While short runs are somewhat better than no runs, it is not the best for bike longevity.
The whole fuel system is nearly self cleaning when constantly flushed by frequent operation. Condensation inside the fuel tank occurs in the air pocket of a partially depleted tank. Kept full, this condensation is minimized. Products such as Sta-Bil are also supposed to help remove water from the fuel. Water and oxygen are all that is needed to form rust on the interior metal surfaces of the tank.
Each cool down cycle of the machine causes condensation to occur inside the engine and exhaust pipes. It's just like the condensation formed on the outside of your cold drink glass. Where did it come from? The humidity in the air. The engine, exhaust pipes, carburetors, and fuel tank are all vented to the atmosphere. Therefore, moisture has ready access to all those pieces. To rid the bike of this moisture, the machine must be operated long enough to achieve maximum normal temps and then held at that temp. for about 20-30 minutes. This allows the water to be heated, vaporized and ejected from the machine either out the exhaust or out the engine breather tube. The engine breather tube connects to its own filter within the air filter box. This filter can block up with oil/water and inhibits further moisture exiting from the crankcase. During the cold, rainy season here in California, I’ve noticed this filter blocks up in as little as two weeks of daily 30 minute driving intervals with my CB550. If I neglect to clear the breather filter, in another two weeks the dipstick will begin showing white glop, which is water/oil mixed. (It does look like dirty mayonaise!)
Why is water in the oil bad?
Except for synthetic types, oil is made from organic material. When this organic material makes contact with water, amino acids begin to form. The acids react with metal, converting them from metal to, well, something else. The result is the removal of metal from the inside of the engine. Eroded bearings, gears, and such do not a happy engine make.
The stock pipes have weep holes located at the low points of the exhaust system to aid in eliminating accumulated moisture buildup. These should be periodically checked for blockage and cleared if necessary.
I should note that even if you don't run the machine at all, daily heating/cooling cycles will still cause moisture buildup inside the machine. I’ve seen for sale huge bags that entire vehicles are placed into along with bags of dessicant and then sealed for long term storage. I can see that if you drain out all the fuel and oil, this ought to work out pretty well for preservation.
Hope this Helps,
