Before removing the front forks, it is first necessary to remove the
following parts: 
Loosen the clamp screws (1) holding the fork legs to the steering head (3).
Loosen the clamp screws (2) and (26) securing the fork legs to the bottom yoke (4).
Withdraw the fork legs (5) and (6) downwards in order to carry out to all the necessary overhaul operations.

Steering head: front fork
Overhauling the front forksOxygen sensors
Introduction
An on-off type oxygen sensor (in normal operating conditions, the voltage
generated by the sensors switches between a
value close to 1v and a value close to 0v) is mounted on each of the exhaust
manifold of the diavel.
Each oxygen sensor has its own internal heater, which recei ...
Refitting the seat
Note
Apply recommended grease to the hole (a) of latch (6).
Fit the seat (1) as follows: insert the tabs (b) (on the front side) under
the rubber pads (c) of the gloves compartment;
then push the seat rear side until hearing the lock latch click.
...
Checking engine oil level
Check the engine oil level through the sight glass (1) on the
clutch cover. When checking oil level, the motorcycle should
be perfectly upright and the engine cold. The oil level should
be between the two marks next to the sight glass. If level is
low, top up with shell advance ultra 4 engine oi ...