Hopefully, you have only tried to tune on of the cans. If you still have a can that is tuned to the original frequency they were working (???) on, try to follow the procedure on repeater builders carefully. If you get that one working, you can try to set the rods to the same dimensions as the good one a try to tune the other ones.
It is possible to get a duplexer working satisfactorily (but probably not optimally) without the proper test equipment (tracking generator, etc) but takes a lot of patience and time. I did it many years ago to a set of homebrew 220Mhz cans with an HT and an RF detector on an Oscilloscope. After several nights of tuning and graphing results I got them to work very well. If you start with a working set of cans, moving them to a new frequency is easier. It sounds like you need to hook up with someone that has a service monitor or a network analyzer. Where are you located? Maybe someone can give you a hand. 73, Joe, K1ike
