The cost to convert this program into a full windows program like our dynomation5, four stroke simulation would prevent it from ever being released. The website does not intend to compeed with any other website dealing with 2 stroke tuning, and the information shared is not at all as thorough as what you can get from reading the books. You should read about how the two stroke enigne works before you attempt this. These two ports are situated between the normal schnurle ports and the exhaust port, at a similar angle to the main transfer ports. In the model tuning tips chapters of this book, all the head specs. Books on tuning and repairing twostroke engines including read valve, rotary valve and vintage pistonport engines twostroke engines books on tuning and repairing twostrokes. Software for fine tuning and design of two stroke engine. Its possible to succeed quite well without any particular knowledge though, since the program contains a lot of recommended values for different tuning degrees. Measurement using a threedimensional anemometrictester was made for the gas flow inside the cylinder of a two stroke engine while the shape of the transfer port was modified.
Basic 2 stroke tuning by eric gorr changing the power band of your dirt bike. In order to optimize an engine and to find initial settings for a tuned pipe exhaust system, on must determine the timing of the engine. Generally, you will also need to rejet your carburetor to allow a greater volume of fuelair mixture to enter your. We specialise in honda 2 strokes, covering the cr range of motorcross bikes, the nsr250 street bikes, and hrc grand prix 125, 250, and 500s. The piston crown opens and closes the exhaust and transfer ports. With the traditional lubrication technique of mixing oil into the fuel, they also have the advantage of working in any orientation, as there is no oil reservoir dependent on gravity. But once you get through it, 2 stroke engines will be as familiar to you as your own hands. 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. Enthusiasts, tuners, mechanics, gp, drag racing, mx, enduro. He is in my view a good candidate for reading due to his knowledge of vintage and modern 2 stroke piston port engines.
Two stroke cylinder porting tips watch this before you. The timing of the transfer and exhaust ports is a key factor controlling the performance characteristics of a two stroke engine. Go to lean on fuel and youll get detonation near the exhaust port which will be the cause of seizure. The trend in high performance two strokes has continued towards more case volume, however each engine and application differ. Two stroke tuner s 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. Very interesting book, lots of great insights and tidbits of knowledge even for those who dont plan to tune any two strokes any time soon. The old adage of stuffing cases on every project just isnt true any more. This simple tool is designed to give you accurate data so you can tune your bike to its full potential. The 2stroke high speed diesel engine concept was investigated in 1999.
Simple twostroke cylinder porting tutorial youtube. Here we are tuning a yz80 motocross engine for use in a motorcycle road racer. Graham bell is an acknowledged expert on engine tuning, with many years experience in this field. The people in the market to buy it are looking for information and the people in the market of selling it are hiding information on porting.
If you are aiming for these qualities, modifying your 2stroke engine is a great strategy. Basic 2 stroke tuning changing the power band of your dirt bike engine is simple when you know the basics. Well i have been reminded lately that this is a dirtbike forum where i can ask questions so i figured id give it a shot. Dynomatontwostroke is a dosbased simulation that was originally released in the mid1990s. The first thing you need to do when tuning a two stroke is to determine its characteristics. You should only rely on the experience of the very best. A dremel or some old files will not yield good results. For port work, one company that will help you is 2stroke porting. Advances in the design of twostroke, high speed, compression.
It enters via the intake port as the piston rises into the crankcase and then is transferred to the combustion area via the transfer ports as the piston descends and the piston top uncovers the. Doing the finishing touches on the spx cylinder and wanted to give you a quick tour of my porting setup. For port work, one company that will help you is 2strokeporting. Has any one done any kind of porting or polishing to a 2 stroke cylinder themselves. Two stroke cylinder porting tips watch this before you start cutting. The twostroke engine is a common power source for small and. Tips on how to port a two stroke cylinder, what to donot do and how to do it right. Cc specialty tools porting and polishing for 2 stroke engines. You dont need fancy expensive stuff to port two stroke cylinders, you can get by with.
Two stroke performance tuning chapter 3 porting and cylinder scavenging. Although there is really no shortage of books on the subject of 2stroke tuning and preparation, i knew that an active software programme would be able to offer so much more. Jennings book talks about port time area and porting the cylinder to have peak efficiency at a certain rpm. Our 1mc, the worlds best know right angle porting tool. Oct 04, 2011 changing the power of 2 stroke engine is really very simple when you know the basic techniques of 2 stroke engines. However, you shouldnt just pick any business that you can find anywhere. Twostroke waveaction engine simulation motion software. Once the piston uncovers the side transfer and rear boost port, the arriving lowpressure vacuum pulse from the exhaust draws airfuel up into the combustion chamber. While two stroke engine development is on the rise again, the worldwide interest in a professional two stroke engine simulation is still limited.
