2005 Ski-Doo Racing Handbook, Page 369Get this manual
SECTION 082005 MX 550 AND 380 FC
ENGINE TYPE 377 552
RING COMPRESSOR PN 420 876 090 420 876 972
Position distance nuts no2 as shown below
NOTE: The ring compressor will not fit on over size pistonsCheck flatness of intake sockets no6Refer to ENGINE DIMENSION MEASUREMENT and look for CHECKING SURFACE FLATNESSAt cylinder no4 andor cylinder head no3 installation, use aligning tool or exhaust manifold itself to ensure sealing of intake manifold and exhaust before tightening cylinder head nutsENGINE TYPE 377 and 552 ALIGNING TOOL PN 420 876 171
A03C1XA
1Exhaust 2Distance nuts