HRC spec 30:1, but as Les has said, they will indeed run with considerably less oil. Only use a fully synthetic 2T oil, especially if you are going to try and run less than the recommended 30:1, and try and stick to one brand. Motul 710 is probably the easiest to get in the USA.
Bear in mind that changing the fuel:oil ratio will also effect the jetting, and what works for one person/motor won't necessarily work for another! Hence why I won't personally quote any numbers! Also be aware that the fuel used by Les here in the UK could differ quite significantly in both octane rating and ethanol content, so I would say start at 30:1, and work down if you really feel it necessary.
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Andy.
NSR-WORLD.COM
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