Model F Racer

Innocenti produced several open-frame factory racers, but none of them were as outrageous as this example from Jeff Wilkes.

Within months of Lambretta production starting, Innocenti began building factory racers. Entering them into endurance races was seen as a great way to promote the Lambretta brand by proving their reliability and strong build quality. This continued for some time with the open-framed C and D being the most commonly modified models. Following them down the production lines were the E and F, but by the time of their introduction, the factory had stopped the development of race machines as the brand was so successful and they were no longer required to generate publicity. It was a shame, as no doubt they could have continued to build some stunning examples, but it is doubtful if the E and F would have been included even if race development had continued.

The E and F were budget models, specifically designed to challenge Lambretta’s rivals on cost. To make them affordable, they used cheaper materials, and the build quality suffered accordingly. The E proved to be unreliable in certain areas and as its reputation began to harm the brand, it was replaced with an improved version, the Model F. It was a short-lived scheme that was quickly deleted from the Lambretta catalogue and so ended Innocenti’s venture down this route. However, its inline engine made it a unique design and it would have been interesting if they had developed a race version of it. Alas, it wasn’t to be, but that doesn’t prevent someone with a fertile mind imagining what could have been.

Tired

Jeff Wilkes is no stranger to the world of scooter customisation and enjoys an engineering challenge. An avid Lambretta enthusiast for the last 40-odd years, he has owned and ridden most models Innocenti ever produced. He was looking to do something different for his latest project, a task that isn’t easy these days, so he opted for a Model F. With the tyres having rotted off the rims, you can imagine the state it was in, but that didn’t matter in the slightest. This was the ideal state for it to be in because the plans Jeff had in mind made it the perfect base from which to start. The idea was to turn it into a racer, which, considering the fragile nature of the engine, wasn’t going to be an easy task.

The project wasn’t just about the engine but for the machine in general, developing its chassis and cosmetic look. Plenty of inspiration can be taken from the examples of racers that exist as to how far the concept could be taken, but as you can see, this concept has supersized anything that went before. This is a racing machine that is crammed full of ideas that only a creative mind can achieve. Like any project, the first step was to strip it down and see what there was to work with. Surprisingly, most of it was in good shape, which meant Jeff could quickly begin to weave his magic.

All geared up

The centrepiece of any race machine is the engine, especially on an open-frame model. Once stripped, the work could commence, and the cylinder had the ports cleaned up by friend John Gilbert. There was no point going over the top trying to create too much power because the rest of the engine couldn’t cope with it. Even with minimal work, certain parts needed upgrading as there are several weak points, and this started with the crank. Its unique design allows the web to be unbolted on one side, meaning removing the con rod is simple. The con rod has a brass bush for the small end, so Jeff replaced it with one from a TV175 Series 2. This is an exact fit but has a needle roller bearing instead of the brass bush, giving better reliability. Another weak point is the ignition, which had reliability problems during its production run. Here, help came from Tino Sacchi, who already produces an ignition for open-frame models. However, because the crank taper was slightly different on the F, Tino modified it to fit. This meant it would have electronic ignition but as a side benefit, Tino’s system also facilitated 12v lighting.

The carburettor was also changed, swapping the tiny Dell’Orto MU14C1 for another Dell’Orto, but this time, the much better UB20S. This side floating racing carburettor has a much more accurate atomiser, and there is just enough space to fit it on to the fixed manifold on the cylinder. A thumb-operated choke was also designed and fitted, making its operation much easier. Finally for the top end, the exhaust, is a Silentium straight-through pipe and has a rather a strange name because it has no baffles. Silent it isn’t and though the engine doesn’t rev high, thanks to this pipe, it’s deafening.

Working down the drive train, next to receive Jeff’s attention was the drive shaft, which was very thin on the F, so Jeff replaced it with the much stronger D version. Now came the really tricky part: the gearbox, which, because of being inline, is not the easiest to understand. It has a fixed cluster connected to the end of the crank; while opposing it are the gear cogs on another shaft connected to the drive, remember this is a three-speed gearbox. This was another weak link in the design, so Jeff had the cogs that go on the shaft remade, ensuring they were 0.5mm wider in diameter. It may not sound much, but the original cogs were worn due to the weak design, and the new ones would substantially improve their operating lifespan. None of these modifications to the drive train are visible but they all help to improve reliability in the weak areas of the design and are a testament to Jeff’s engineering skills.

Tanking it

Another problematic area of the F was the front forks and suspension. Jeff did away with the original 8in rims, upgrading them to 10 inches. This was achieved by modifying the hub plate of a PM tuning disc brake and bolting it directly to the brake drum. This, in turn, allowed a 10in wheel rim to be fitted, a process that was repeated at the back hub and gave just enough clearance for the mudguards. To improve the suspension at the front, the fork springs were upgraded, and a mount for dampers on either side was fitted. These have a similar angle to those on a Series 3 Lambretta and use that model’s original pencil-type hydraulic dampers.

The fuel tank for the model F was adequate for the 14mm carburettor, but not for the 20mm that’s now fitted. So, another fuel tank has been added to give an extended range. This torpedo-shaped design was crafted by Jeff and mounted on to the end of the frame tube, to all intents looking like it was intended to be there. It has its own tap, which feeds on to the fuel line of the original tank so they can be operated independently of each other. When first looking at the machine side-on, you’ll notice a sister tank clamped below it. This is, in fact, a storage tank for two-stroke oil and has a small dispensing tap which pours oil into a cup, neatly housed underneath the spare wheel at the back.

The list is endless

As for the other touches and enhancements, we will list them quickly, as there are so many that it would take half this magazine to mention them all. On the engine, to aid air cooling (remember there is no fan on the flywheel), there is an extravagant air scoop to trap air and help cooling around the barrel. A grease gun, spark plug spanner, oil cup, oil can holder and fire extinguisher are neatly mounted along the frame. At the rear, there’s a bespoke spare wheel with a holder and locking nut conversion on the rear hub nut. Cosmetically, the twin front headlights, front deflection plate and centre frame spacers are just a few of the finishing touches.

The attention to detail is incredible, and it’s possible to spend a lot of time admiring the workmanship in every aspect of the machine’s makeup. What’s more impressive is that it’s all Jeff’s own work and that includes the painting of its bright and vivid deep red colour. However, there is one part of the work he didn’t carry out, which is the polishing, but he kept it in the family because this was expertly done by his wife, Jane. Together, working as a team to get a precise finish, they achieved results that speak for themselves.

Here, Jeff has created something unique and used his imagination to get the desired result. The model F was a short-lived concept by Innocenti and an often-overlooked model. It was never turned by the factory into a racing version like the C and D, which is a shame. However, what you see before you is what could have been achieved, and dare I say, even eclipses what Innocenti could have produced.

Words: Stuart Owen

Article originally appeared in Scootering Magazine February 2025 issue. To subscribe and grab some Meguiars cleaning freebies visit https://classicmagazines.co.uk/scootering?offer=SCOME2026