Oil Viscoity experience

[john grinsel]

Long time Japanese standard oil, for motor cycle/scooter =10-40 was the standard-----little experience here, WalMart 10-40 has worked for me for the last 500,000 miles or so with bikes/scooters and 2 Miatas.  Never a problem But, I remember buying a new Helix (Fusion) in Japan (first year, 1990,) of alloy wheels and also keeping another new Helix in the US.  Japanese market recommended 10-30, US market 10-40-----I noticed the Japan market bike ran like electric motor at higher speeds----the US market bike on 10-40 never was/were so smooth (in total I had 4 new Helix and over 175,000 miles with them).  Parts book showed no differences in the bikes.

Now, my 2019 XTown 300I----changed oil the other day, had bottle of WalMart 10-30 on the shelf---tried it and I noticed smoother high speed running down the Freeway-----Could be only in my head but I did noticed difference in both Helix and the XTown----10-30 hurts nothing with water cooling.

[Stig / Major Tom]

Several times over the years I've heard people say they notice a difference in engine performance, and sometimes a difference in the exhaust sound,
when changing to different oils.
I don't buy it.
It would take a bunch of blind tests to convince me.
But then, why do new cars specify 0W20 oil?!....I am assuming it is to increase MPG, by lightening load on engine.
Stig

[john grinsel]

Me, no difference in engine performance, just smoother feeling going down the highway.

[CROSSBOLT]

You are probably correct, John, because I would guess the windage drag would be less with lower viscosity just like aero drag is related to an equivalent viscosity factor expressed in the Reynolds Number of a given shape. The smaller the RN, the less the drag. Small planes have a small RN will go faster than a larger plane with the same engine. Kinda seems obvious put that way, doesn't it! Well, that's the way!

[MJR]

The owners manuals have a chart of different oil viscosities you can use depending on your operating conditions. Regular automotive oil is fine as long as your bike doesn't have a wet clutch that shares enine oil. If it has a wet clutch that shares engine oil you need an oil rated JASO MA for wet clutches because modern automotive oil have additives that will damage the wet clutch. When I bought my first Burgman 650 back in 2003 those energy saving additives that cause damage were not around.