Q1.Can I use car wash to clean the bike?
Yes, ofcourse you can there is no harm in it.
Q2.Can I use car wax for waxing it?If not,then which polish(specially designed for bikes) should I apply?
No polish is designed specially for bikes it all ends to how much you wana spend. Normally people buy Cosmic Wax for bikes as its cheap and shine lasts longer. However you can go for Turtle or Meguiers if pocket allows
Q3.What should I use on engine to keep it clean from mud and dust?
Well as far as polish is concerned you can use brasso or turtle chrome wax. Both keep engine shiny however there is no solution for keeping engine clean. It depends on how you ride the bike
Q4.How often should I wash+wax/polish my bike to keep it away from rusting?
Depends on climatic conditions you living in. Normally enthusiasts clean and wax thier bike in a week. However if climate is dry and no rain then detailing after 15 days is good.
Q5.Should I consider service station as an option to service my bike?
Not really, They have high pressure which causes problem in starting and other mechanical parts. High pressure water seeps into joints and later cause many problems
Q6.Should I use WD-40 on different parts(small nuts,bolts)of the bike to prevent rusting?
Yes! you can. I use WD 40 specifically for shocks as it keeps them clean and rust free and no unwanted noise
Q7.On plastic material can i use protectant spray to keep the shine and to protect it from fading?
You can use 7cf on any plastic part. It keeps it clean and protects it. Never ever use lustre if ruins the plastic