From Cracked
"im using platinum plugs which comes with .9 gap...n im using them as it is as company says not to alter gap as the tip mite get faulty while touchin..
shud i let it run as it is or shud i change it?
also tappets gap told on usual mannual of khyber is like 0.007-0.009 wen car is hot...but isnt it on petrol..sont u think cng wud require diff gap??
plus aftr how many kms shud i change engine oil?im usin caltex havoline 30-50...engine is in good shape cuz it was overhauled completly 26000kms b4...
n not heatup issues wat so ever"
Regarding your queries;
1. The recommended gap for standard plug (NGK BP6ES) in khyber is 0.7-0.8mm. But as you are using the platinums and one of the benefits of platinum plugs is they require less current to make it jump the gap. therefore it will not miss any spark on 0.9mm gap. if you are using a performance coil you can extend it upto 1.0mm.
2. tappet clearance should be 0.008(inlet) 0.010(outlet) on CNG/petrol while engine coolant temp >80C (HOT). For petrol only you should set 0.007(Inlet) 0.009(outlet)
3. you are talking about 20-50W havoline motor oil? for that oil drain interval should not exceed 3000km.