The 1979-1985 Suzuki GS250, GSX250, GS400, GSX400, GS450 repair manual by Haynes covers the following twin-cylinder street bike models:
Suzuki GS250T (GS250), U.K. 1980-1984, U.S. 1980-1982
Suzuki GSX250E (GSX25E), U.K. 1980-1985
Suzuki GSX400E (GSX400), U.K. 1980-1985
Suzuki GSX400T, U.K. 1981-1985
Suzuki GS450E (GS450), U.S. 1979-1983
Suzuki GS450L, U.S. 1980-1985
Suzuki GS450S, U.S. 1979-1981
Suzuki GS450T, U.S. 1980-1982
Suzuki GS450TX, U.S. 1981-1983
Book Excerpt: 1979-1985 Suzuki GS250, GSX250, GS400, GSX400 Repair Manual
FUEL SYSTEM AND LUBRICATION
CARBURETORS: REMOVAL AND REFITTING
To improve access to the carburetor assembly, it is advisable to remove the fuel tank as described in Section 2 of this Chapter.
Commence removal of the carburetor assembly by detaching the throttle cable from the carburetor throttle operating pulley.
To do this, loosen both the locknuts that retain the cable end adjuster to the carburetor mounted retaining clip.
Rotate the throttle twistgrip so that the throttle is fully open and with the flat of a small screwdriver, hold the pulley in the fully open position while releasing the twistgrip to provide enough slack in the cable to allow the nipple to be released from its location in the pulley.
Slide the cable and adjuster sideways to free it from the retaining bracket and tuck the cable out of the way on the frame top tube.
Loosen the clamps between the carburetors and air filter housing and release the housing from the three mounting points located on each inner side panel. Note when removing the retaining screws that one screw each side has electrical leads beneath its head; the position of these screws must be noted for reference when refitting.
Note also that there are bushes located beneath all the screw heads and these must be removed before the housing can be slid rearwards to clear the carburetor mouths. It will also be necessary to ease each side panel outwards so that it clears the housing.
Some difficulty was experienced in freeing the housing from the carburetor mouths and moving it back far enough to clear completely the carburetor assembly, but with the aid of an assistant and a certain amount of patience the job can soon be completed.
FRAME AND FORKS
REAR SUSPENSION UNITS - EXAMINATION, REMOVAL AND REFITTING
Rear suspension units of the hydraulically damped type are fitted to the Suzuki GS and GSX models covered in this Manual. Each unit comprises a hydraulic damper, effective primarily on rebound, and a concentric spring. It is secured to the frame and swinging arm by means of rubber-bushed lugs at each end of the unit.
The units are provided with an adjustment of the spring tension, giving five settings. The settings can be easily altered without removing the units from the machine by using a tommy bar in the hole directly below the springs. Turning clockwise will increase the spring tension and stiffen the rear suspension, turning anti-clockwise will lessen the spring tension and therefore soften the ride.
As a general guide the softest setting is recommended when no pillion passenger is carried. The hardest setting should be used when a heavy load is carried, and during high-speed riding. The intermediate positions may be used as conditions dictate.
There is no means of draining the units or topping up, because the dampers are built as a sealed unit. If the damping fails or if the units start to leak, the complete damper assembly must be renewed.
This applies equally if the damper rod has become bent or its chromed surface badly corroded or damaged. Check also for deterioration of the rubber mounting bushes and of the rubber buffer within the spring.
The piston housing must be free of damage if it is to function correctly.