Pretty much any 10W40 oil is fine to use. Read the oil thread at the top of the page for more info.
As far as amount. Get 4 quarts. Put in two and check the dip stick then add a little more and repeat until between the lines on the dip stick. Maybe some one with a 1999 will chime in with the exact amount. Check with bike level and dip stick not screwed in but just resting in hole.
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