Why remapping a naturallyaspirated car is totally worth. A standard fourstroke engine may have problems with oil flow unless it is. Twostroke engine repair and maintenance edition 1 by. Twostroke engines making comeback motorbike writer. So this system would be ineffective on a two stroke engine if it was used upside down. 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. Two stroke engines often have a high powertoweight ratio, power being available in a narrow range of rotational speeds called the power. Bigger carburetors, higher compression ratios, altered port. 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. It endeavors to provide the products that you want, offering the best bang for your buck. The illustration below covers the four stages of a four stroke engine. New twostroke engine, notable for its low consumption and. 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. Those of us who have grown up in the japanese twostroke.
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. 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. The stroke is determined by where the shaft is connected to the crank, how far it is off center. 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. 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 starts off by saying that he doesnt believe port time area and its all about the duration the ports are open. 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. This is in contrast to a fourstroke engine, which requires four strokes of the piston to complete a power cycle during two crankshaft revolutions. It covers history, physics, engineering and practicum for the development and refinement of high performance two stroke engines. 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. 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 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. Why remapping a naturallyaspirated car is totally worth the. This fully revised and updated edition is one of the most comprehensive references available to engine tuners and race engine builders.
Everyday low prices and free delivery on eligible orders. An excellent academic book on the theory behind performance tuning for 2stroke motorcycles. His port time equations dont even include rpm, you input the dime. Undoubtedly, the virtue which has most contributed to the widespread use and varied application of the two stroke engine is its mechanical simplicity. Tips on how to port a two stroke cylinder, what to donot do and how to do it right. When attempting to tune up a motorcycle, consider these main points.
Jun 25, 2010 a 2 stroke engine will 4 stroke when the air fuel ratio is too rich. Twostroke engine repair and maintenance edition 1 by paul. 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. Software for optimal setting and design of engines and. The force created by this expansion is what creates an engine s power. 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.
New material on electronic fuel injection and computerized. How to measure your engine port timing and area ratios. 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. Saabsa saab twostroke engine swapped in motorcycle. As promised back in march, ktm has unveiled a fuel injected twostroke engine thats expected to give fourstrokes a good run for their money. Destination page number search scope search text search scope search text. Graham bell steers you through the various modifications that can be made to coax maximum useable power output and mechanical reliability from your twostroke. 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. 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. Software for fine tuning and design of two stroke engine. Workshop services offered by gibbs performance, saltash. Look at the right side photos below to know what exactly i am trying to say. The morbidelli 125 twin road racer is a rotary valve engine. 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.
Two stroke high performance engine design and tuning by. The most common mistake is to choose the wrong combination of engine components, making the engine run worse than stock. Twostroke engines fire once every revolution, while fourstroke engines fire once every other revolution. Stroke basically, means the sudden movement of piston which is converted into a rotary motion at crankshaft. Start by marking motorcycle tuning two stroke motorcycle tuning as want to read. 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. The exhaust stroke is the final phase in a four stroke engine.
Would recommend to people interested in the inner workings of a two stroke engine. A 2 stroke engine is an engine in which there are 2 phases in a cycle of operation of the engine. For sheer power for money and driveability the best setup would comprise of. Pages in category performance tuning the following 103 pages are in this category, out of 103 total. Try raising the needle clip one groove away from the pointy end and see if it helps. The piston crown opens and closes the exhaust and transfer ports.
This is a villiers 9e engine but it has a sports conversion 250cc head piston and barrel made by marcelle. 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. A 2stroke engine will 4 stroke when the air fuel ratio is too rich. Lets journey back to 1973 and read the book that was the two stroke bible of that era. 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.
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. A reference book for the enthusiast engine tuner and race engine builder. What is the differencebetween sbk and motogp lets start with 2 stroke engine. 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. 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. Boosted cars are known to get massive power gains from revised ecu maps, but theres always been a question mark over chipping. 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. Basic 2 stroke tuning changing the power band of your dirt bike engine is simple when you know the basics. 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. After really good sales of my autobiography the mechanic who got lucky, i have completely sold out.
