1980-1985 Suzuki GS450 GS450L Service & Repair Manual

INTRODUCTION This detailed, comprehensive manual covers the Suzuki 400-450 series twins from 1977-1987. The expert text gives complete information on maintenance, tune-up, repair and overhaul. Hundreds of photos and drawings guide you through every step. The book includes all you will need to know to keep your Suzuki running right. Throughout this book where differences occur among the models, they are clearly identified. A shop manual is a reference. You want to be able to find information fast. As in all Clymer books, this one is designed with you in mind. All chapters are thumb tabbed. Important items are extensively indexed at the rear of the book. All procedures, tables, photos, etc., in this manual are for the reader who may be working on the bike for the first time or using this manual for the first time. All the most frequently used specifications and capacities are summarized in the Quick Reference Data pages at the front of the book. Keep the book handy in your tool box. It will help you better understand how your bike runs, lower repair costs and generally improve your satisfaction with the bike.

QUICK REFERENCE DATA STATIC TIMING IDLE SPEED SCREW TUNE-UP SPECIFICATIONS Recommended spark plug 1977-1985 1986-on Spark plug gap Breaker point ignition (GS400, GS425) Point gap Dwell angle GS400 GS425 Valve clearance (cold) Ignition timing * GS400, GS425 GS450 Idle speed Carburetor air screw All models manufactured after January 1978 All earlier models * Timing on GS450 models is pre-set. NGK B8ES or ND W24ES NGK B8ES or NO W24ES-U 0.6-0.8 mm (0.024-0.031 in.) 0.3-0.4 mm (0.012-0.016 in,) 180° 190° 0.03-0.08 mm ((0.0012-0.0031 in.) 10° BTDC below 1,500 rpm 40'' BTDC above 3,600 rpm 10° BTDC below 1,650 rpm 40° BTDC above 3,500 rpm 1,100-1,300 rpm Pre-set @ factory (non-adjustable) 1 1/4 turns open No routine timing adjustment is necessary, VII

CAPACITIES Fuel tank GS400. GS425 GS450L GS450E. S GS450ET. ST. LT, TX GS450LZ GS450TZ. TXZ GS450EZ All 1983 models All 1985-on models Engine/transmission oil Without filter change GS400, GS425 GS450 • With filter change GS400, GS425 GS450 At overhaul GS400, GS425 GS450 Fork oil GS400 GS425L GS450N, C GS450LZ GS450EZ GS450TZ GS450TXZ GS450ED Right leg Left leg GS450TXD GS450LD, LF, LG. LH Fork oil level * GS400 GS425LZ GS425E GS450LZ GS450EZ GS450TZ GS450TXZ. TXD GS450ED GS450LD. LF, LG. LH * Measure the oil level from compressed. Liters 14 11 15 14 11 12 14.5 16 13 cc 2100 2600 2400 2900 2700 3000 cc 145 160 m 178 181 143 165 187 155 277 the top of the mm 187 173 187 117 131 m m tm 118.5 fork leg with U.S. gal. 4.0 a? iM 3.2 3.8 4.2 3.4 U.S. qt. ZM 2.7 2J 1.1 2.8 U.S. oz. 4.9 5.4 4J M 8.0 SJ 4.8 5.6 6.3 §J f.4 the fork leg held vertical in. 7.1 6.8 7.1 4.6 5.6 4.9 8.2 7.5 4.7 the spring Imp. gal. 3.1 2.4 3.3 3.1 2.4 2.6 3.2 3.5 2.9 Imp. qt. 1.8 2.3 2.1 2.6 2.4 2.6 Imp. oz. 5.1 5.6 5.1 6.7 6,3 6.4 5.0 5.8 6.6 5.5 9.8 removed and the fork leg completely

