Note: The following response was taken from the Honda Nighthawk Listserver on YahooGroups. It was a reply to someone desiring more information on purchasing a Nighthawk 650 and what kind of repair and maintenance issues to expect. You'll find that if that 650 has been well
cared for, there are no specific problems to worry about. The
charging systems are not necessarily problematic if you understand
their limitations. They WILL NOT CHARGE at idle; the battery
actually discharges at a rate of about 10 amps at idle. "Break
Even" is at around 2000 RPM, and above 2500 you're charging. And
that's the spec, so that's just the way it is. Most of us use
battery tenders to keep the batteries at peak charge when we're not
riding. Other than that, the only known issue that might be worth reporting
is that the cam chain tensioner spring tends to lose some of its
tension, allowing some cam chain noise after a while. I don't know
anyone who's actually had one come apart, but I guess it can get
pretty irritating. My 650's got around 23,000 on it with no issues
(and it was really abused before I got it, for the first 11k). Take care, good luck and keep us posted!
Ben
'83 650SC
Grand Blanc, MI