wee wee

Hi everyone, Here is my first post hope i am doing everything properly. I have a problem with the clutch on my 2005 dt175. The clutch deosn't engage properly. When the bike is off and in neutral the wheel move freely. good. but when in gear and the clutch leaver fully pulled then the wheel make the engine turn... Its is not because of the clutch cable because it happen when the clutch leaver on the engine is fully moved forward with a plier. So what could be the problem and how could I fix it ? Thanks.