Rotax 125 MAX evo - Cylinder Components

BRP-Rotax
REPAIR MANUAL
Chapter: Chapter 4
CYLINDER COMPONENTS
TOPICS IN THIS CHAPTER
System description .................................................................................................................................2
Cylinder removal .....................................................................................................................................3
Removal of the spark plug......................................................................................................................4
Removal of the cylinder head cover ........................................................................................................4
Removal of the thermostat .....................................................................................................................5
Removal of the combustion chamber insert .............................................................................................6
Removal of the exhaust socket ...............................................................................................................7
Removal of the intake socket and reed valve ...........................................................................................8
Removal of the exhaust valve (125 MAX only) .........................................................................................8
Removal of the piston ..........................................................................................................................10
Cylinder components inspection........................................................................................................... 11
Inspection of cylinder components ........................................................................................................ 11
Inspection of piston and piston ring .......................................................................................................12
Inspection of the Piston diameter ..........................................................................................................13
Inspection of the Piston and cylinder sizing............................................................................................14
Inspection of the Piston pin, circlip ........................................................................................................15
Inspection of the spark plug..................................................................................................................15
Inspection of the cylinder head cover ....................................................................................................17
Inspection of the combustion chamber insert .........................................................................................17
Inspection of the exhaust socket ...........................................................................................................18
Inspection of the carburetor flange and reed valve .................................................................................19
Inspection of the exhaust valve (125 MAX only) .....................................................................................20
Cylinder components installation..........................................................................................................21
Installation of exhaust valve (125 MAX only)..........................................................................................21
Installation of exhaust valve, gasket, valve rod housing ..........................................................................22
Installation of the exhaust valve piston ..................................................................................................22
Installation of piston .............................................................................................................................24
Installation of the cylinder.....................................................................................................................25
Installation of the exhaust socket ..........................................................................................................26
Installation of the carburetor flange and reed valve.................................................................................27
Installation of combustion chamber insert ..............................................................................................29
Installation of cylinder head cover .........................................................................................................29
Inspection and adjustment of squish gap ...............................................................................................31
Installation of spark plug ......................................................................................................................33
Contents This chapter describes the disassembly and assembly of the cylinder components of the
ROTAX® 125 MAX evo (incl. Junior-, Mini-, Micro MAX evo) engine. The description is
divided into sections.
Effectivity: 125 MAX evo, Junior MAX
evo, Mini MAX evo, Micro MAX evo
Edition - February 01 2018 /Rev. 0
Chapter 4
Page 1