Ladetto & Blatto Letter

The following is a translation of a letter sent by Bruno Rossati to Motociclismo d'epoca in 2007. The photographs referred to are currently unavailable. Original Italian pdf.

Giovanni Rossati kindly supplied this information.

Dear Motociclismo d'epoca

It was a pleasant surprise for me to see the article about Messrs. Ladetto and Blatto in the latest issue of Motociclismo d'epoca.

This is especially true given that I worked for them at the time. I'm pleased to take this opportunity to share some thoughts on the matter. I'm also taking advantage of the opportunity I had, here in town, to see the motorcycle built by a craftsman from Avigliana (Vacchiotti), equipped with an OMB pushrod engine, currently undergoing restoration, to take some photos.

I'm sending you some of the engine, thinking it might be useful since others are hard to find. I note that where the OMB name was engraved, it has been replaced with a "Vacchiotti" plate. I'm also sending some photos of what used to be an overhead camshaft.

One is holding it in my hand to show its dimensions. Today, with hindsight, I judge how small the corresponding chain sprocket was, which had to cope with the return of the valves, whose spring load was almost 90 kilograms. The timing chain was a Renold with a 3/8" pitch, the pawls of which, due to the small sprocket, struggled to withstand more than two or three strokes unscathed.

Regarding the published photo of the LADETTO motorcycle.

This hardly refers to the 30/31 model but more likely to the 1932 one. In fact, the engine is from the second series, clearly showing the type with a detached cylinder head with two cast exhausts. The chain-driven Bosch magneto was like the '30 model.

The Best and Lloyd non-returnable lubrication pump and Burman three-speed gearbox. The double wishbone fork is later than the one mounted on the 1930 model. It is therefore either a FIT made by Quadrio or, more likely, a Brampton, the latter being widely used at the time. The brakes were made by Torresini of Turin, on Via Pianezza.

The 1930 model had a head engine cast in a single block with the cylinder, which could be converted into a twin-tube engine by adding a appendage to the single-tube, allowing for modification. It still had a parallelogram fork from Scarafiotti, as on the previous Ladetto and Blatto models.

The gearbox was either the Burman or the Albion, a three-speed manual transmission.

A photo of this model-with a single exhaust pipe and an Albion gearbox-is shown on page 66 of the third volume of "Storia della Motocicletta," published by Bruno Bacchetti, probably a relative of your Adm. Del.

The photo of the loose engine.

This was the last series built, and we jokingly called it "the big head" because of its oversized finning. Pilgrim lubrication pump, again with waste oil. [total loss] Magneto drive was geared instead of chain-driven.

Elastic suspension.

The motorcycle in question - contrary to what is published on page 280, first paragraph, of the fourth volume of the history of the motorcycle, from which the information was likely taken - did not have a swingarm. Its springs were contained in two nearly vertical sliders on either side of the wheel. They were connected to each other only by the wheel hub. Consequently, the motorcycle had the defect of "wagging" because the rigidity of the system depended solely on the size of the pin connecting the two sliders and was not sufficient to prevent flex.

Single overhead camshaft engines from L'Aquila.

I believe the reference is to OMB engines. At this point, an explanation is useful, which, due to lack of publicity, is not generally known. Both the Ladetto motorcycles in question, as well as the OMB motorcycles, were built in the same workshop in Turin, Piazza Santa Giulia 6.

I started working there at the age of 14, after having already worked 11 hours a day for two years in a workshop (it's shocking to say it today) where I had learned-believe me-to work on a lathe and a milling machine thanks to a "boss" who taught us how to set up the machine only once, and then we had to make do, even if it meant "fixing" parts without the risk of him yelling at us. I had a passion for motorcycles, and taking advantage of my family friendship with Mr. Ladetto, I took advantage of it to get hired.

I therefore find myself in a position to know the facts of that time quite well. The owner of the workshop where the Ladettos were built was a certain Mr. BERTOGLIO, hence the name of the workshop "BEST" Bertoglio Silvio Torino. When Mr. Ladetto left for Calabria to dedicate himself to building the OMC, ownership of the workshop passed to Mr. BROGLIA, at the time owner of a pharmacy on Via Vanchiglia.

At the same time, Mr. Blatto, who had moved from France, took over as workshop manager trying his hand at aviation engines with Mr. Concaris, the former owner of Ladetto & Blatto. This marked the beginning of OMB (Officine Meccaniche Broglia) engines and motorcycles. The OMB engines represented a significant advance over the previous Ladetto and Ladetto & Blatto models.

They were built with both pushrod and rocker arm control and single overhead camshafts. They had forced lubrication via a gear pump built into the engine, with pressure regulation and the option of mounting a pressure gauge to monitor the pressure. The connecting rod big end was on needle rollers, and the crankcase was sized to allow for construction with either an external or internal flywheel. The oil was contained in the crankcase itself, thus making it easier for those who purchased the engines separately.

All standard OMB 175cc engines had an external flywheel and two exhaust pipes. The racing bikes were single-pipe exhausts with a bore/stroke ratio of 61 x 59, also with an external flywheel. They were virtually completely reliable and very fast, even the standard pushrod-and-rocker-arm ones. In this regard, I remember that, having sent a standard 175 to Milan to pick up a four-speed Albion gearbox with a foot shift to mount on the racing bike, I completed the 127-kilometer route from one toll booth to the next on the highway in one hour and 23 minutes, averaging almost 92 km. Considering that I had to occasionally recharge the spark plug-certainly not the engine, which didn't need it-I think it was an excellent performance.

The racing model, with overhead valve timing, was built in 175 and 250 displacements. It was entrusted first to the racer Carlo Gobetti. Privately, it was entrusted to Mr. Giacotto and another customer (I don't remember the name). The 250 was assembled especially by Aquila and also entrusted to Gobetti.

The company later passed to an engineer from Turin whose name escapes me at this moment. He intervened in the project, deciding, among other things, to continue construction solely with internal flywheels.

Then came the end of the concessions available to motorcycles up to 175 cc. The entire market for that displacement was shaken by the new rules, and shortly thereafter the new owner decided to close the company. The material was passed to Mr. Guido Premoli of Varese.

Mr. Blatto moved to Milan to work for the BORDONE company, a three-wheeler manufacturer. I worked for the OLLEARO company, responsible for both machining, assembly, and maintenance. Then I worked for Pellini's SIMPLEX company, assembling the 500 cc engine with a block gearbox. Then I did "military service." At the end, I said goodbye to motorcycles and joined FIAT as a draftsman.

Now, approaching 91, I find myself reminiscing about my youth, still riding my motorcycle every day.

It's an incurable disease!

With warmest regards and thanks,

Rossati Bruno

PS: Gobetti won in Bra, in Alessandria (I remember what Tomaselli told me on that occasion - in his own words - "I was on the straight, I heard a turbine behind me, Gobetti came up alongside me, changed gears, and went away"). He had already taken a lap! He raced in Asti, where he retired while leading (during an acceleration, the chain-side wheel lock had failed, resulting in the chain falling off, and he blamed me, saying that I hadn't locked the wheel properly.) In France, in Arcachon, where he won, then in Montlhery, where he retired due to a loose flywheel, then again, winning in Spain, and taking part in the Valentino circuit, in Rome the Littorio circuit, not to mention the hill climbs, with victories at the Sassi Superga and the Torino Pino.

COLLECTORS: Mario Artusio - Bartolomeo Maina - Giovanni Venturino - Fulvio Allasia - Valentino Trivero

If you have a query or information about Ladetto & Blatto motorcycles please contact us