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Old 11-20-2007, 10:16 PM   #10
Island Hopper
gunnerbuck's Avatar
Joined: Nov 2005
Location: N.V.I, B.C.
Oddometer: 4,351
#1 If the bearing just seized and all the needle rollers are in place only fine particulate may of gone into the motor. If thats the case you may get away with just doing the repair along with with a few oil flushes. Pull the drain plugs and see what the magnets say...

#2 I would say to just spring for the new part rather than trying to rebuild the old cam.

#3 I don't know of any aftermarket follower bearings for the 640. The OEMs are not that costly and I think are your only option. They are a little tricky to replace as the bearings consist of loose needles and a pastic containment sleeve that slides out when the shaft is pushed thru. As Bill mentioned you will have to press the old shafts out {I used a ball joint removal press to do mine} as the shaft ends have been flared with a ringstamp. The new shafts can be pushed in by hand and the ends can be flared by carefully dimpling the shaft ends 6-8 times per end with a small centerpunch around the outside edges.

#4 Use the crankshaft locking bolt to lock the shaft you can then loosen and remove the sprocket retaining bolt. Pry the bearing circlip up out of its groove. You then can tilt the cap bearing end of the camshaft up and slide the shaft out of the sprocket. Once clear of the sprocket the shaft, bearing and circlip can be lifted out together and a dowel can be put in the sprocket to hold it in place....
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