need some advice on what to do , out last week having great time in loads of bugs and peat conditions.this weekend my mate came around and said lets go out again so i said great but i asked him to check air filter and if it needed cleaning give it a quick clean and spray filter oil on it , i came out while he was doing this and i put the filter back in . all seems ok until i go to start it when it backfired and started to run very rough and would not rev much .it then stopped when my mate suddenly rememeber he had put tissue paper down the tube to stop crap getting , so now bike wont start and tissue sucked in . any ideas what i need to do . its only a small amount .it has spat some bits out the exhaust. any help would be good