User manual APRILIA PEGASO 650

[. . . ] ­ The information and illustrations contained in this manual are updated to the moment of its publication. ­ This publication is meant for professional mechanics, therefore many notions have been intentionally omitted, as they were regarded as superfluous. Reserves the right to modify its models at any time, without prejudice to the main characteristics here described. All rights as to electronic storage, reproduction and total or partial adaptation, with any means, are reserved for all Countries. [. . . ] Make sure that the carburettors are correctly inserted in the two manifolds of the cylinder. From this point onwards, proceed with the reinstallation of the carburettors starting from NOTE (Y), see 4. 3 (REMOVING THE CARBURETTORS) and following the reverse order with respect to the removal. Once the carburettors have been reinstalled, it may be necessary to adjust the accelerator cable, see 2. The following operations refer to the disassembly of the left carburettor, but are obviously valid also for the right carburettor. If both carburettors are disassembled, be careful not to mix up the components (some of them look alike, but they aren't). Position the carburettors with the chambers facing upwards on a clean and clear surface. Upon reassembly make sure that the gasket (4) is not damaged and that it is correctly positioned in the hollow seat on the chamber. The disassembly and the successive reassembly of the components must be carried out with the greatest care, since even the slightest damage to any of them may negatively affect the carburetion and therefore the engine efficiency. Firmly press the float unit (5) with two fingers (see figure) and withdraw it from its seat by lifting it. Upon reassembly make sure that the needle valve correctly fits in its seat (6). By forcing slightly on the two fulcrum points, separate the float (7) from the support (8) and take the needle valve (9), being careful not to damage the clip (10). Unscrew and remove the air screw (13), taking the spring (14), the washer (15) and the O-ring (16). Unscrew and remove the two screws (17-18) and take the washers. Take the membrane (21) as indicated in the figure and lift it, thus withdrawing the whole unit. Upon reassembly make sure that the membrane (21) is sound and that its outer edge is correctly positioned on the hollow seat of the carburettor body. Overturn the membrane/gate valve unit (21-22) and take the conical needle (23), the washer (24) and the ring (25). Upon reassembly make sure that the conical needle (23) correctly fits in the seat hole. Proceeding as indicated in the figure, remove the membrane (21) from the gate valve (22). 6 CHECKING THE COMPONENTS Make sure that the components listed below are sound, with no damaged point, and that no clogging is present: 7 CHECKING THE NEEDLE VALVE Should any foreign matter enter the carburettor and penetrate between the needle seating and the needle, the fuel will continue to flow until it overflows. The same problem may arise if the needle is worn beyond the tolerance limit. If the rubber part of the needle shows evident wear (see figure), change the needle. [. . . ] rEMEDY Check rotor , stator , and unit , change defective component. Use spark plugs with prescribed thermal value. 2) Countershaft not positioned in correspondence with signs. Noise seem to come from engine shaft or from countershaft. [. . . ]