Crankcase Fretting

[mcomeaux53]

I've seen some issue's with crankcase fretting on certain Rotax engine serial numbers starting with #5645 in the serial number and production dates in approx 2005 year models. Was this due to improper torque values on the case? I researched the Rotax site and was unable to find resolve or actual cause. Can anyone chime in with information pertaining to this issue? Considering a purchase and would like to get info if possible.

[Wheels]

I was told at Rotax repair school in Canada that the fretting issue was caused by one or maybe it was more of the through bolts that held the case halves together. These bolts allowed the case halves to "work" and the fretting issue became a leak. The mechanic would sometimes tighten the case halves and induce a binding of the journals on the crankshaft itself. At least thats the way I remember it. If you call Rotech Research in Vernon BC and ask for Mike or Rob, they will straighten us all out.

I have 700 hours on one and no fretting.

[mcomeaux53]

Thanks for the info..