When removing the valve spring (to install seals), how do I ensure the piston is at the top of the cyclinder I'm working on? Do I just look to see if both valves are closed? How does that work. Also do I have to place pressure in the cyclinder if the pistion is already up???

Thanks!!!

 

If you can't trust the arrow on your crank hub (I couldn't, as mine was off), you can tell a cyl is at TDC on compression stroke by (as you said), checking to see that both valves are closed. When a cyl is at TDC compression, there will be another cyl at TDC exhaust. So, to check, for say cyl #1 TDC, look to see that both valves are closed, and that cyl #6 has the exhaust valve open.

You won't need compressed air if you get the piston at the right point in its travel (close enough to top). You should remove the valvespring and hold tightly on the valve stem as you push down to see if you touch the piston with it. If you don't feel the piston, hold onto the valve stem (or secure it) and have someone turn the crank by hand in slow increments, until you can push the valve stem down a bit and feel the piston. Once you have the piston far enough up, you can just let go of the valve stem, as it will rest on the piston (I think you knew this, but I just want to be clear).