DJB - there is no part number, it just says Motorcycle Service Manual Supplement at the bottom and has a picture of the 1989 KDX200 (Road Legal) on the front. Unfortunately, I didn't buy it - was just given a free copy.
As for oil/fuel ratio, the oil cable needs to be adjusted so that at throttle stop (idle), oil pump lines up with one mark and full throttle lines up with the other.
This is pretty obvious when you take the cover off the oil pump.
The oil pump alos has a check valve which needs to be operational.
Oil Pump performance test is conducted as follows.
Fill the tank with premix.
Pull out the oil feed pipe from the carb manifold and plug hole with a bolt.
Start bike and keep it at 2000rpm.
With oil pump cover off, open oil pump lever fully.
Allow oil to pump into measuring container for 3 mins at 2000rpm.
Output should be between 3.6 and 4.2mL (sorry don't know the conversion by memory).