On my Harley I ran the HD 20w50 oil through the 1000 mile check up where the dealer put in the HD 20w50. At 5000 miles I started to try different synth oils. The Mobil 1 20w50 the engine made more noise than the HD oil. It ran about the same mileage and engine temps.
Amsoil 20w50 the engine ran cooler made much less noise and gained about 2 mpg.
I tried these oils in the primary and tranny.
During the first few oil changes with synth oils the oil got very dark fairly quickly. After awhile the oil stays cleaner longer.
In reading things about synth oil I found that dino oils no matter how good then to build up sludge in the engine. Synth oils clean this sludge out. Even with only 5000 miles of dino oil in the engine it had built up enough sludge to leave the synth oil dirty for about three oil changes.
I now use the Amsoil 20-50 in the engine, the 10w40 in the primary and the 80w135 gear oil in the tranny.
I change the engine at 5000 miles, the primary and tranny get changed at 10,000 miles.
I use the lighter oil in the primary because I ride in very cool weather. Down into the low 40's and upper 30's. The thinner oils cause less clutch drag at these temps.
The tranny at 10k the oil looks like new. The primary looks dirty because of clutch plate wear.The oil in the primary is used more for cooling the clutch than oiling the chain.
In my 650's I don't run the synth oils because of the frequent oils changes, it is not economically feasible. The extra benefits don't balance with the extra cost. Now if I could separate the oils in the 650 like I can with the Harley I would use a synth oil.
In the XS650 the tranny breaks down the oil by crushing the molecule strands. Engine oil can't withstand that as long as synth oils The clutch just dirties it up to much.
For the XS's I use Valvoline's 20w50 motorcycle oil. It has enough lead in it to help the cam lobes and rockers. Is wet clutch compatible. I can get it at the auto parts stores I shop at. It don't cost to much and I don't feel bad dumping it at 1500 to 2000 mile oil changes.
Leo
........... I find my used oil makes good fire starter in the wood stove. Maybe1/8 cup at most poured on cardboard and kindling, LOT of energy in a quart of oil..............
