with answers that create questions..........
If you don't have much money then all the help needed will be give willingly and free........Just look at it this way...........the money spent on the carbs could have bought the tools to do the job and still have some left over to by some tools for the next job..............
Get a manual
Some reading
Search results for mechanical Advance
http://www.xs650.com/search/33735346/?q=Mechanical+advance&o=relevance
Search results for mechanical advance by member 5twins
http://www.xs650.com/search/33735374/?q=Mechanical+advance&o=relevance&c[user][0]=156