Motorcycle Repair: 71 sportster XL crank/ flywheel timing marks, tdc mark, rear cylinder

Question
I have a 71 sportster XL
I need to know what purpose the marks on the flywheel ( 3 marks = :, ., | ) are their for. I also need to know all procedures taken when checking timing & ignition problems.  

Answer
Your three marks are front cylinder TDC, TDC and rear cylinder TDC. To check timing you need a timing light. Remove the timing plug and insert a clear plug that you can purchace. With the timing light run the bike at idle and look for the TDC mark. Turn the ignition slowly until you see it in the hole.
What kink of ignition problems are you haveing?
mike