After all overhauling scene, I had this issue of tappets tik tik noise..
no noise at cold start but after some time irritating TIK TIK would start..
I used 10-40 castrol gtx ,(sound was there) and and then changed all the tappets (tikki- kabuli )(washed with oil)
and ALHAMDULILLAH luckily no sound of tik tik now...
use 10-40 grade oil and wait for a week or so, if it wont help then change the tappets.... (as in my case this helped)
Best of Luck