Rotax 277, 277 Rotax engine manual assembly.

277 Rotax - Rotax  277  Engine Manual

To avoid damage to the crankshaft resp. to the bearing, the puller assy. for ball bearing 6305.has to be used (see removing of bearing, ill. no. 6).

Warm crankcase, magneto side, up to approx. 800C ( 180 degrees F) Press oil seal 230 425 with mounting jig till to the stop. 
Press crankcase ring 960 765 in with mounting jig. 
Fill groove between oil seal lips with high temperature bearing grease and mount crankshaft. 
Place crankcase gasket.

Mount oil seal 850 050 and aluminum crankcase ring 827 820 in crankcase, p.t.o. side. 
Mount crankcase half.

Tool: Rubber hammer (plastic hammer).

Tighten hex. screws of crankcase in a cross sequence (starting from the middle) with 18 -24 Nm (160-210 in.lbs) 

Tools: Torque wrench insert 13 for torque wrench

Close crankcase cavity with a clean cloth.

Insert piston pin needle cages in bore of connecting rod

Warm up piston to 40 - 50 degrees c (arrow on top of piston must show towards exhaust).

Insert guide pin for piston pin through the piston hole and connecting rod bore. Take care not to damage the needle bearing.

Coat piston pin with oil, place it on guide pin and insert it into piston hole. All punch impact must be absorbed by your hand to avoid bending of the rod (arrow on piston crown must show towards exhaust).

The circlips must engage in the grooves of the piston. Use new circlips. Insert circlip, in such a way that open ends are not over the rectangular slot of the piston, as otherwise the circlip would have to be turned around when disassembling later on. 

Circlips must sit tightly in the groove.

Tool: Screwdriver shaped as shown on ill. no. 2

Mount cylinder base gasket. 

Attention: This gasket is not symmetrical. Place it in the correct position. Take care of the transfer recesses in the crankcase.

Lubricate piston and bring piston rings in correct position (securing pin between ends of piston ring).

Press piston rings into the grooves and mount oiled cylinder over the piston.

Mount cylinder head gasket and cylinder head. Tighten hex. nuts M8 at 18 - 24 Nn (160 - 210 in. lbs) in a cross sequence,

Tools:  Torque wrench insert 13 nun for torque wrench.

Mount armature plate so that marks on armature plate and crankcase correspond.

Fix armature plate with allen head screws and insert cable grommet.

Tool: Hex. socket screw key 4 mm

Mount Woodruff key on crankshaft taper.

Fix piston to top dead center by inserting a crankshaft fixation bolt through the impulse nipple.

277 Rotax - Rotax  277  Engine Manual

Clean crankshaft taper and taper in inagneto housing with degreasing agent (e.g. trichloroethylene).

Coat crankshaft taper with LOCTITE 242 blue (899 786)

Mount magneto housing with assembled fan on the crank shaft.

Attention:

Before mounting magneto housing with fan on the crank- shaft, take care that the ignition unit and especially the magnets are clean and free of foreign material.

Secure thread of hex. nut M18 x 1.5 with LOCTITE 242 blue,

899 786, and tighten hex. nut with torque 90 Nm (800 in. lbs). 

Tools: Torque wrench insert 27 mm for torque wrench

IGNITION ADJUSTMENT

Ignition timing 190 ( 2.03 - 2.53 mm  or  0.08 - 0.10 in before top dead center) 

To adjust the contact breaker gap., the piston has to be placed to top dead center. Adjust contact breaker gap to 0.4 mm (0.016 in.). To do so, loosen the fixation screws of the contact breaker set and push the contacts with a screwdriver until the gap is 0.4 mm (0.016 in.). This distance has to be checked with a feeler gauge.

Then turn crankshaft until the contact breaker cam makes the contact lever lift (check with buzzer or check lamp); connection to shorting cable and to mass.

Now the mark on crankcase has to correspond with the mark @ on the fan. If the marks don't correspond, the contact breaker gap can vary between 0.35 and 0.45 MM (o.o14 -0.018 in.) to achieve correspondence.

When correct timing is achieved, check pole shoe break- away gap.' The gap must be within 8 to 17 mm or 0.3 to 0.67 in. (see illustration) when the mark on the flywheel corresponds with the mark on fan housing.

If the break-away gap is out of tolerance, the flywheel may have turned on the crankshaft. Remove flywheel and inspect taper and key. Repair if necessary.

Mount ignition coil 
Tools: Socket wrench 8 nun screwdriver

Screw on starting pulley 
Tool: Socket wrench 10 mm

Mount fan cowl and cylinder cowl. 
Tool: Socket wrench 10 and 13 mm

Mount carburetor socket with gasket 
Tool: hex. socket screw key 6 mm 19 sp,

Screw on exhaust socket with gaskets and air guide. 
Tool: hex. socket screw key 6 mm.

Remove crankshaft fixation bolt.

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