750 engine re-commission

350TSS · 01-07-2022, 01:14 PM

Having spent half an hour with the digital calipers I think I can confirm this engine did not come from a Ducati.

The swinging arm hole on the chain side measures (average of 3 measurements in each axis) 20.7 mm North/South and 22.47 mm East/West (so 1.77 mm oval) on the clutch side the hole is 20.27 mm N/S and 22.00 mm E/W (so 1.73 mm oval).
A Ducati SA spindle is 20 mm diameter and the smallest needle roller bearing with a 20 mm ID is 26 mm OD so these cases have never had a SA bearing.

As it stands the engine is scrap, it cannot be used in a Cagiva without the crankcases being bored and sleeved and it cannot be used in a Ducati without the crankcases being bored to accept needle roller SA bearings. I have no desire to acquire a Cagiva Elephant but I do have lots of Monster spares that could almost make a complete bike.

I have a cunning plan to enable the crankcases to be taken out to accept Ducati SA needle roller bearings involving some 10 mm aluminium plate (250 mm x 80 mm) and a steel bar (45 mm diameter x 70 mm long) both of which are sitting in my scrap bin.

01-07-2022, 01:14 PM	#8
350TSS Too much time on my hands member Join Date: Jan 2013 Location: Shipbourne Bike: M900 Posts: 1,419	Having spent half an hour with the digital calipers I think I can confirm this engine did not come from a Ducati. The swinging arm hole on the chain side measures (average of 3 measurements in each axis) 20.7 mm North/South and 22.47 mm East/West (so 1.77 mm oval) on the clutch side the hole is 20.27 mm N/S and 22.00 mm E/W (so 1.73 mm oval). A Ducati SA spindle is 20 mm diameter and the smallest needle roller bearing with a 20 mm ID is 26 mm OD so these cases have never had a SA bearing. As it stands the engine is scrap, it cannot be used in a Cagiva without the crankcases being bored and sleeved and it cannot be used in a Ducati without the crankcases being bored to accept needle roller SA bearings. I have no desire to acquire a Cagiva Elephant but I do have lots of Monster spares that could almost make a complete bike. I have a cunning plan to enable the crankcases to be taken out to accept Ducati SA needle roller bearings involving some 10 mm aluminium plate (250 mm x 80 mm) and a steel bar (45 mm diameter x 70 mm long) both of which are sitting in my scrap bin.