SFC TECH STUFF


SPOT THE DIFFERENCES

In this section you can find side by side pictures to show some of the differences between the various batches of SFCs.

 


Upper picture shows the primairy cover of the 18000 batch, the Electronica; the lower shows the cover on a 16000 batch SFC.

 


Here you can clearly see the different spark plug angle of the 18000 batch SFC (lower pic) and the 16000 batch (upper pic)

Count the fins! 17 fins on the head and 14 fins on the cylinder of the 5000 batch (top pic) and 16 and 13 on the 18000 batch SFC (lower pic). Note the different inlet manifolds, the Amals vs Dell'Ortos, again the spark plug angle.


The early fairings did not only have a different head light, the fairing itself had a different shape also (18000 batch left - 5000 batch right)


Note the many differences in frame design, the footrest plates, theangle of shock absorbers, shape of the seat, side panels etc etc (upper pic = 5000 batch, lower picture 16000 batch.


Clip ons are different, black Verlicchi clip ons, no choke lever, Aprilia light/horn/starter switch on 5000 batch. The levers are only found on the SFC, they are different that on drum brake road versions of the 750. The 16000-18000 batch have the SF2/3 levers, dull chrome Verlicchi clip ons and CEV light/horn/starter switch.

 

 


INSIDE THE ENGINE

 

There was one thing in our book which we would have wanted to include but which we couldn't, the Electronica's special cylinder head.

Here are 2 pictures which reveal some of it's special features.

The above picture clearly shows that the combustion chamber had a radically different shape. The chamber was all aluminium which helped keeping the temperatures lower than in the normal 750 head, which had a cast iron skull.

Thanks to the lower temperatures, the compression could be raised to 10,5 : 1 without the risk of detonation. Also special are a different valve angle, the bronze valve seats, the 7 mm valve stems, the different angle of the spark plug which make these heads very easy to recognise from the outside (we call them 'flat plug heads'). Finally, the cylinder had no spigots.


This picture shows a 16000 batch SFC cylinder head on the left and the Electronica's head on the right. Look closely and you will notice that the rocker spindles are not in the same position.

The bigger valve angle of the Electronica made re-positioning of the rockers necessary in order to be able to use the standard rockers and camshafts!

The 16000 batch cylinder head had the same lay out as the SF with the exception that the valves did have 7 mm stems, the inlets were larger (36 mm instead of 34 on the earlier SFCs) and polished.


These pictures show all SFC pistons.

Left: 9.6 : 1 1971/72 drum brake SFC 5000 - 11000 batch Mondial
Middle: 9.8 : 1 1974 disc brake 16000-17000 batch Mondial
Right: 10.5 : 1 1975/76 disc brake 18000 batch - Electronica Asso

Nothe the very different shape of the Electronica's piston. The deck is much lower because there's no spigot. Put this piston in an SF and you have hardly any compression!