I'd like to know the intake and exhaust valve clearances if someone has them handy for a 78 xs 400. Also I can't tell what TDC is for both cylinders, because when I take off the points cap at the top of the left cylinder there is a mark on the thing that spins and the thing that doesnt next to it and when I line them up I dont know which cylinder is at TDC, and don't I need to put each one at TDC indivigually? Not sure how any help appriciated.

The valve clearance for a 1978 xs400 is Inlet = 0.08 - 0.12mm ( 3 - 5 thou ) Exhaust = 0.16 - 0.20mm ( 6 - 8 thou ).To get the cylinders on the correct stroke you need to take of the alternator rotor cover which is held on with four allen bolts on the LH side at the front of the gear lever.If you turn the crank with the centre bolt you will see the marks RT and LT and a fixed pointer at 12 oclock .The LT is for the LH side cylinder ( as you are sitting on the bike ) and the RT is for the RH side. Turn the crank anticlockwise till the LT lines up with the pointer at 12 oclock then make sure you have movement on both rockers, if not turn the crank 360 dgrees until the LT lines up again and you have movement on both rockers on the LH cylinder. This is where you set the valve clearances. Repeat for the RH side useing thr RT marks . Hope this helps .Tony.