Enduro Prototype
OSSA made only a single prototype enduro bike. The design was quite innovative, as you will see in the following text and photos. It's a pity this project was not developed further.
In researching the topic, I was surprised to learn the bike was exhibited at the EICMA show in 2011, only 2 years after the trials prototype was introduced. That must have been a heady time for OSSA, full of promise.
The photo below is from that 2011 EICMA show in Milan. The OSSA personnel from left to right are: Joan Gurt, Jordi Cuxart, Alexandre Laplaza, Joan Roma, unidentified female.
Contemporary news stories stated that twin injectors (one in the crankcase and one directly into the cylinder) were employed. There was also the mention of an electronic exhaust valve. Both of those features can be seen in the following photos.
Josep “Xiu” Serra's website has a brief description of his involvement with the project highlighting KERS (Kinetic Energy Recovery System). In 2011, KERS was a hot topic with the Formula 1 engineering community. It provides a way to make use of kinetic energy (during deceleration) that would otherwise be wasted in the brakes. The electrical implementation of KERS uses a motor/generator, battery and control electronics. This system also provided the electric-start function. There was no provision for kick-starting.
The following photos show the current condition of the prototype, which resides in Barcelona and is being offered for sale at 25,000 euros. Unfortunately, the seller says it isn't in rideable condition, and never was. It was made only for the show. The final photo provides contact information.
Two Injectors
The adjacent photo shows fuel hoses for two separate fuel injectors. One appears to be in the crankcase in roughly the same position used on the trials bikes.
A second injector is fitted directly onto the cylinder. Both injectors were under control of the Kokusan Denki ECU.
Interestingly, with the trials bikes, K-Scan reports values for injector #1 and ignition #1. I had assumed this was to allow the software to also report on a twin-cylinder engine, but it would now seem to offer more flexibility than that.
Exhaust Valve
This view clearly shows the head and cylinder exhibiting a large projection not present in the trials models.
Generally speaking, electronic two-stroke exhaust valves use either a blade or a spool to alter the exhaust timing and port area. Control may be either open-loop (no position feedback) or closed-loop.
Closed-loop actuation is often accomplished via a servomotor using a potentiometer for feedback.
KERS
A storage battery for the KERS can be seen below the water pump at the bottom of the photo. The wire size gives a hint as to the current involved. It would be better to utilize something more than the typical 12V electrical system in this application. So, maybe 48V would be reasonable? But I am guessing.
You can also see what looks like the standard 34-position ECU connector (but no ECU) in this photo. There appears to be more wires in the harness than the trials model required. At a minimum, additional wires to operate the exhaust valve and second injector would be needed.
Reed Box
In this greatly-cropped photo, we can just make out the reed box. It is huge when compared with the trials models. Likewise, the external shape of the cylinder casting for the transfer ports indicates to me this was a propose-built enduro cylinder, not a warmed-over trials design.
Documented Features
Front suspension: Öhlins upside-down, 48mm stanchions
Rear suspension: Öhlins with rocker (no dog bones), offset from chassis center-line
Front brake: 260mm disc, Brembo caliper
Rear brake: 220mm disc, Brembo caliper
Exhaust: snail-type expansion chamber from welded cone segments
Weight: 97 kg (~214 pounds)
