I have a 99’ WR400 with a stock exhaust system. I would like to change the head pipe to a later model, so the oil filter can be removed without removing the head pipe. Does anybody have a late model head pipe or complete stock exhaust system that will fit the stock 99’ for sale? I’m not sure if the 01’ head pipe would mate up with the 99’ exhaust pipe and muffler.? But if it will that is what I'm looking for.