Make the rear wheel turn until you find the position where chain is tightest. Set the vehicle on the side stand. Push down the chain at the point of measurement and release. Measure the distance between the "aperture" upper profile and pin centre.
The read distance must be: 9 to 11 mm.

Important
If the drive chain is too tight or too slack, adjust it so that tension reading will fall within specified range.
To adjust the tension remove the rear splash guard (sect. 7 - 13, Removal of the swingarm).
Slacken off the two clamp screws (1) that secure the rear wheel hub to the swingarm.
Fit the hook spanner code 88713.1038 Inserting its tooth in the eccentric hub (2).
Rotate the eccentric hub (2) to obtain the correct chain tension.
Turn counter clockwise to tighten the chain; clockwise to loosen (from chain side).
Important
An incorrectly tensioned chain will lead to accelerated wear of the transmission components.
If the screws (1) are removed, lubricate with specified grease underhead and thread, then tighten the screws (1) to the torque of 35 nm +/- 5% (sect. 3 - 3, Frame torque settings) proceeding with sequence 1-2-1.

Warning
The correct tightening of the fixing screws of the eccentric hub is essential for the safety of the rider and the passenger (sect. 3 - 3, Frame torque settings).
Refit the rear splash guard (sect. 7 - 13, Refitting the swingarm).
Adjusting the steering head bearings
Checking brake pad wear and changing brake padsRemoval of the swingarm
Before removing the parts in question, you must first carry out the following
operations:
Remove the rear wheel eccentric hub as described in chapter "removal of the
rear wheel eccentric hub and rear wheel
shaft" of this section.
Loosen screws (7) and remove the hose grommets (13), (15) ...
Check the idle and the co amount with warm engine
Start the engine;
Switch on the dds and check that it does not signal any error (otherwise
consult the relevant paragraph of this manual
to reset the error and proceed with the idle check);
Enter the "self diagnosis" menu by selecting the diavel model in the
available vehicle version. ...
Disassembly of the oil pump
Hold the oil pump (1) in a vice taking care not to damage the drive gear
(12).
Warning
Make sure that vice jaws are faced with soft material.
Remove the plug (14) and extract the spring (16) and by-pass valve (17).
Check the condition of the above components.
Remove the circlip (6) ...