I'm looking at an '88 750 Paso with low miles and a cracked left case from a broken chain. I know so little about the older Ducatis. What other engines can I get a case from? What is it worth in fully running condition?
Probably the biggest difference in the left side case in the older Pasos to the early '90's and later cases is the clutch slave location. The Pasos are in the clutch basket cover. If they are the same size and shape then maybe all that's needed is a plate to cover the slave cylinder hole. I would assume that the left side cases were pretty much all the same for similar vintage Ducs. If you know a good welder and machinist it could be repaired. It's risky because welding will distort the cover (twist & shrink) and then it would have to be machined flat to seal. They are pretty brittle also.
A low mileage, clean 750 is probably worth high $2's/low $3's. Admittedly they aren't highly sought after. They are unique in styling, being the first fully enclosed fairing Duc, but the 750's (or 906's or 907's) weren't especially fast and the odd size 16" tires have only one manufacturer, Michelin. The weber 2 barrel carb is finicky but a fuel pressure regulator helps. Parts are getting harder to find, but some can be cross referenced to other models.
I'm not sure. An air cooled motor close to that era may fit. The Pasos have a steel trellis frame, but it's made of square stock, not the typical round stock. You would need to check the bolt locations and case width. I would guess a 906 or 907 motor would fit, but they are both water cooled. I don't know if the fairing will accept a radiator and plumbing without modifications.
I would think it would be easier to replace the left side case cover.
If it is only cracked, you may be able to have it safely welded, depending on it's location and whether or not any crucial components are attached in the area of the crack. You also never know when someone will part out a 750 Paso on eBay. I know I've seen a few of them parted out over the years.
I have always thought the Paso bikes were rather interesting. I'd often thought about picking one up, especially since they run in the range of what I typically will get back from my taxes. The 16" wheels are definitely a drawback, but many people have done 17" wheel conversions of theirs. The one to get is the 1992 907 ie version. It already has the 17" wheels and the better suspensions of all of the Pasos from the factory.