Honda Unicorn — missing all times while riding

Address:

Thiruvananthapuram, Kerala

sir,
I took a honda unicorn a week ago(on 30/12/2011) from the first movement its showing missing while riding it does not showing pickup of
a 150cc bike. it shows large miissing when the engine is idle for 2 hours. I go to service centre they are saying that its will gone on first service
i dont think so because my friend took same vechicle and it does not showing any complaint ... please help me ..............