help with carb jets

[msRandi]

My stock main jet is a 98, So I uped it to a 100, ran it hard for 45 Km and checked the plug ( white ) not good. I still have a 102 to try, But I don't think it is going to be rich enuff. Now here is what I have done, K&N air cleaner, and cut the muffler apart pulled the last baffal and put in a bigger exit pipe still looks stock kinda. So any good ideas?

[ImEazy]

My bike has a 28mm carb that had a 98 stock main jet as well. I removed the
restrictor from the exhaust and went to a pod air filter also. Went to a local
shop and got a 107.5 and 110 main jet. I decided to try the 107.5 first and
if needed go to the 110. I had also dropped the c clip on the needle to the
lowest position with the stock jet. When installing the new main I decided to
move it back up on position (fourth down from top). After the new main the
bike starts with full choke then I immediately move the choke to half and let
it idle till warm. Turn the choke off and ride. It starts and idles tens times
better than before. No blipping of the throttle needed. After my first test run
I pulled the plug and it looks to be a tad rich. I have a forestry approved
and stamped muffler from a YZ250 that I got off of ebay that I plan to install
once I feel my welding skills are up to it. I'm hoping the muffler should put
it right where it needs to be. With the stock exhaust gutted I would say that
a 105 main would be just about right although you have to take sea level into
consideration. We're at about 1100 feet above here. Hope this helps. Sorry
for being so long winded.

[msRandi]

Thanks for help, and it dos help.