Hero Motocorp — missing while running new splendor plus

Address:

Charummootil veedu, karimanal po, kuzhivila, Thiruvananthapuram, Kerala, 695583

Brought an new spkender plus on 27/12/2018 from divya motorcorps tvm. Now it ran only 3400 kms only. While i running once i felt huge missing. But latter its comes down. I informed diya motors and they ask me to come next day to showroom. Nextday i gave bike to them. They said there is only a issue in petrol cap, and they replaced that. But after that too bike showing little missing while riding. The service manager and technician also saying that that is common to splender. I dont think like that, inever felt sucha small missing while riding a splender. Please take an action to clear my bike's complaints