http://www.eurocarparts.com/ecp/p/c...gineoils/5w40-engine-oil/?521776031&0&cc5_248
Use that stuff, got it in my gasser and fzs1000, and car. Works lovely, no problems at all, I've done the research on the specs, it's basically as high as you will get before fuel conserving additives go in.
Seriously, I nerded over this for weeks, my mate with his r6 didn't believe me until I showed him how low a spec bike oils really are. He's got it in his bike now and won't shut up about how nice the clutch is and how "it feels like it revs easier".
If you are going to use atf, try havoline maxlife atf dexron 6, meant for wet clutches and rated for 100,000 miles or 50,000 racing miles to GM spec. I use this in my forks and clutch circuit also, the viscosity at 40c is 28cSt, which is the perfect 7.5w oil, but with all the benefits of an oil actually designed to do something
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I apologise for the hijack, but if you want to save money and do the best for your bike
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I advise against atf in the gearbox if you don't change it often though, the PV drains into the gearbox on our bikes and there are very little acidity regulators in atf, or and gearbox oil. Hence use of a proper engine oil is recommended.