Forgot the Magdyno Strap?

By Hans Muller
WDM20 58764
May 2007

You have finished cleaning the crankcase halves, bearings are ok, and you have put the halves together with all the necessary precautions. Now you lift the motor in the frame, enter and tighten all the bolts and studs, take the freshly restored Magdyno to put it in place and then: HORROR! You forgot to put in the straps that hold the magdyno in place.

These straps are fixed with two studs: crankcase stud (top, rear) 31-212 and crankcase stud (rear) 24-949. And if you forget to slide on those straps before assembling the two crankcase halves, you have a problem, because it is virtually impossible to get those studs out again once the crankcase halves are together. The protruding thread is too short to screw on a second nut, so you can either fix the nut on the stud with a punch and several hammer blows, or separate both crank case halves again.

A better solution? Replace both studs with bolts; take long enough M8 bolts, cut off the threaded part and put 5/16" Whitworth thread on them (of course, you could weld the nuts on the studs, but I think that's a botch). Now you can replace those Magdyno straps without separating the case halves.