Hi fellow bikers... Arnab here.I have a pulsar 180 UG4.5, 15 months old and 7500 kms run. Engine, though not excellent I say, is in alright condition and I maintain periodic servicing. Till now I've been using Bajaj DTSi 10000 oil. I used it everytime for nearabout 3000 kms and no top ups in between. I have done frequent 100-150 kms journeys so far. Now I want to start long journeys like 500-1000 kms, one in every month. I want to switch to some better oil and I've got suggestions for some good semi-synthetic oils like Motul 5100 4t 15W50 and Valvoline premium 4T 20W50. Now suggest me which one I should go for and what should be the drain period (I avoid top ups if not urgent, since I don't like to spend money for an extra can)? Remember, I am considering long journeys and on highways I'll be frequently on triple digit speeds. Please suggest which one is VFM (Motul costs almost double of Valvoline).