The 1980-1982 Yamaha RD250, RD350 Liquid-Cooled Twins repair manual by Haynes, covers the following motorcycle models:

• Yamaha RD250-LC (liquid-cooled), May 1980-1982
• Yamaha RD350-LC (liquid-cooled), June 1980-1982

Book Excerpt: 1980-1982 Yamaha RD250, RD350 Twins Repair Manual ROUTINE MAINTENANCE

CLEANING THE AIR FILTER ELEMENT The air filter element on the Yamaha LC models is of the oiled foam type and is housed in a molded plastic casing beneath the fuel tank. To gain access to the element the seat and tank must be removed as follows. Unlock the seat and lift it clear of the frame. Turn the fuel tap to the "Off" position and pull of the fuel pipes. Remove the single rubber mounted bolt at the rear of the tank. Raise the rear of the tank slightly and then ease the tank backwards to disengage it from its mounting rubbers at the steering head. Remove the air filter cover by unscrewing its three retaining screws. The flat foam element can now be lifted away. Wash the element in clean gas to remove the old oil and any dust which has been trapped. When it is clean, wrap it in some clean rags and gently squeeze out the remaining gasoline. The element should now be left for a while to allow any residual gasoline to evaporate. Soak the cleaned element in engine oil and then squeeze out any excess to leave the foam damp but not dripping. Refit the element, ensuring that the cover seals properly. The tank and seat can now be refitted. Note that a damaged element must be renewed immediately. Apart from the risk of damage from ingested dust, the holed filter will allow a much weaker mixture and may lead to overheating or seizure. It follows that the machine must never be used without the filter in position.

FRAME AND FORKS

FRONT FORKS: DISMANTLING AND REASSEMBLY

1. Having removed the forks from the yokes as described in Section 2 withdraw the fork springs and invert each leg over a drain tray until the damping oil has emptied. It is assumed that the fork top plugs were removed as described prior to their removal from the fork yokes. If the plugs are still in position they can be removed by clamping the stanchion in a vice fitted with soft jaws. Take care not to crush or score the stanchion. Depress the plug with a cross-point screwdriver and pry out the wire circlip which retains it. Release the pressure on the plug, allowing it to be displaced by the fork spring. The fork leg can now be removed and drained as described above.
2. Once the oil has been drained, slacken the bolt which passes up through the bottom of the lower leg and into the damper rod. It is quite likely that the damper rod will tend to rotate in the lower leg and thus impede the removal of the bolt. If this problem arises, clamp the assembly in a vice using soft jaws to hold the lower leg by the caliper mounting lugs. Obtain a length of wooden dowel about 1/2 in. in diameter and form a taper on one end.
3. Pass the dowel down the stanchion, having first withdrawn the fork spring. Push the dowel hard against the head of the damper rod to lock it in position whilst an assistant slackens the retaining bolt. If the dowel proves difficult to hold a self-grip wrench or similar can be used to obtain sufficient leverage and pressure. Once the retaining bolt has been removed slide off the dust seal and withdraw the stanchion assembly from the lower leg.
4. Invert the stanchion to release the damper rod and rebound spring, placing these components to one side to await examination. Unless new oil seals have been fitted recently they should be renewed as a matter of course to prevent failure at a later date. Lever out the wire retaining clip using a small screwdriver.

Subject: 1980, 1981, 1982 Yamaha RD250, RD350 Liquid-Cooled Twin service, maintenance, repair. ISBN-10: 085696803X | ISBN-13: 9780856968037 | Haynes 803