Au xr6 timing

Hay guys ive got a au intech xr6 motor in my stockcar and having trouble getting timing right i have no1 piston at topdead center but having trouble with the cam mark as ive been told the the mark shoul be at 3deg above head rail and also 15deg above just cant get it to run properly any ideas

Sorry this isn't an engine I've personally worked on so I am not aware of the timing procedure off the top of my head. What I would suggest is locating a factory workshop manual for the AU and ensure you follow the steps to correctly time the engine. A quick google suggests there will be coloured links on the cam chain which is pretty typical. Beyond this there's a variety of other reasons the engine would be running poorly. What has changed sine the last time the engine was running well? Or has it ever run properly?