The Reliant 850 engine used in the Quasar is mounted as far forwards as possible, but with the standard radiator in the bulkhead in front of it. The engine is installed at an angle to the centreline of the frame, so that it is in line with the offset final drive.

The engine is entirely standard except for shortening of the fan blades to clear the radiator (due to the installation angle) and the fitting of a oil filler pipe in the left side of the sump (as the filler cap in the rocker box is inaccessible).

The standard Reliant dry diaphragm clutch is used, but is converted from cable to hydraulic operation. This entails a shortened clutch lever mounted above the clutch shaft instead of below (as the slave cylinder pushes, whereas the original cable pulled). The slave cylinder is mounted on the right side of the engine block, pushing backwards. The slave cylinder itself is actually the throttle slave cylinder from a Leyland Atlantean bus - these were a design of UK bus with its engine mounted transversely at the extreme rear of the chassis and, now you think about it, would require a length of throttle cable which would have an unacceptable level of friction, hence the hydraulic operation.

The gearbox is also the standard Reliant unit, but converted to a positive-stop foot change. This gearchange mechanism was custom unit for the Quasar and is a piece of engineering which is like the Forth Bridge in its design but is beautifully executed. If you leave me an e-mail querying this, I will produce an illustration, but it would be incomprehensible in words! In case you are wondering: yes, the Reliant's reverse gear is still in the gearbox but, no, you cannot select it.

The propeller shaft passes from the gearbox, through a recess in the side of the fuel tank, under the swing arm pivot to a universal joint on the front of the final drive casing on the left side of the rear wheel. The internals of the final drive are made from Reliant rear axle components, though obviously without the differential.

The fuel tank is located under the seat behind the engine and fuel is drawn out of it by the original Reliant engine-driven fuel pump. In front of the fuel tank, and on the right side of the gearbox is the standard Reliant car battery.

The exhaust is made entirely from stainless steel and runs down the left side of the bike from the standard Reliant manifold and exits alongside the rear wheel. As it passes over the fuel tank next to the prop shaft there is a silencer(muffler)-shaped box, but it is very doubtful if there is anything inside it! Despite the low state of tune of the Reliant engine, the Quasar produces quite a throaty rumble, which would be consistent with it having nearly an open-pipe exhaust.