Frame: 1968 CRS

The 1968 CRS was a production dirt track racer. Production figures on this frame and year are somewhere around 100. The frame is dimensionally similar to the street frames, but differs in a few areas. The main backbone downtube of the frame is of circular cross-section rather than elliptical. There is a reinforcement channel welded under this downtube. The motor is hung from the frame via aluminum plates. The other main difference is the large, reinforced steering stop that is designed to stop 35mm forks. My project will not be using 35mm forks.

My frame required eight hours of grinding to remove extra bracing that a previous owner had thought necessary. Otherwise, the frame was in very nice condition.

Engine: TV-350 (sort of)

I built the engine for this bike by combining two US production units. The goal was to build an engine effectively similar to a European TV-350. The 1969-72 US engines were 350's, with a four-speed and rounded head. The round-head was a departure from most Aermacchi engines and is generally considered inferior for visual and cooling reasons. The 1973-74 US engines were 350's also, with a five-speed and knuckle-head. These later engines also came with different cases to support an electric start, wider crankshaft to support an alternator and left-side shift.

From the earlier unit (1969-72) I used the cases, crankshaft, generator and sidecovers. From the later unit (1973-74) I used the transmission, clutch, sidegears, camshaft, cylinder and head. The two obstacles to this project were a special mainshaft spacer for the transmission conversion and a right-side five-speed shifter pawl carrier (European or race part) for the shifter conversion.

The details of the final engine are: 350cc, knuckle-head, dry clutch, five-speed, and right-side shift.

Fuel Tank: 1961-62 CRTT

This 1961-62 CRTT, production road-race, fuel tank is a very rare item. Production numbers on the early CRTT are probably about 100. Most of the steel tanks, like this one, got pitched when the aluminum tanks came out. The shape of this tank is closely related to the 1967-68 H model in the US and the Ala Verde in Europe. The differences are that the large plastic fuel cap is fully recessed (top of hump at rear of tank), the large cutouts in the bottom for carb/remote float, the dual petcocks and the front tank mount design.

When I received this tank it was in very poor condition. I had to cut new threaded inserts for the fuel cap and one of the petcocks. Both of these were silver-soldered in place. The rear of the tank had a large palm-sized dent that had to be professionally pulled. I was able to note the original color and striping before I fully removed the existing paint. The tank will be painted back to original red/white.

Seat: Ala Verde

The seat for my project is a European model, designed for the Ala Verde.

Brakes: 1970-74 SS

The brake diameter is the same for all the production Sprints, but the 1970-74 SS had a double leading-shoe front brake. I will be using this front brake. Also, the rear hubs are designed differently between the 250's and 350's. I will be using the 350 style rear hub to carry the sprocket that matches my 350 engine.

Wheels: Akront/Borrani

The rims have not been purchased yet. I aim to use shouldered aluminum Aktronts or Borranis. Both the front and rear will be WM2 x 18, 36 hole.

Suspensions: Front - Ala Verde (sort of), Rear - CRS, ERS

For the upper triple clamp bracket of my project, I am using one from a 1961-62 C. This part is visually closest to the smooth upper triple clamp brackets that were on the Ala Verdes and race models (models with clipon handlebars). I am in the process of shaving and filling the C model bracket to be visually identical to the smooth models. For the lower triple clamp stem and bracket, I will be using a smooth one as well. These were available on the 1961-66 C and 1962-68 H models. Later years and models had a headlight mount built into the lower triple clamp bracket.

For the fork tubes and sliders for my project, I am using ones from 1962-68 H and 1967-70 SS, excluding 1963-64 H. All of these models used the same lower slider. This is my main concern, as I wish to run an H model style low fender. The reason that the 1963-64 H model sliders are excluded is because they used a high fender with no fender mount locations on the sliders. It is interesting to note that the 1967-70 SS models used the same sliders, but used a 19" wheel and 19" fender. 1971-74 SS, SX models used taller lower sliders than I wish to use. The fork tubes and springs for my project can really come from more models than I've mentioned. There were only two fork tube lengths used among all the models; C models (1961-66) used the short tube, all other models (1962-74 H, SS, SX) used the long tube.

The rear shocks for my project are CRS, ERS competition units. These differ from the standard units in there is more spring on the shock and the spring is adjustable (three positions). It is interesting to note that the CRS, ERS shocks differed from the CRTT shocks in the following ways: the CRS, ERS shocks used painted springs and had an upper spring cover (same part as C model), the CRTT used chrome springs and had no upper spring cover.

Fenders: 1964-66 H

The fenders for my project are stock fitment on 1964-66 H model. They are designed for 18" wheels. The rear fender is a full length fender ( extending fairly far back in the rear ), much like the C model, but with shallower side valences.