My 750 Sport with air-cooled cylinders are worn out, the pistons have to large ring grooves etc. The engine has run 88K km.
Have been looking for an engine or parts. Yesterday I got a sweet deal on a 90-ish Monster/SS 750 engine. Oil-heating on the carbs so should be one of the later carb engines. Sweet running engine with 25K on the meter for about €150. So I took it home with me.

I would like to know if it is possible to take the cylinders, pistons and heads from the SS engine and put them om my Sport engine. If it's impossible I will keep the SS engine intact for some other project down the road..

EDIT: I started a somewhat similar thread some time ago and got answers that it could work. But I refrace as I now have an actual engine.

Im surprized that your sport motor is "terminal " at that mileage, but there it is . Why not , instead of disrupting a good low mileage monster motor by swapping bits off it , why not just fit the whole monster motor, specially if it has Mikuni carbs and the sport has the Weber . Probly the only thing that would screw it for you is if the swing arm pivot area on the cases is different ( and some are ) .Im not right up with the play here so I cant say for sure that it can be done but I think it sure is worth a look

The SS has Mikunis and the small diameter swing arm axel. If there is a way to use the Sport swing arm on the SS engine, that would be worth checking out.
Then I would have a spare Sport engine block for my F1 project as well

Well, to answer my own question... have checked, and the SS engine block is 170mm wide, while the Sport is 150mm. So the swing arm is 20mm to narrow. So no obvious solution to this.

McTool, I don't think the hole engine is terminal, I have just checked the cylinders because that is the reason it was put away some years ago by a previous owner.
The front cylinder has a ridge at the top, the ring grooves in the pistons are to wide so the rings is mowing up and down in the grooves.
The heads probably have worn out valve guides but the cams and followers looks OK. Cant feel any gap in the rods, but have to use a indicator clock(or whatever it is called in english) to check if the rods are within tolerance. Since the engine has been stored for many years (in a shop) with the cylinders off, i probably will open up the engine and look/clean it inside to see if there are things I should fix.

Yes, the wider cases puts a dampner on things .
I thought that those engines had plated bores ..... which would make a wear lip a bad sign , and the pistons ( as you describe them ) certainly sound knackered ..... I wonder if that engine has got a bit hot at some stage . Any how your back to your original idea If you were to consider the Mikunis you'd have to give some thought to the air box/ filter set up.
My Paso has just on 67,000 miles and when I got nosey I pulled it to bits and wound up putting in new bearings, seal and rings .........There was nothing wrong with the old ones but once your in there....., in hind sight I wish Id left it alone

you don' t seem to need any anymore ...
http://www.ebay.com/itm/ducati-750-Spor ... 1662624965

Thanks, but that is the air & oil cooled cylinders. I must have the earlier air cooled cylinders.

how are they different?

The air cooled cylinders have large cooling fins while the air & oil cylinders look almost like water cooled cylinders with short stubby cooling fins.

wouldn`t they work just the same? I assume the position of the oil channels is identical.

edit: not even sure why I asked as I know the answer. (I have a bad cold, that`s my excuse) I have an air/oil cooled big bore kit on my Paso.

Probably, but they have the "wrong" look. And I like how my bikes look... Thats why I have four Ducatis and only one Honda...

If I should alter how the engine looks, I would probably check how the cylinders and heads from my 750 Monster/SS spare enige would fit first, since that is a fairly low mile engine. The 750Sport will newer be an "investment" I think, but I would like to have it as authentic as possible.

Hi,

I noticed different jets (donot know the correct name) in the oil channels which had different internal diameter. I think this has to do with the different oilflow requirement for the different setups ( oil cooled VS air cooled)

If it also effects the oil pump, I did not investigate.

Joep, sorry for the silly question but are you sure those "jets" weren't just installed upside down? Just asking because they have a smaller hole on one end. (at least mine do)

It won't make any difference which way up they are. They double up as dowels and they limit the flow to the camshaft and bearings.