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Discussion Starter #1
Another unusual Italian bike an Aero Caproni.

caprioni 52.jpg

A 75 cc inline single 4 stroke with bevel drive ohc face cam and bevel drive to gearbox chain drive to rear wheel. Engine /transmission diagram attached.
engine transmission diagram.jpg

This machine had completed 2 Moto Giros some years back, not with me. It won awards as the smallest capacity to complete the route. Not running when I brought it, did not complete its 3rd Giro!! but getting it gradually nearer running condition again.
More information on Aero Caproni in general can be found on
Capriolo Home page
 

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What a strange little engine.

I can't quite figure out how the gearbox is supposed to have an influence on how fast you're going (D?). Though it does seem that the oil pump (L) is on the wrong side of the gearbox. :rolleyes:
 

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Discussion Starter #3
Have not stripped the transmission only the head, pictures of the transmission on the website. Assume the gearbox is fairly conventional input to mainshaft then to layshaft and then back to ouput shaft concntric to mainshaft. Loose gears locked by selection (balls it appears) on one shaft, the other shaft has bank of gears locked together.
 

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Nice machinery!

I just hope it's better than the Caproni Ca 313 airoplanes that almost took the whole Swedish Airforce with them when they crashed during the war...
We had 83 of them.

The aircraft were delivered between 1940 and 1941. Between 1940 and 1943, there were 23 fatal accidents at the three air force bases (F 3, F7 and F 11) that operated them. Three more were shot down by Luftwaffe fighters, on 18 and 23 May 1944. 41 crewmen died in these 'flying coffins'. The Ca.313 suffered many engine fires; this situation was not helped by the special fuel that was required. This fuel often corroded the tanks, causing leaks which would result in the fuel spilling onto the hot engines.

B 16 - Caproni Ca 313
 

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Loose gears locked by selection (balls it appears) on one shaft, the other shaft has bank of gears locked together.
As I recall, Lambretta used a similar system in the Li scooters.
That oil pump drive is weird, though, or does the gearbox run constantly and the clutch only acts on the gearbox output?
Whatever, it's an interesting setup,and a pleasant change from the normal in-line 4, water-cooled, 16-valve, UJM. ;)
(Just looked at the Capriolo site.... there's something there about the clutch, but, although the writer's English is vastly better than my Italian, I fear something's been lost in translation!)
 

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Discussion Starter #6
The aircraft connection appealed to me as I spent all my working life in the aerospace industry, also had an ABC (Sopworths post WW1 bike) years ago, again advanced for its era. Someone suggested the engine was derived from an aircraft APU hence the bevel drive
The clutch basket looks like it is connected to the bevel gear in the dismantled engine picture on the website.
 

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Discussion Starter #8
Dragged the bike out this morning, kickstarter turns the engine with clutch engaged or disengaged in or out of gear. Kickstarter will turn back wheel when in gear and clutch engaged but not when disengaged. This is in agreement with the diagram if all the dark gears/shafts are always in drive and the clutch disengages the white gears/shaft.
 

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Good... that means the oil pump's always driven if the engine's running, presumably.
An interesting bike all round: The frame's a bit Nimbus/ early BMW, the rear friction dampers Moto Guzzi.......
Please keep us posted with progress.
 

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Discussion Starter #10 (Edited)
Got it running today!
The oil pump does pump all the time- the gasket I made for the rocker box was not thick enough so the camshaft dumped a load of oil through the small gap over the nice clean engine. At least I know the cam gets plenty of oil, it dribbles onto the cam which throws it around the rocker box like a garden sprayer.
Good bark to the exhaust makes it sound much bigger than 75cc much like a Tiger Cub (200cc if its before your time)
 
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