There is nothing wrong at all =D
900 is more than enough for tickover.
yes it does have an alternator.
Your alternator only comes on after a certain charging voltage is reached (maybe around 1-1200 RPM) hence your lights get brighter, this is perfectly normal.
When at tickover the lights are dim, when you rev it the lights get brighter. The tickover seems very low about 900rpm, could that be the problem, does the XJ900 have an alternator if so could this be at fault?
