Is there some definitive answer as to why? Not being a smart ***, just inquisitive.

 

From what I have read I believe oil becomes acidic. Therefore it would be better to change it before it sits for a period of time.

 

Been using Valvoline motorcycle oil 20w50 in the engine and
primary.

Mobile 1 gear fluid in the tranny. 75-90.

Usually change fluids and filter prior to winter storage. Ready to go in the spring.

 

There may very well be some truth to this, I haven't researched it or read up on it, but I'd be prone to believe a synthetic oil could withstand a couple months of winter storage.

 

I always run synthetic and have always just changed my fluids in the spring. My shed is not insulated and you never know where condensation may end up given the wide range of temps over the winter months. I find it best to flush everything out in the spring and replace with fresh fluids. Never had a problem and have owned many bikes of all brands.

 

I agree, which is why I don't see the real need to flush oils before storage then again in the spring? In any event I use Amsoil in all 3 holes.

 

Valvoline VR-1 20w50 dino in the motor, regular Valvoline 20w50 in the primary, and Mobil 1 75w140 gear oil in the transmission.

 

Change "old" oil in the fall before storage. If you're near the mileage for an oil change, you really should change before you put the bike away.If your oil only has a few hundred miles on it, leave it in. Harley owner's manual says to change oil before storage. So do numerous others.
The reason that changing before storage is a good idea is because the combustion process always has a certain amount of blowby (this is why oil gets black) this blowby causes a chemical reaction in the oil causing it to become acidic. Leaving oil in a cranckcase for months allows the acidic oil to attack seals,gaskets, etc.


"Change the oil before you store the bike. Old oil contains combustion by-products and other nasty stuff. So do an oil and filter change now that the bike is still warm from being run. This is probably the second-most important step of storage, and possibly the only one that will cause permanent damage if skipped."

http://www.clarity.net/adam/winter-storage.html

Your bike, your choice.

 

Oh c'mon one more thread wont hurt, besides, it's something to do...OP, don't believe the BS about synthetic, it's just a ploy to get you to spend $$$ on oil. If it was so great the HD factory would put it in from factory.

 

CVO's DO come with synthetic from the factory.