Fully revised with the latest information on all areas of engine operation, from air and fuel, through carburation, ignition, cylinders, porting, reed and rotary valves, and exhaust systems to cooling. So this system would be ineffective on a two stroke engine if it was used upside down. Tuning and jetting honda, ktm, kawasaki, yamaha, suzuki, husaberg, husqvarna, tm, gas gas. Start by marking motorcycle tuning two stroke motorcycle tuning as want to read. Software for fine tuning and design of two stroke engine. Stroke basically, means the sudden movement of piston which is converted into a rotary motion at crankshaft. Bells four stroke performance tuning book, this book goes into extreme detail regarding performance tuning a two stroke engine. The force created by this expansion is what creates an engine s power. At performance fabrications we offer specialist and dedicated 2stroke servicing and parts, we recommend this as 2strokes can be more unreliable than 4strokes if not properly maintained, with the majority of 2stroke motorcycles now aging it can be important to keep the entire motorcycle fresh to avoid any damage to the engine or other components.
It is my hope that this book will assist the enthusiast involved in motocross, enduro, desert, road or gokart racing to develop and tune his twostroke engine for. In the 2stroke engine with reed valve admission, the identification of petals more adapted to the reed valve and to the engine is essential to maximize the performance starting from the intake phase. The power listed on this guide is from experience not claims. Twostroke engines can work in any orientation, which can be important in something like a chainsaw. Two stroke engines often have a high powertoweight ratio, power being available in a narrow range of rotational speeds called the power. His port time equations dont even include rpm, you input the dime. Two stroke motors are very touchy in the tuning process, if they run too rich, they bog down and quit.
Two stroke high performance engine design and tuning by cesare bossaglia. Tips on how to port a two stroke cylinder, what to donot do and how to do it right. Two stroke high performance engine design and tuning by. If youve ever thought about futzing with the port timing of your scooters one cylinder engine or making your own performance exhaust for your dirtbike or tuning the carb on your go kart, this book is for you. The website does not intend to compeed with any other website dealing with 2stroke tuning, and the information shared is not at all as thorough as what you can get from reading the books. Pages in category performance tuning the following 103 pages are in this category, out of 103 total. Whatever 2 stroke engines styles you want, can be easily bought here. A 2 stroke engine is an engine in which there are 2 phases in a cycle of operation of the engine. I have the book, but its nice to have as a pdf as well and a good reference for those who dont know about it.
Many thanks to everyone that bought the book and i hope you enjoyed it the forward is written by james whitham, and there are contributions from niall mackenzie, terry rymer, jim moodie and jeremy. The illustration below covers the four stages of a four stroke engine. Would recommend to people interested in the inner workings of a two stroke engine. Boosted cars are known to get massive power gains from revised ecu maps, but theres always been a question mark over chipping. Why remapping a naturallyaspirated car is totally worth the money. Twostroke engine repair and maintenance edition 1 by. The fuelair mixture is first drawn into the crankcase by the vacuum that is created during the upward stroke of the piston.
Engine dyno breakin is valuable if you have limited track testing time. The first issue to address is jetting and carburettor tuning. This is a villiers 9e engine but it has a sports conversion 250cc head piston and barrel made by marcelle. The exhaust stroke is the final phase in a four stroke engine. A textbook dealing with the principles of design and construction, with a special chapter on the twostroke engine paperback or softback by kean, francis john and a great selection of related books, art. The stroke is determined by where the shaft is connected to the crank, how far it is off center. Contents chapter 1 introduction 9 chapter 2 the cylinder. Two stroke performance tuning chapter 3 porting and cylinder scavenging today, when we take a look down the cylinder of a twostroke engine, we find its walls literally filled with ports to handle the induction, transfer and exhaust phases of gas flow through the engine.
From a 49cc racing engine, to a gp 125 engine, or a 1500 mercurial triple engine, or a 250 kart engine, racingsm software suits all. Twostroke engines making comeback motorbike writer. In a two stroke engine, the end of the combustion stroke and the beginning of the compression stroke happen simultaneously, with the intake and exhaust or scavenging functions occurring at the same time. Try raising the needle clip one groove away from the pointy end and see if it helps. This is in contrast to a fourstroke engine, which requires four strokes of the piston to complete a power cycle during two crankshaft revolutions. Saabsa saab twostroke engine swapped in motorcycle. Everyday low prices and free delivery on eligible orders. It endeavors to provide the products that you want, offering the best bang for your buck. Twostroke engine repair and maintenance edition 1 by paul. I usually recommend this book along with gordon jennings two stroke tuners handbook, because this book has what the first one doesnt and vice versa. Two stroke cylinder porting tips watch this before you. It is the customers responsible to determine proper engine tuning for their specific track and racing requirements.
