Hi.....The theory that synthetic oils should not be used during break in is the same as the theory that your engine will break in better if you use synthetic oil but add a dinner candle to your four quarts of engine oil. Frankly, I find this theory, um, questionable. Oh, hell, laughable. Corvettes and Porsches come from the factory with Mobil-1 in their engines. Remember, these engineers have designed world-champion engines for F1, Indy, Le Mans 24 hours, etc.
There's a lot of mythology surrounding break-in oil. It's simply not the case that synthetic oils are more "slippery" than conventional oils. Also, break-in of a modern engine is completely different than break-in of an engine made before about 1980. Modern engines, by comparison to something made in the '60s, are pretty much already broken in from the factory due to the fact that today we hold much tighter machining tolerances. The exception, of course, would be the Ural, a motorcycle made on a production line unmodified since about 1935.
I recommend you change your break-in oil at 75 to 100 miles, 100 to 150 kilometers. Your engine does shed a fair amount of metal particles in the first 20-50 miles, and I really can't understand why you would want this stuff floating around your bearings for the first 600 miles, 1000 kilometers.
I put Shell Rotella "synthetic" (87% group III) oil in my DL650 at 75 miles. It burns no oil, gets great gas mileage, and runs great. I recommend you switch to a good synthetic at your first oil change.
