Vortex ROK DVS J, Owner'S Manual

Page: 28 / 45

MAINTENANCE
DVS-Junior
25
4.6.7 PISTON CHECK AND MAINTENEANCE
10mm Tube Wrench
Torque Wrench
To avoid engine damage, a Vortex qualified mechanic
must perform inspection and honing.
Remove exhaust.
Remove spark plug. Remove the six head nuts and
relative washers.
Remove cylinder head by pulling it up carefully.
Once cylinder is separate from crankcase, hold the connecting
rod with the other hand and pull the cylinder out totally by
pulling it up carefully.
Every time cylinder is removed we recommend changing
cylinder gasket. (3)
Remove the circlips from
the piston pin. Push the pin
out of the piston. (4)
Before
assembling a new
piston check
dimensional sizes. Correct
cylinder/piston clearance is 0.12mm.
ASSEMBLING
Oil and insert the roller cage in the connecting rod.
Install the new piston in the connecting rod by placing the
arrow stamped in the head of the piston facing the exhaust
port.
Insert now the piston pin and secure it with the circlips.
Attention, wrong circlips assembling may cause serious
damage.
Insert the piston ring in the piston carefully. Check both ends of the piston ring when totally closed
have a gap of 0,30/0,35 mm.
Now you are ready to assemble cylinder and cylinder head as per 4.6.6
Engine needs a brake-in session when a new piston has been placed.