HELLO, will fzr600 3he forks go on my 3en1 400 ? and dus anyone nead set ov 41mm forks if the 600 will fit.

As I said, as long as you have the triple clamps for the 38mm forks they should go in. I think the wheel spindle is OK but cross your fingers. The brakes could be 298mm in which case you'll need a pair of those discs because 3en1 is 285mm. Calipers are the same