I bought my 79 about 3 years ago. This bike was built for the German market and later imported to Canada. It came with an owners manual which was printed in German. So I ordered an owners manual (in English) from the dealer. Last year I noticed that the manual was not for my bike (because of some of the information in the manual did not relate to the '79 it related to later bikes). This morning I took some time to see if the specs in the manuals were the same...they are NOT!
Here are some examples of the differences:
Item 79 Later Bikes
Engine Oil Capacity W/O filter 2.0 litre 2.25 litre
Swing Arm Capacity .15 litre .1 litre
Final Drive Capacity .25 litre .35 litre
Exhaust Valve Clearance .15 mm .2 mm
So if you have purchased a new owners manual make sure it is the correct owners manual for your bike.