CHAPTER ONE GENERAL INFORMATION This book provides service and maintenance procedures for the Suzuki GS400., GS425 and GS450 motorcycles with a manual transmission and chain drive since 1977. Repairing and maintaining your own motorcycle can be an enjoyable and rewarding experience. The following topics provide information on how to use this book as well as general service hints and techniques to make the work as easy and enjoyable as possible. HOW TO USE THIS MANUAL This manual has been specifically written and formatted for the amateur home mechanic. All procedures, tables, photos, etc., in this manual assume that the reader may be working on the bike or using this manual for the first time. This section is included to acquaint the home mechanic with what is in the manual and how to best take advantage of the information. For i:he most frequently used general information and maintenance specifications refer to the Quick Reference Data pages. These colored pages in the front of the book represent a compilation of the most commonly "referred to" facts. The Quick Reference Data pages save you from searching each chapter of the manual every time this information is needed. Readily accessible information can help prevent serious and expensive mechanical errors. To save time on all maintenance tasks, use the Index, The Index in the back of this manual has been carefully prepared and lists all major maintenance tasks by paragraph heading. Whether you want to remove the pistons or simply adjust the drive chain, a quick look in the Index will tell you exactly what page it is on. For a better understanding of manual con- tents refer to the section on Chapter Organi- zation in this chapter. To save yourself time, energy and possible future aggravation, finish reading this entire chapter. If you acquaint yourself with all the special features of this manual it can become a valuable and indispensable tool. This manual can help you achieve a better maintained and more reliable machine. CHAPTER ORGANIZATION This chapter provides general information on how this manual is organized as well as special information and maintenance tips to aid all repair tasks. Read this entire chapter before performing any maintenance procedure. Chapter Two, Troubleshooting, contains many suggestions and tips for finding and fix- ing troubles fast. Troubleshooting procedures

CHAPTER ONE discuss symptoms and logical methods to pinpoint the trouble. Chapter Three, Lubrication, Maintenance and Tune-up, includes all normal periodic and preventive maintenance tasks designed to keep your machine in peak operating condition. Subsequent chapters describe specific systems such as engine, clutch and fuel system. Each chapter provides complete disassembly, repair and reassembly procedures in easy to follow, step-by-step form. If a repair is im- practical for home mechanics, it is so indicat- ed. Usually, such repairs are more economi- cally done by a Suzuki dealer or qualified specialist. NOTES, CAUTIONS AND WARNINGS NOTES, CAUTIONS, and WARNINGS appear throughout this manual and provide specific and important information to the reader. A NOTE usually provides extra or special information to make a step or procedure clearer. Disregarding a NOTE might cause inconvenience but will not cause damage or personal injury. A CAUTION is provided in a procedure wherever mechanical damage of any type may occur. Failure to heed a CAUTION will most certainly result in some form of damage to the machine; however, personal injury is unlikely. WARNINGS are the most serious and are included in a procedure where personal injury may occur if the WARNING is not heeded. Mechanical damage may also occur. PHOTOS, DRAWINGS AND TABLES This manual contains literally hundreds of photos, drawings and tables that are used to support and clarify maintenance procedures. Each photo, drawing and table is referenced at least once within a specific procedure. When using a procedure, take full advantage of all the support data provided to make your job easier and help avoid costly errors. MODEL IDENTIFICATION Suzuki will often make modifications and improvements during a model year. Mid-year changes are usually minor, however, if you are performing repair work you will want to install the latest, most improved parts possible. It is important to keep a record of your engine number and frame number when ordering parts. The applicability of all improved parts is always referenced by the engine number and/ or the frame number. The engine number is stamped on the top of the crankcase (Figure 1). The frame number is stamped on the steering head (Figure 2). When purchasing new parts, if possible, always compare them to the old parts. If the parts are not alike, have the parts or service manager explain the difference to you. GENERAL MAINTENANCE HINTS Most of the service procedures provided in this book can be performed by anyone reasonably handy with tools. It is suggested, however, that you carefully consider your own

