Scooterotica

on some 200cc innocenti cylinders i have seen a small raised pin/boss sideways the inlet
where a single number is stamped on.
0, 1,2,4,

what says this code ?

is it referring to the model (sx/tv/gp) or the cylinder head or the piston ?

I don't know, but how about this for an idea?

Innocenti must have had several moulds for any given model, and perhaps they used these number to identify which mould a certain barrel had come from. In the events of casting errors, the offending mould could be identified, checked and corrected with ease.

Meanwhile, someone will be along in a minute with a proper explanation......

The barrel in my 230 cast is 3 but don't know what it means. I know the barrel is an italian late SX200 or early GP200

Two of my GP 200's had the number "3" cast onto the inlet port of the barrel....both late GP's.....

As I recall the raised numbers denoted the various alterations to barrels that Innocenti fitted. Porting heights etc. I also believe that there were six or seven on TV200 barrels because of ring breakages on exhaust ports. But someone with access to the technical data service sheets issued to agents in the 60's would be able to clarify this point.

Soulpunk wrote:on some 200cc innocenti cylinders i have seen a small raised pin/boss sideways the inlet
where a single number is stamped on.
0, 1,2,4,

what says this code ?

is it referring to the model (sx/tv/gp) or the cylinder head or the piston ?

.......within general machining guides especially in the sixties, when engine cylinders were first bored by the manufacturer, a number was stamp on each bore (car engine) and when it moved further along the assembly line the corresponding piston with that grade number was fitted to it`s respective bore....so therefore the bore was only measured once when bored then stamped with the correct fit number.....this was so that the tolerance for each was the same for all four ( you cannot have passengers!)....On the Lambretta two-stroke of course the process is repeated but not quite as important because of it`s single cylinder nature but nevertheless the clearances or tolerance between the bore and piston have to be correct....Don`t forget we are on commercial production lines where the cylinders are just bored quickly one after the other and not in a special one-off workshop where all the care is given for a good tolerance (honing included)....on standard piston`s there will be also a grade number 0 to 4 as well as the familiar arrow.......this process is only for first production as the cylinder is bored down the road somewhere and the piston is made up the road somewhere else.....when re-boring takes place at your special workshop, you have to have the piston first....it`s then measured and the bore is then match as near as possible to the stated tolerance............