20w50 WILL KILL THE ENGINE, If it hasnt already..
People are using 0w20 in this engine in milder climates, you should switch to 5w30 or 10w30.
As one poster told you to try 5w40 first and then 5w30, upto you to go through that route..
Or just pour 5w30 direct..
Your call.
.
But any thing above .....w30 is bad for this engine. w40 also strangulates (experieced once, was a Mistake)....
You can easily keep using 5w30 for 300,000 - 400,000+ km in this R18 engine..
You can get TOTAL 5w30 API SP (latest one) GF6 Fully Synthetic (buy from Total company operated Pump only), or visit nearest Honda Dealership for 5w30 3.7lit bottle. Liqui Moly is iffy (hard to get genuine product in Pak and nothing special in it).. On the other hand, Mobil1 oils are good (once again, if you can get genuine product)..
But Total 5w30 is enough (8000+ km Oil change interval if you use "5w30 API SP").
**Oil Filter Honda Genuine.