Ktm and honda have both registered patents for directinjection twostroke engines. No matter who makes the engine, the first thing i do is lean the idle mixture. This determines the maximum size to enlarge a port. Jennings book talks about port time area and porting the cylinder to have peak efficiency at a certain rpm. A tool to tune your two stroke engine, calculate duration, time areas, etc.
Look at the right side photos below to know what exactly i am trying to say. This 2 stroke engine animation, article and diagrams are courtesty of. The inlet port opens 30 after bdc and closes 79 after tdc. Its worth buying a grahambell book on 2 stroke tuning, still the best.
This may help you understand just how your performance mods and tunings may affect the engine. Two stroke tuners handbook 2 another mistake commonly made, sometimes even by those who have enjoyed some success in modifying two stroke engines, is to believe in a kind of mechanistic magic. Twostroke performance tuning in theory and practice. In other words, the engine will, after tuning, produce more power from the same displacement. Other books to his credit are modern engine tuning, twostroke performance tuning and forced induction performance tuning. Graham bell starts off by saying that he doesnt believe port time area and its all about the duration the ports are open. A twostroke or twocycle engine is a type of internal combustion engine which completes a power cycle with two strokes up and down movements of the piston during only one crankshaft revolution. How to measure your engine port timing and area ratios. When attempting to tune up a motorcycle, consider these main points. What is the differencebetween sbk and motogp lets start with 2 stroke engine.
From the optimization of the engine head, at the studied of the cams, at the sizing of intake and exhaust manifolds, until to the balance of the crankshaft, thanks at our software you could optimize your engine and to develop new. Detailed modifications and improvements are described. Basic 2 stroke tuning changing the power band of your dirt bike engine is simple when you know the basics. Two stroke performance tuning chapter 3 porting and cylinder scavenging today, when we take a look down the cylinder of a two stroke engine, we find its walls literally filled with ports to handle the induction, transfer and exhaust phases of gas flow through the engine. This gives twostroke engines a significant power boost. The most common mistake is to choose the wrong combination of engine components, making the engine run worse than stock. We tailor the tuning to any specific requirements for the individual rider by using port direction. This 2 stroke engine animation is accompanied by an excellent article with several 2 stroke engine diagrams and indepth explanations of the 2 stroke engine cycle. Bigger carburetors, higher compression ratios, altered port timings and expansion. The morbidelli 125 twin road racer is a rotary valve engine. Jun 25, 2010 a 2 stroke engine will 4 stroke when the air fuel ratio is too rich. Bell covers all areas of engine operation, from air and fuel, through carburation, ignition, cylinders, camshafts and valves, exhaust systems and drive trains, to cooling and lubrication. Two stroke performance tuning a disc partially cut away and attached to the end of the crankshaft opens and closes an inlet port in the side of the crankcase.
Graham bell steers you through the various modifications that can be made to coax maximum useable power output and mechanical reliability from your twostroke. This fully revised and updated edition is one of the most comprehensive references available to engine tuners and race engine builders. The combustion stroke is the third phase, where the ignited airfuel mixture expands and pushes the piston downwards. Twostroke engines fire once every revolution, while fourstroke engines fire once every other revolution. Lets journey back to 1973 and read the book that was the two stroke bible of that era. A text book dealing with the principles of design and construction, with a special chapter on the two stroke engine paperback or softback by kean, francis john and a great selection of related books, art and collectibles available now at. Two stroke tuners handbook 2 another mistake commonly made, sometimes even by those who have enjoyed some success in modifying twostroke engines, is to believe in a kind of mechanistic magic. A reference book for the enthusiast engine tuner and race engine builder. Software for optimal setting and design of engines and. Jan 07, 2009 125cc 2stroke tuning guide first things first, you need a good engine, as in no cracks and if you cant fit them yourself good crank bearingsoil seals water pump where applicable. New material on electronic fuel injection and computerized. Other books to his credit are modern engine tuning, two stroke performance tuning and forced induction performance tuning. It covers history, physics, engineering and practicum for the development and refinement of high performance two stroke engines.