GENERAL INFORMATION capabilities before attempting any repair task which involves major disassembly of the engine and transmission. Crankshaft repairs, for example, require the use of a heavy-duty hydraulic press. This type of repair work must be performed by a com- petent machine shop or authorized dealer. Other procedures require precision measure- ments and, unless you have the skills and equipment to make them, it would be better to have a motorcycle shop do the work. Repairs can be made faster and easier if the motorcycle is clean before you begin work. Good soap and pressurized water are usually the best to clean all but the most stubborn dirt or grease. High-pressure, coin-operated car washes do a good job of cleaning, however, the bike must be completely dried and lubricated after washing. High-pressure water and deter- gent can easily enter the wheels, swinging arm and other critical areas and cause corrosion if not treated immediately after cleaning. Clean all oil>' and greasy parts with cleaning solvent. An approved solvent is usually available in bulk form from many automobile service stations a nd parts stores. Never use gasoline as a cleaning agent. It presents an extreme fire hazard. Always work in a well-ventilated area when using cleaning solvent. Keep a fire extinguisher, rated for gasoline and oil fires, handy just in case. If you are not used to working with cleaning solvent wear rubber gloves, if possible, or treat your hands with a good skin lotion immediately after cleaning parts. Solvent will remove the skin oils from your hands and cause painful and irritating "solvent bums" if left untreated. Special tools are required for some service procedures. All special tools necessary are referenced by a Suzuki part number and are available from an authorized dealer. If you are on good terms with the dealer's service de- partment or know a professional motorcycle mechanic, you may be able to borrow what you need. Naturally, much of the labor charge made for repairs by a dealer is for removal and disassembly of other parts to reach the defec- tive area. It is usually possible to perform much of the preliminary work yourself and then take the affected part or assembly to the dealer for repair. Once you decide to tackle a job yourself, read the entire section pertaining to the task. Study the procedures, illustrations, tables and other support data until you have a thorough idea of what is involved in the job. If special tools are required, make arrangements for them before beginning the work. It is very frustrating to get partway into a job and then discover you do not have the necessary parts or tools to complete it. GENERAL MAINTENANCE AND REPAIR HINTS Most of the service procedures covered in this manual are straightforward and can be performed by anyone reasonably handy with tools. Simple wiring checks can be easily made at home; but knowledge of electronics is almost a necessity for performing tests with complicat- ed electronic testing gear. During disassembly of parts keep a few general cautions in mind. Force is rarely needed to get things apart. If parts are a tight fit, like a bearing in a case, there is usually a tool made to separate them. Never use a screw- driver to pry apart parts with machined surfaces such as crankcase halves and valve covers. You will mar the surfaces and end up with leaks. Make diagrams wherever similar-appearing parts are found. For instance, case cover screws are often not the same length. You may think you can remember where everything came from—but mistakes are costly. There is also the possibility that you may be sidetracked and not return to work for days or even weeks—in which interval carefully laid out parts may have become disturbed. Tag all similar internal parts for location and mark all mating parts for position. Record number and thickness of any shims as they are removed. Small parts such as bolts can be identified by placing them in plastic sandwich bags. Seal and label the bags with masking tape.

CHAPTER ONE Wiring should be tagged with masking tape and marked as each wire is removed. Again, do not rely on memory alone. Use a locking compound such as Loctite Lock N' Seal No. 2114 on all bolts and nuts, even if they are secured with lockwashers. This type of Loctite does not harden completely and allows easy removal of the bolt or nut. A screw lost from an engine cover or bearing retainer could easily cause serious and expensive damage before its loss is noticed. When applying Loctite, use a small amount. If too much is used, it can squeeze out and stick to parts not meant to be stuck. When replacing missing or broken bolts, particularly on the engine or frame components, always use Suzuki replacement bolts. They are specially hardened for each applica- tion. The wrong 15-cent bolt could easily cause many dollars worth of serious damage, not to mention rider injury. When installing gaskets in the engine, always use Suzuki replacement gaskets without sealer, unless specifically designated. Suzuki gaskets are designed to swell when in contact with oil. Gasket sealer prevents the gaskets from swelling as intended, resulting in oil leaks. Suzuki gaskets are also cut from material of the precise thickness needed. Disconnect battery ground cable before working near electrical connections and before disconnecting wires. Never run the engine with the battery disconnected; the alternator could be seriously damaged. Protect finished surfaces from physical damage or corrosion. Keep gasoline and brake fluid off painted surfaces. Avoid flames or sparks when working near a charging battery or flammable liquids such as brake fluid or gasoline. No parts, except those assembled with a press fit, require unusual force during assembly. If a part is hard to remove or install, find out why before proceeding. Cover all openings after removing parts to keep dirt, small tools, etc., from falling in. When assembling two parts, start all fas- teners, then tighten evenly. Heavy grease can be used to hold small parts in place if they tend to fall out during assembly. However, keep grease and oil away from electrical components or brake pads and discs. Carburetors are best cleaned by disas- sembling them and soaking the parts in a commercial carburetor cleaner. Never soak gaskets and rubber parts in these cleaners. Never use wire to clean out jets and air pas- sages; they are easily damaged. Use compressed air to blow out carburetor only if float has been removed first. A baby bottle makes a good measuring de- vice for adding oil to forks and transmissions. Get one that is graduated in ounces and cubic centimeters. Take your time and do the job right. Do not forget that a newly rebuilt motorcycle engine must be broken in the same as a new one. Keep rpm within the limits given in your owner's manual when you get back on the road. SAFETY FIRST Professional motorcycle mechanics can work for years and never sustain a serious injury. If you observe a few rules of common sense and safety, you can enjoy many safe hours servicing your own machine. You could hurt yourself or damage the bike if you ignore these rules. 1. Never use gasoline as a cleaning solvent. 2. Never smoke or use a torch in the vicinity of flammable liquids such as cleaning solvent in open containers. 3. Never smoke or use a torch in an area where batteries are being charged. Highly explosive hydrogen gas is formed during the charging process. 4. If welding or brazing is required on the machine, remove the fuel tank to a safe dis- tance, at least 50 feet away. Welding on gas tanks requires special safety procedures and must be performed by someone skilled in the process. 5. Use the proper sized wrenches to avoid damage to nuts and injury to yourself 6. When loosening a tight or stuck nut, be guided by what would happen if the wrench slipped. Protect yourself accordingly. 7. Keep your work area clean and uncluttered.

