Since I already had one piece of it, I thought those two hours were enough to change the gas valve 600 to that aluminium retro piece, instead of the manufacturing chromed, abs plastic one.
 
The gas valve of this Honda Shadow 600 is exactly in the middle of the petrol tank, so it was very complicated to bleed one lever to it's left side. I could do it by the dint of very hard screw fixers, and by piecing together 8.8 hard, M5 screws. The time was exactly enough or to be precise even the half of the time was enough, because in the second hour I was just sitting and watching my Shadow, which is super bike even in semi-finished condition.