Drawing on the authors many years of experience in tuning and modifying highperformance road, rally and race units, every. Those of us who have grown up in the japanese twostroke. With this howto guide, you can win the battle with the temperamental two stroke engine. For sheer power for money and driveability the best setup would comprise of. Destination page number search scope search text search scope search text. The piston crown opens and closes the exhaust and transfer ports. First published in 1981 and regularly reprinted since, this remains one of the most comprehensive works available to the enthusiast engine tuner and race engine builder. Bigger carburetors, higher compression ratios, altered port. To familiarize yourself with two stroke engine tuning, read the two stroke tuners handbook by gordon jennings as well as twostroke performance tuning by a. Why remapping a naturallyaspirated car is totally worth. I think this book is the best book for 2 stroke engine builders and tuners to start out with.
Tuning the 2stroke aircraft engine hi guys, as promised, i am going to go through some things that may help with properly tuning the 2stroke aircraft engine. Bells fourstroke performance tuning book, this book goes into extreme detail regarding performance tuning a twostroke engine. We are not able to replicate your racing environment, therefore we do not offer the tuning service. A 2stroke engine will 4 stroke when the air fuel ratio is too rich. As promised back in march, ktm has unveiled a fuel injected twostroke engine thats expected to give fourstrokes a good run for their money. Drawing on the authors many years of experience in tuning and modifying highperformance road, rally and race units, every aspect of an engines operation is explained and analyzed. This website and app will help you tune your moped or any two stroke engine. Undoubtedly, the virtue which has most contributed to the widespread use and varied application of the twostroke engine is its mechanical simplicity. The illustrated engine features a poppet intake valve.
For manufacter and tuner of four stroke engine, ntproject has developed a series of software to help in the development of the engine and its components. Graham bell second edition this is the moped performance tuning bible as far as im concerned. The two stroke engine employs both the crankcase and the cylinder to achieve all the elements of the otto cycle in only two strokes of the piston. There is no 2stroke displacement limit for our software, for example you can have a 125, 250, 500, 700 singlecylinder and our modules will work flawlessly. Small fourstroke engines are fairly primitive and dont have an oil pump, relying on a splasher or flicker on the connecting rod to throw oil from the sump onto the piston and other moving parts. We cover that, as well as other mods on a four stroke engine. Reviewed in the united states on november 20, 2014. All cylinders are measured as standard and the port dimension are worked out using port time area. Apr 10, 2020 small four stroke engines are fairly primitive and dont have an oil pump, relying on a splasher or flicker on the connecting rod to throw oil from the sump onto the piston and other moving parts. The objective of tuning is to improve the volumetric efficiency of the engine. Workshop services offered by gibbs performance, saltash. A standard fourstroke engine may have problems with oil flow unless it is. Two stroke moped tuning two stroke timing moped tuning. Undoubtedly, the virtue which has most contributed to the widespread use and varied application of the two stroke engine is its mechanical simplicity.
Drawing on the authors many years of experience in tuning and modifying highperformance road, rally and race units, every aspect of an engine s operation is explained and analyzed. The stroke has a major part in how an engine performs. Two stroke tuning maximise the potential power and efficiency of the engine. Why remapping a naturallyaspirated car is totally worth the. Nov 03, 2014 scientists have created a new two stroke engine for use in small cars, notable for its low consumption and low level of pollutant emissions. After really good sales of my autobiography the mechanic who got lucky, i have completely sold out. Those of us who have grown up in the japanese two stroke. I know there are newer books about this subject, but any good ideas they contain surely came from this. A myriad of different aftermarket accessories is available for you to custom tune your bike to better suit your needs. Also i heard you can tune your engine by the spark plugs. With this howto guide, you can win the battle with the temperamental twostroke engine.
Jan 09, 2015 it was a bsa frame with 3cyl 2 stroke watercooled saab engine installed. Ray pye dissatisfied of his motorcycle bsa rocket iii has decided to eliminate its original engine and replace it with the small two stroke engine used by saab on his 96. I usually recommend this book along with gordon jennings two stroke tuners handbook, because this. Twostroke engines were phased out by tough pollution laws and fuel economy targets, but they could be making a comeback with ktm, honda and boutique builders. New twostroke engine, notable for its low consumption and. We specialise in honda 2strokes, covering the cr range of motorcross bikes, the nsr250 street bikes, and hrc grand prix 125, 250, and 500s.