i guess your bike might be driven 10k km so engine is not too old
if you attracted towards 10w40 you should give it try
waise if you don't have any problem with 20w40 than whats wrong in carry on with it
Synthetic engine oils are for latest modern engines
Zic M7 is not fully synthetic engine oil its semi synthetic they add some quality of synthetic
so switching to it would not prove harmful for engine
Recently in car engine oils they changed Zic Hiflo 20w50 packing and on new packing its written synthetic
my brother has been using Zic Hiflo in cultus car since 2011 so i was worried if synthetic will prove right for
engine over 160k km drive i called zic they told me its not fully synthetic there are fully synthetic available in
zic but they are expensive and other versions this particular is just added around 20-30% quality of synthetic
some chemical are included in oils that give it quality of synthetic so its completely safe to use in old engine