Engine Assembly - Polaris 2007 Two Stroke Service Manual

1. Disconnect the coil pack and CDI from the wiring harness.
2. Loosen the carburetor clamps (1) and remove the
carburetors from the mounting boots.
3. Note where the oil lines are routed and remove the oil lines
from the carburetors.
4. Remove the carburetor mounting boots (2) from the
cylinders.
5. Remove both the cylinder head (3) and the exhaust side fan
(4) shrouds from the engine assembly.
• 340 has a intake side shroud
6. After removing the fan shrouds, take note of the vibration
dampener (5) located between the cylinders intake side
(550 only).
7. Remove the recoil cover (6).
8. Remove the recoil cup (7).
9. Hold the flywheel with the holding wrench PN 8700229
and remove the flywheel nut and washer.
10. Using a flywheel puller (PN 2871043), remove the
flywheel (8) from the engine. Do not install the puller bolts
in amy more than 5/16" of an inch/7.9mm into the flywheel
threads or stator damage may result.
11. Remove the flywheel.
12. Remove the blower housing that the stator is mounted too.
NOTE: Make sure to account for the dowels on the
blower housing (550 only).
13. Remove the oil pump (9). Note the o-ring and shim
placement.
14. Remove the cylinder head bolts (10).
15. Remove the cylinder head (11).
16. Remove the head gasket (12). During the removal process
note that the gasket has a EX for exhaust side and UP for
the orientation.
17. Remove the cylinder base nuts (13) and carefully remove
each cylinder (550 only)
18. Remove the reed valve assembly (14) from the crankcase
(550 only).
19. Remove the wrist pin c-clips
20. Using a piston pin puller (PN 2870386) remove the wrist
pins from the pistons.
21. Turn the crankcase over and remove the crankcase bolts
(15).
22. Carefully turn the case back over and separate the case
halves.
23. Remove the crankshaft and crankcase seals (16).
24. Remove the oil pump bushing, spacer, and cross shaft (17)
and inspect for any wear or damage.

Engine Assembly

1. Insert the oil pump cross shaft, spacer and bushing.
Gear
Oil Pump Side
Spacers
o-ring
2. Install a new o-ring on the oil pump.
3. Place the oil pump aside for later installation.
4. Set the crankshaft into the lower case half.
5. Grease the oil pump drive gear area.
NOTE: Make sure that the crankshaft rotates
smoothly and does not bind. Rotate the bearings so
that the anti-rotation pins are resting in their
appropriate galleries.
6. Apply 3-Bond (PN 2871557) sealer to the top half of the
crankcase.
7. Install new crankcase oil seals with spring and lip facing
inward toward the crank bearing.
8. Match up the top half of the crankcase to the lower case and
hold the case halves together and turn it upside down.
ENGINE
Engine side
Spacer
Bushing
5.13
5