Replacing Gearcase Bearings

The four cam gear needle roller bearings in the crankcase are a press fit and can be removed and installed without disassembling crankcase by using Tool, Part No. 97270-60 as shown in Fig. 3D-18A. When installing cam gear needle roller bearings, always press on printed side of bearings, being extremely careful not to tip or misalign bearing in the case during the installing operation.

If inspection warrants replacement of either the cam gear or pinion gear bronze bushings in the gearcase cover, it first is necessary to separate the right and left crankcase sides and remove the flywheel assembly. See "Crankcase," Section 3E.

To remove the six blind bushings from the gearcase cover and one blind bushing (idler gear) from the crankcase, use special Puller, Part No. 96760-36. Puller body provides four special pull-tap sizes to accommodate bushings. Screw puller-tap into bushing. Slip puller sleeve (use the stepped sleeve to clear bushing boss) over tap and assemble puller nut with handle as shown in Fig. 3D-14. Turn puller nut clockwise to pull bushing from gearcase cover.

Before pressing in new bushings, note location of original dowel pin holes for reference when drilling new holes. When drilling new holes, be sure to locate holes 1/8 in. or more from original dowel pin holes.

Use a smooth surfaced disc or plate slightly larger than flange when pressing bushing into position. Be sure bushing flanges are seated tight against gear-case cover and/or crankcase idler gear bushing.

After new bushings have been pressed in, they must be dowel pinned with cover bushing pins to prevent them from turning. Drill a hole with a number 31 drill, 9/32 in. deep, through bushing flange and into aluminum so when dowel pin (28, Fig. 3D-11) is driven in and bottomed, its end will be slightly below face of bushing flange. Peen bushing around dowel pin hole to prevent pin from coming out.

After all bronze bushings have been pressed in and dowel pinned, all but the idler gear bushings must be line-reamed.

Parts order bushings are furnished nearly to size so there is little stock to be removed when reaming bushing. When removing reamer, keep turning it to the right as it is being pulled out.

To ream idler gear bushings, use special Reamer, Part No. 94806-57. Carefully align and turn reamer into bushing until it bottoms.

To line-ream the circuit breaker shaft bushing in the gearcase cover, insert special Reamer Part No. 94803-37, through crankcase needle roller bearing. Reamer will be a close fit in needle roller bearing, providing alignment for reaming the gearcase cover bushing.

See Fig. 3D-15. Slip cover bushing reamer over end of smaller reamer and insert pin through reamers and install pin retainer. Install gearcase cover, at same time starting cover bushing reamer in cover bushing. Turn reamer into crankcase and gearcase cover bushings until it bottoms in gearcase cover. Remove gearcase cover and then remove cover bushing reamer from smaller reamer.

To line-ream the front exhaust, front intake and rear exhaust cam gear shaft bushings in the gearcase cover, assemble the cover to crankcase side. With cover bushing reamer removed, insert special Reamer, Part No. 94803-37, through needle roller bearing, into cover bushing and turn until it bottoms in case cover.

To line-ream the pinion gear shaft bushing, install gearcase cover. Insert steel pilot bushing into crankcase bearing race to guide reamer. Insert special Reamer, Part No. 94812-37A, through pilot bushing into pinion gear shaft bushing, and turn reamer until it bottoms in gearcase cover. Remove gearcase cover.

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