I usually recommend this book along with gordon jennings two stroke tuners handbook, because this. Two stroke cylinder porting tips watch this before you. 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. Undoubtedly, the virtue which has most contributed to the widespread use and varied application of the twostroke engine is its mechanical simplicity. Jennings book talks about port time area and porting the cylinder to have peak efficiency at a certain rpm. The illustrated engine features a poppet intake valve. The combustion stroke is the third phase, where the ignited airfuel mixture expands and pushes the piston downwards. There are some very good two stroke tuning guides from. I know there are newer books about this subject, but any good ideas they contain surely came from this. Bells fourstroke performance tuning book, this book goes into extreme detail regarding performance tuning a twostroke engine. Twostroke engines can work in any orientation, which can be important in something like a chainsaw. The fuelair mixture is first drawn into the crankcase by the vacuum that is created during the upward stroke of the piston. Tuning and jetting honda, ktm, kawasaki, yamaha, suzuki, husaberg, husqvarna, tm, gas gas.
Graham bell is an acknowledged expert on engine tuning, with many years experience in this field. Drawing on the authors many years of experience in tuning and modifying highperformance road, rally and race units, every. 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. It is the customers responsible to determine proper engine tuning for their specific track and racing requirements. No matter who makes the engine, the first thing i do is lean the idle mixture.
But still if you have any problem or if you do not understand then feel to ask me. A tool to tune your two stroke engine, calculate duration, time areas, etc. Contents chapter 1 introduction 9 chapter 2 the cylinder. 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 stroke has a major part in how an engine performs. 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. Whatever 2 stroke engines styles you want, can be easily bought here. Why remapping a naturallyaspirated car is totally worth the money.
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. The first issue to address is jetting and carburettor tuning. Two stroke motors are very touchy in the tuning process, if they run too rich, they bog down and quit. We cover that, as well as other mods on a four stroke engine. 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. 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. Two stroke high performance engine design and tuning by cesare bossaglia. The power listed on this guide is from experience not claims. Bigger carburetors, higher compression ratios, altered port timings and expansion. We are not able to replicate your racing environment, therefore we do not offer the tuning service. Graham bell second edition this is the moped performance tuning bible as far as im concerned. Twostroke performance tuning in theory and practice. The objective of tuning is to improve the volumetric efficiency of the engine. The engine is quite small and light and uses only two.
Other books to his credit are modern engine tuning, two stroke performance tuning and forced induction performance tuning. A myriad of different aftermarket accessories is available for you to custom tune your bike to better suit your needs. Bells four stroke performance tuning book, this book goes into extreme detail regarding performance tuning a two stroke engine. The inlet port opens 30 after bdc and closes 79 after tdc. Jan 09, 2015 it was a bsa frame with 3cyl 2 stroke watercooled saab engine installed. With this howto guide, you can win the battle with the temperamental two stroke engine. Ktm and honda have both registered patents for directinjection twostroke engines. This determines the maximum size to enlarge a port. All cylinders are measured as standard and the port dimension are worked out using port time area. Shorter or longer conrods, along with fabricated spacers, can be used to fit cylinders that are not meant to go onto a specific engine. 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.
Reviewed in the united states on november 20, 2014. Engine dyno breakin is valuable if you have limited track testing time. Also i heard you can tune your engine by the spark plugs. 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.
We tailor the tuning to any specific requirements for the individual rider by using port direction. We specialise in honda 2strokes, covering the cr range of motorcross bikes, the nsr250 street bikes, and hrc grand prix 125, 250, and 500s. If you want to buy cheap 2 stroke engines, choose 2 stroke engines from. I think this book is the best book for 2 stroke engine builders and tuners to start out with. Geared specifically for gp and kart racers, this hardcover treasure has turned out to be a great reference source for questions on the logic and concepts that pertain to tuning a 2stroke for maximum performance. With this howto guide, you can win the battle with the temperamental twostroke engine.