2000 Suzuki RM 250 is driving me nuts?

Ok, I got this molested bike from a friend,im trying straighten it out for him ,so far ive replaced the crank seals and disassembled /cleaned carb inspected reed and intake boot, yet it still Seems to be running lean like it has a crankcase leak(no I did not pressure check case) ,its very tricky to get a handle on this because its running soo poorly,when it does run it will surge up to 7 or 8 k rpm ,adjusting and moving choke and idle/air screws don't really have an affect .. when I blast it up and down road it runs ok ..please any techs/people with ideas it would be appreciated !