How come that an SMF installed forum haven't indexed despite of 1000+ post/page only 16% have my site indexed by google. Are there any reason regarding with it?or any suggestion to have fully indexed nor with a higher percentage.
Having 16% of your pages indexed is not bad for a forum IMO. Just because I have 500000 pages on a site does not mean that Google will or should index them all. My guess is that very few of those forum pages have inbound links from other sites.
Forums have a lot of duplicate content, same questions being asked over and over.. Many people cross post their queries in multiple forums too. It will be difficult to get all your pages indexed. Make sure you have an RSS feed setup that SEs can crawl.
Also, how active is your forum? That can play a role too for how much/how quickly you get indexed. Take the SA forums for example, they are massive but they get indexed heavily and quickly.