The Ultimate Comparison 10w30 vs. 10w40 Engine Oil

40 refers to it's viscosity. 10w40 would be thicker than 10w30. 40 viscosity will work just fine in the bike. It is the more popular than the 30 ... 10W30 and 10W40 are made from the same base (assuming we are comparing oils from one manufacturer) with different amounts or types of polymers ( ... Redline's 5w30 starts out with a thinner viscosity of 10.6cst at 100c, compared to it's 10w30 which is at 11.0. Also, I've seen oil analysis ... I wonder what it would run like with 2.5HSC pistons on 289 rods without any machine work to take into account the modern head gasket ... 10w30 is thinner than 15w40, meaning it flows through the engine more easily but doesn't have as high of a film strength as 15w40. RECOMMENDED ENGINE OIL QUANTITY ; Super Splendor 125, Super Splendor S.V, BS-IV, 10W30 SL MA2, 0.95 litre ; Xpulse, Xpulse 200, BS-IV, 10W30 SL MA2, 1.20 litres ... Difference between 10W40 and 10W30!! HUGE ... 10W30 vs. 10W40 Oil | What's the Difference Between 10W30 and 10W40 Oil | Partzilla.com. Definitely 10w30. As long as you are not enduro racing in the heat of the summer, 30 weight is fine. Whereas thick oil when cold provides less ... 10W40 has ten more W's than 10W30. There's a formula for it, and you can buy just straight W at any auto parts store, if you have a crankcase ... What would you expect the Honda rep to say? ;) 10W-40 is perfectly fine and comes in many brands.