** SOLVED ** Idiot behind the wheel at fault. Don't forget to subtract the thickness of the straight edge. For reference the following is relating to a 2001 996S I have just fitted new crankshaft bearings (7207X2ETN & 7307X2TB) and went through the steps in the Haynes manual to calculate the required shims for bearing preload. My numbers were: LHS bearing depth (P1): 48.2mm RHS bearing depth (P2): 48.1mm Crank webbing width (A): 87.9mm With a preload of 0.15mm and following the Haynes formula I need LHS shim 4.33mm RHS shim 4.23 For a total shim width of 8.55 According to the Ducati parts list the thickest shim available is 2.55mm So either: a) There is something wrong with my formula or measurements (I did triple check everything) b) The bearings are thinner than expected despite being RHP and appearing identical to OEM c) I can stack multiple shims together Any help would be greatly appreciated.
Not done a twin before, but I'm Ducati singles it's quite normal to use multiple shims so long as the thinest one is sandwiched between two thicker ones if possible. Having said that, 8mm seems to be a huge amount!? The single I'm rebuilding is shimmed for zero end play and has required dropping from 1.2mm to 0.5mm with the new bearings. I can't see why twins would be much different as the shimming is really to make up for machining deficiencies and to apply subtle preload of required. It shouldn't need to make up some 8mm?
You can stack shims, Id be tempted to use two as equal thickness as you can get them rather than lots of thin ones. 8mm does seem quite a lot, make sure you can turn the crank afterwards!.
Ahh, I have just realised where I went wrong. The straight edge width needs to be subtracted from the bearing depth!
