1983-1987 Suzuki LT125 Service & Repair Manual

FOREWORD The SUZUKI L T125 was designed to offer superior performance through four stroke power (Twin Dome Combustion Chamber engine), equipped with baloon tires and totally new type design of vehicle. This service manual has been produced primarily for experienced mechanics whose job is to inspect, adjust, repair and service Suzuki Vehicles. Apprentice mechanics and "do it yourself" mechanics will also find this manual to be an extremely useful guide. Model LT125 manufactured to standard specifications is the main subject matter of this manual. However, the L T125 machines distributed in your country might differ in minor respects from the standard-specification L T125 and, if they do, it is because some minor modifications (which are of no consequence in most cases as far as servicing is concerned) had to be made to comply with the statutory requirements of your country. This manual contains up-to-date information at the time of its issue. Later made modifications and changes will be explained to each SUZUKI distributor in respective markets, to whom youare kindly requested to make query about updated infromation, if any.

VIEW OF SUZUKI LT125 ('S3-MODEL) RIGHT SIDE LEFT SIDE

GROUP INDEX GENERAL INFORMATION PERIODIC MAINTENANCE AND SERVICING ENGINE FUEL AND LUBRICATION SYSTEM ELECTRICAL SYSTEM CHASSIS SERVICING INFORMATION APPENDIX ('83-MODEL AND '84-MODELJ LT125E ('84-MODEL) LT125F ('85-MODEL) LT125G ('86-MODEL) LT125H ('87-MODEL)

GENERAL INFORMATION ~--------------CONTENTS------------------~ VIN AND SERIAL NUMBER LOCATIONS······························· ·1- 1 FUEL AND OIL RECOMMENDATIONS····································1- 1 BREAJCIN(;-IN I'ROCi:l>URE·············································. ···1- 1 SI'ECIAL FEATURES············································ ............. ·1- 2 I'RECAUTIONS AND (;ENERAL INSTRUCTIONS··················· ·1- 5 SI'ECIAL MA11E:RIALS·············································· ···········1- Ei SI'ECIFICATlONS······························································ ·1- 8

1-1 GENERAL INFORMATION VIN AND SERIAL NUMBER LOCATIONS The VIN number CD is stamped on the front left frame member as shown in photograph. The engine serial number ® is located on the crank- case. These numbers are required especially for register- ing the machine and ordering spare parts. FUEL AND OIL RECOMMENDATIONS FUEL Use only unleaded or low-lead type gasoline of at least 85 - 95 pump octane (R ; M method) or 89 octane or higher rated by the Research Method. ENGINE OIL Be sure that the engine oil you use comes under API classification of SE or SF and that its viscosity rating is SAE 10W-40. If SAE 10W-40 motor oil is not available, select the oil viscosity according to the following chart: SAE ) 40 i 30 - 20W/SO lOW/SO I ~ 10W/30 5Wi3O 20W lOW - "c -30 20 10 0 10 20 30 40 J Temp. of 22 -4 14 32 50 68 86 104 J BREAKING-IN PROCEDURE During munufacture only the best possible ma- terials are used and all machined parts are finished to a very high standard but it is still necessary to allow the moving parts to "BREAK-IN" before subjecting the engine to maximum stresses. The future performance and reliability of the engine depends on the care and restraint exercised during its early life. The general rules are as follows. 1. Keep to this break-in throttle position. Up to 10 hours Less than Y:z throttle

SPECIAL FEATURES TWIN DOME COMBUSTION CHAMBER FEATURES OF L T125 ENGINE GENERAL INFORMATION 1-2 The Twin Dome Combustion Chamber is a new combustion chamber of the two-valve engine which has been newly developed by SUZUKI Motor Co., Ltd. This combustion chamber is the culmination of SUZUKI's research and development work for the ideal combustion chamber for two-valve engines. Any high-performance engine must meet the following requisites given below: • Good combustion efficiency • Satisfactory intake and charging efficiency It is possible to get a high-performance engine only when these two vital factors are combined ideally. The following is brief explanation on the configuration and features of the newly-developed combustion chamber which has made it possible to satisfy the above-described requisites in a two-valve engine. 1. Configuration of Combustion Chamber Fig. 1 shows a hemispheric type combustion chamber, a two-spherical type combustion chamber and a twin dome type combustion chamber, each having the identical valve arrangement and the same compression ratio. The twin dome configuration means such a shape which would be produced when an egg or a foot- ball is cut crosswise. The following is a comparison chart which indicates features of each type of combustion chambers. Squish areas: C> B > A Combustion chamber volume at cyl inder head side: A > B > C Height of piston head: A> B> C A B Squish area Fig. 1 A: Hemispheric type B: Two-spherical type C: Twin dome type C

1-3 GENERAL INFORMATION 2. Features of SUZUKI Twin Dome Combustion Chamber 1) Swirl The combustion chamber formed by two domes has been so designed that a swirl can be gen- erated readily because of the walls at both side surfaces, resulting in a very quick combustion speed. (See Fig. 2.) 2) Squish The mixture will be injected from the squish areas which are formed at both sides at the final stage of the compression stroke. Such squish effect will further accelerate the combustion speed. 3) Low piston head height As is described in Fig. 1, the twin dome type combustion chamber has the lowest piston head height. Consqeuently, such design feature can produce the following essential advantages. a. The swirl is hardly disturbed. Acceleration of combustion b. The heat-receiving area of the piston can be reduced. Improved durability and prevention of detonation. The foregoing explains how the newly-developed Twin Dome Combustion Chamber has made it possible to produce a remarkable combustion efficiency by combining the swirl and squish effects and low piston head height. Fig. 2 Twin Dome Combustion Chamber Squish area Squish area

GENERAL INFORMATION 1-4 3. Factors Which Enable Excellent Intake and Charging Efficiency Figs. 3 and 4 show the flow state of mixture and the change in cross section in a twin dome type combustion chamber and a hemispheric type combustion chamber, respectively. You will note that the passage area increases sharply at the time of the valve lifting in the case of the hemispheric type combustion chamber. As a result, the flow separation will easily occur. Consequently, the pressure loss increases and the intake mixture volume descreases. On the other hand, in the case of the twin dome type combustion chamber, the intake mixture volume can be increased by controlling the change in passage area at the time of the valve lifting. area Twin Dome Combustion Chamber Conventional Dome Type Fig. 3 area Twin Dome Combustion Chamber Conventional Dome Type Fig.4

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1983-1987 Suzuki LT125 Service & Repair Manual

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