If your using a chemically derived synthetic such as AMSOIL, a 40 weight is plenty for reducing engine wear. When I see 6ppm of aluminum wear, and 2ppm iron, after a race weekend,, that says it all. I recommend AMSOIL 10w-40 for all water cooled motorcycles. I only reason I change my oil every race weekend, is due to Fuel Dilution. With every racebike i've owned, 4-7% fuel dilution after 300 race minutes. We are always full throttle, and fuel bypasses into the oil very quickly. The 40weight (SAE 40 = 12.5 to 16.3 cST) drops into the 30 weight category with that much fuel. 30weight (SAE 9.3-12.5cST) I'm run AMSOIL 10w30 MC too, but not a good idea with fuel dilution, as it will become a 20weight soon enough.
Using a 50 weight can actually increase operating temps, due to extra viscosity drag.
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Be informed about chemically derived Synthetics.(PAO) Reduced engine wear with extended drain intervals is possible. Oil Analysis Proves everything.
Last edited by Irnieracing; 10-30-2012 at 07:00 PM.
There are a lot of excellent full synthetic oils. Rotella T6 is a 5W40 full synthetic oil available in Walmart for $21 a gallon and it carries the JAMO MA (which means it works for motorcycle wet clutches) rating. I use it in everything. Piaggio uses 5W40 full synthetic oil in all it's bikes and scooters including the Aprilia Tuono V4 for the entire N. American market...Canada, the US, Mexico, so 5W40 would work for sure also. If a dealer recommends a certain brand of oil, it is likely because that is what they make the most money on. People who have no vested interest and know oil and motorcycles usually will tell you there are many acceptable oils. I would use any of them with the proper specs. as written in your owner's manual.
Super Streetbike magazine recently did dyno testing for a 0w-40 Motorex oil and a 15w-40 Chevron Delo oil, and they got an extra 1.6 peak horsepower from the more expensive oil made in Switzerland.
I think they were dumbasses for not comparing Rotella T 15w-40 and the less than zero weight oil below, instead of two 40 weight oils at normal operating temperature, that are seldom used by motorcyclists. Note which magazine has an ad on the page below:
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"He had never counted on anything except surprise and unpredictability and danger" from Lee Child's Bad Luck and Trouble novel (2007)---------------
"There's always the chance I'll screw up. That's what keeps it from getting boring."
from Dean Koontz's The Eyes of Darkness novel (1981)
Super Streetbike magazine recently did dyno testing for a 0w-40 Motorex oil and a 15w-40 Chevron Delo oil, and they got an extra 1.6 peak horsepower from the more expensive oil made in Switzerland.
I think they were dumbasses for not comparing Rotella T 15w-40 and the less than zero weight oil below, instead of two 40 weight oils at normal operating temperature, that are seldom used by motorcyclists. Note which magazine has an ad on the page below:
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