changing from synthetic oil back to dino. oil

yeah, you can if you want i guess. i don't know about yamaha, but my bike came with synthetic in it from the factory. always having fresh oil in your bike is more important than what kind is in there...

 

I can't imagine a bike not broken in at 900 miles.

 

You can switch back and forth, but there really isn't a need to. The need to run non synthetic to provide "proper" break in is an old wives tale. Not to mention that modern manufacturing tolerances mean that our motors come from the factory reasonably "worn" in. Now that being said. You do need to be careful what oil you are running as Motorcycles have the unique requirement that the oil runs through the transmission gears, subjecting the oil to tremendous shear forces. Oil obtains it's multi viscosity by utilizing molecules that lengthen when they are heated, which is how oil can become thicker when warm. When these molecules become "ground up" in the transmission it destroys the oils ability to maintain it's viscosity. Which is why it's so important to run "Motorcycle" oil in motorcycles. Also most modern "energy conserving" motor oils contain Molybdenum, which can damage wet clutch plates. Here is an interesting article on oil All about motor oil This article provides an interesting look into the world of lubricants and additive packages, but it's not so technical that the lay person can't digest it. I hope this helps.

 

I use nothing but Mobil 1 in my motorcycle. 1999 Yamaha R1. Today about 40,000 miles (I'm on the third tachometer, may be more miles). The engine runs perfect, didn't need to have the valves shimmed, the transmission shifts like it did on day one and the clutch is original and doesn’t slip. I don't know if this is the kicker but when new it had less than 200 miles before its first track day, I feel that actually helped break it in better (that’s another subject most people don’t understand, proper break-in). I do at least 5 track days a year with that motorcycle and usually cover at least 120 miles on each day so I’d guess about 6,000 miles are race track usage/abusive miles. I’ve been to the drag strip with it at least three times, twice were Yamaha Fun Days at Englishtown, NJ. I did a 6.905 ET at 107 mph on the 1/8 and a 10.2 ET at 136 mph on the 1/4; only one run at lunch time on the 1/4.

I know a scientist who’s job is to analyze oil samples for major trucking firms. What she can tell the customer is the condition of the engine based on the amounts of trace elements found in the oil. She needs to know various details to make the analysis of the data useful. One of the things that she knows is that Mobil 1 is superior to every other oil out there by a decent margin, Castrol Syntec comes up second then the rest start stacking up, the synthetics are at the top of the list. Every part that rubs or moves along another leaves little particles in the oil and its these that show up when testing. The babbit materiel from the main and connecting rod bearings, steel/iron from piston rings, cylinder walls, lifters, cam shafts, rocker arms etc; aluminum from the pistons, and other trace elemenst because she knows what materials (metal alloys) were used in the manufacture of the engine so the results can inform her if a lifter is going bad, a cam is wearing, is it valve quides etc....

From the oil/motorcycle page link, "In 1994, Dr. John Woolum tested the viscosity of several 10w-40 oils in his motorcycle. He found that all of the petroleum oils had lost highly significant amounts of viscosity within 1500 miles. Only Mobil-1 held up in his test."

As for me, I’m a degreed chemist and my job is essentially chemical engineering. Some of these synthetic oils are better than others because of the chemical structure of the oil molecules.

I didn’t get a chance to read the entire web-page oil info but some things you may want to know, especially if you own vintage equipment. There is sulfur in the refined oil too (diesel fuel too Europe specifies a lower level of sulphur in diesel than the U.S. of A for example), especially in the paraffinic refined crude oils (dino oils, which is really a misrepresentation as the primary source of the oil was vegetation not beasts). Ingredients like zinc, phosphorus and other soft metals aid wear resistance to harder metals in motion. This chemistry thing is simple and complex at the same time. Any oil is better than none; but to get to the best requires close attention to the details.

Some other reading you may be interested in. I’d think the ZDDP product would be useful for the Ducati with its Desmodromic valve system.

http://en.wikipedia.org/wiki/ZDDP
http://www.zddplus.com/

P.S. In the old days (like 1940s and 50s) Castor oil was used as make up to the 2-stroke oil/gas mixture because it would bond to the metal surfaces like cylinder walls, piston rings and pistons. Some seemingly crazy things happen inside an engine.

P.P. S. that's an interesting site, thanks for the link.