Sachs mainshaft/sprocket interface

[Gavin Housh]

I've seen several Sachs mainshafts destoyed by the sprocket spinning on the shaft and then becoming welded to the shaft. Once this happens it becomes very difficult to remove the sprocket. Also when installing a new sprocket if the shaft has been damaged you don't get a good bite on the two machined sufaces making it probable that your new sprocket will also be ruined. I've been wondering if it would be possible to key the parts so they can't spin and ruin each other. Has anyone tried this or seen it done? Thanks.

[Richard]

wow,,,you must be getting more hp than I've ever got out of a sachs motor

[joe novak]

I am not going to even check the manual, but I  believe that nut is to be torqued to 50 ft.lbs.  I have never heard of a sprocket spinning on the main shaft.  joe

[gooddirt]

Around one out ten motors in my pile o parts look to have spun. My Super D stuffed case motor spun it . I go 65-70 lbs now.

[Kip Kern]

Clean both surfaces with contact cleaner, install with proper nut and washer, torque to 50 ft pounds.  It works great.  Too much thinking can be a bad thing!:(

[gooddirt]

I would get rid of the above grade scoring and if not to bad do some light lapping.