[HondaDustR]

There's only 1 TDC for cyl 1, which is where the mark on the flywheel is supposed to be. Everything else is timed to that TDC on assembly. If the cam belt is installed and properly timed, you can get to cyl 1 TDC with the cam 180 degrees "out of time" according to the cam TDC mark, but really it's just the exhaust TDC and not the compression TDC, but sill all the same as far as just the crank and pistons are concerned. When re-assembling, set the crank to cyl 1 TDC, align the cam gear to its TDC mark, and bolt everything up.

If you have the head and cam already installed and lost timing, with the cam belt off set the crank very carefully to TDC + or - 90 degrees, whichever is closer,ie you want to back the higher pair of pistons down and away from the head. This puts all the pistons mid stroke and well out of the way of the valves. Set the cam timing and slowly return directly to cyl 1 TDC. Cyl 1 piston should be comming up as you turn. If it is not, you are going the wrong way and may contact valves with pistons 2 or 3. With the crank back to cyl 1 TDC and the cam still at TDC, install the cam belt. The balance shafts should then be checked as well.

Like said above, if your aftermarket flywheel lacks a TDC mark, you should put one to prevent any confusion in the future. If you are feeling piston position through the spark plug holes, use something that's not going to scratch the cylinders, spark plug threads, or break off in the cyl (the plug hole is at an angle to the piston face, meaning the stick needs to be drawn out more as you approach TDC or it could get clamped between the psiton and the plug hole). A long philips screwdriver wrapped in duct tape works good. You can also see the pistons through the hole with a flashlight to gage what's going on.