Thanks every one, about the tank repairing, it is surely due to rusting and they are not coming out one time unfortunately. After repairing one hole, another hole came out the next week as a result of chemical rust remover activity, and this is the reason of taking more than three months. I have closed one needle hole two weeks ago and hopefully this would be the last.
After confirming no more leaking, I will apply tank sealer as final parmanent coat. Ordering another tank would be the last option which may request repainting of all.
50's Honda Dream was long long time ago and I just know their name only.sorry
Thanks for communication.