GENE RAL INFORMATION 8. Wear safety goggles during all operations involv] ng drilling, grinding, or use of a cold chisel. 9. Never use worn tools. 10. Keep a fire extinguisher handy and be sure it is rated for gasoline and electrical fires. EXPENDABLE SUPPLIES Certain expendable supplies are required. These include grease, oil, wiping rags, cleaning solvent, and distilled water. Ask your dealer for the special locking compounds, silicone lubricants, and commercial chain lube pro- ducts which make motorcycle maintenance simpler and easier. Solvent is available at most service stations and distilled water for the battery is available at most supermarkets. TOOLS For proper servicing, you will need an as- sortment of ordinary handtools. As a mini- mum, these include: a. Metric combination wrenches b. Metric sockets c. Plastic mallet d. Small hammer e. Snap ring pliers f Gas pliers g. Phillips screwdrivers h. Slot (common) screwdrivers i. Feeler gauges j. Spark plug gauges k. Spark plug wrench 1. Dial indicator Engine tune-up and troubleshooting procedures require a few more tools, described in the following section. Hydrometer This instrument measures state of charge of the battery, and tells much about battery condition. Such an instrument is available at any auto parts store and through most larger mail order outlets. See Figure 3. Multimeter or VOM This instrument (Figure 4) is invaluable for electrical system troubleshooting and service. A few of its functions may be duplicated by locally fabricated substitutes, but for the serious hobbyist, it is a must. Its uses are described in the applicable sections of this book. Compression Gauge An engine with low compression cannot be properly tuned and will not develop full power. A compression gauge measures engine compression. The one shown in Figure 5 has a flexible stem which enables it to reach cylinders where there is little clearance between the cylinder head and frame. This type of gauge is available at auto accessory stores or by mail order from large catalog order firms.

CHAPTER ONE Impact Driver This tool might have been designed with the motorcyclist in mind. It makes removal of engine cover screws easy, and eliminates damaged screw slots. Good ones are available at larger hardware stores. See Eigure 6. Carburetor Gauge Set A gauge set which can display manifold vacuum for both cylinders simultaneously will greatly simplify carburetor synchronization. Figure 7 shows the Suzuki gauge set. Other aftermarket versions are available. Strobe Timing Light This instrument is necessary for tuning. It permits very accurate ignition timing by flashing a light at the precise instant the cylinder fires. Marks on the ignition advance governor are lined up with the side cover mark while the engine is running. Suitable lights range from inexpensive neon bulb types ($2-3) to powerful xenon strobe lights ($20-40). See Eigure 8. Neon timing lights are difficult to see and must be used in dimly lit areas. Xenon strobe timing lights can be used outside in bright sunlight. Both types work on this motorcycle; use according to the manufacturer's instructions. Tappet Depressor and Tweezer The Suzuki tappet depressor (Eigure 9) is absolutely necessary for performing valve adjustments with the camshafts installed. It is used to hold valve tappets down so the adjustment shims can be removed. If you plan to do your own valve adjustments, order this tool (part No. 09916-64510) from your local dealer.

GENERAL INFORMATION Valve Clearance Feeler Gauge Valve clearances on GS models are critical and have very small tolerance (0.03-0.08 mm). This Suzuki special tool (part No. 09900-20803) is particularly useful for setting valve clearances because it contains gauges ranging from 0.02-1.00 mm with many small sizes n ot usually available in most feeler gauge sets. This tool can be purchased from your local Suzuki dealer. Clutch Hub Holding Tool This handy tool (part No. 09920-51510) is used to hold the clutch hub so the hub nut can be removed (Figure 10). A substitute tool can easily be fabricated by welding steel rods to an old steel clutch plate; however, if you don't have access to a welder it may be cheaper to buy the tool than have one made. The tool is available from your local Suzuki dealer. Compothane Mallet This plastic covered "dead-blow" mallet is virtually indestructable and has become a fa- vorite tool among most professional and amateur motorcycle mechanics. This mallet can be used on most metal surfaces without caus- ing any damage to the surface. The mallet is available in a variety of shapes and weights and can be purchased from most professional tool distributors such as Snap-On and Mac.

1980-1985 Suzuki GS450 GS450L Service & Repair Manual

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