I am setting up a clutch on my bike, clutch inner has a measurement from the end to the innner clutch hub to the end of the inside the output shaft has a measurement from the bearing to the end of the spline when I fit these 2 together do I set up so it is exactly the right size  or do I set up with a gap to allow for heat or do I make it a little bigger to keep it tight if big or small how many thou is the measurement as I understand it has to bottom out onto the bearing of the output shaft but if its to big a gap damage will be done to the front of the inner clutch hub was thinking 2 thou tight will support it and keep it tight maybe need more what a headache

maybe I havent erxplained the problem but am going to put extra than 2 thou maybe an extra 20 thou so that it definetly tightens up and cant miss 20 thou is about .5 of a millimeter