If you are aiming for these qualities, modifying your 2 stroke engine is a great strategy. The most common mistake is to choose the wrong combination of engine components, making the engine run worse than stock. We specialise in honda 2strokes, covering the cr range of motorcross bikes, the nsr250 street bikes, and hrc grand prix 125, 250, and 500s. Fully revised this book takes the reader through the various modifications that can be made to a twostroke engine and its components to give maximum useable. A myriad of different aftermarket accessories is available for you to custom tune your bike to better suit your needs. Other books to his credit are modern engine tuning, two stroke performance tuning and forced induction performance tuning. There are some very good two stroke tuning guides from.
The inlet port opens 30 after bdc and closes 79 after tdc. Most of the errors is to choose a less appropriate combination of engine components so that the engine actually ran worse than standart, ever experienced. With 2 stroke engine modification, porting and polishing is the ultimate choice. Oct 17, 2017 tips on how to port a two stroke cylinder, what to donot do and how to do it right. 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. John i believe you have it correct in the cooling benifit for the piston crown. You should also be sure of the size of the cuts you make, as removing too much metal from any port can render the cylinder useless. Port timing basics airgasoline enters the engine from the carburetor at a ratio close to 15. This is in contrast to a fourstroke engine, which requires four strokes of the piston to complete a power cycle during two crankshaft revolutions. Other books to his credit are modern engine tuning, twostroke performance tuning and forced induction performance tuning. My porting setup affordable and functional 2 stroke tuning. Unless you are very good then the only port that makes much difference is the exhaust. Good resources on cylinder porting and tuning in general include jennings two stroke tuners handbook, and two stroke performance tuning by a graham bell.
What is the use of transfer ports in a twostroke engine. Oct 21, 2011 i just got my engine to today and all ready have it striped down anyways i have shaved the head to the fin and bump it up by 1. An engine port is an open window in the cylinder wall for the intake or exhaust of fuel mixture airgas. The process of cylinder porting is a funny paradox. Changing the power of 2stroke engine is really very simple when you know the basic techniques of 2stroke engines. If you cannot reach all of the port you are attempting to work on, then forget it or find someone who can. The first issue to address is jetting and carburettor tuning. Introduction the program is intended for both amateurs and professionals with basic knowledge about the 2stroke cycle and its pulse dependency. I made this video long ago, but forgot to upload it. Feb 08, 20 well i have been reminded lately that this is a dirtbike forum where i can ask questions so i figured id give it a shot. I was reading a thread about a 2 stroke versus a 4 stroke and it occurred to me that if the porting, or timing, of a 2 stroke could be changed, that maybe its maximum torque range could be lowered to an rpm comparable to the 4 stroke, and thus swing the same prop as the 4 stroke.
Since modifying the 2stroke engines require not only a big. A rare technical guide to the fundamentals of the crank train, cylinder heads, expansion chambers, port timing, crankcase pumping, carburetion and ignition. Professional grade 2 stroke porting and polishing kit includes. 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. Two stroke moped tuning two stroke timing moped tuning. Graham bell starts off by saying that he doesnt believe port time area and its all about the duration the ports are open.
The relationship between port shape and engine performance. Airgasoline enters the engine from the carburetor at a ratio close to 15. Everyday low prices and free delivery on eligible orders. A man named aaen olav aaen performance had some published work about piston port 2 stroke technology and performance. If your looking for the best from your 2 stroke mad biker designs has its own dedicated tuning arm under mad biker developments not content with being one of the premier parts suppliers in the uk from world renowned companies, such as brembo, dymag, samco to name but a few. Blair of queens university belfast, and published by the society of automotive engineers. Racingsm software has features for many different areas 2 stroke exhausts development, drag racing features, simulators, carburetor tuning, connectingrod analysis etc with all this knowhow along with lufo racing heritage, we believe this is a very fair price. Turbo and even supercharger setups of various configurations can be very useful, however, they are often more complicated with 2 stroke tuning than with 4 stroke applications on a tangent, i did witness a 50cc turbo 2 stroke bike that would do over 150mph, but i digress. Geoff batticks notes on 2 stroke engine modification. Two stroke petrol engines are preferred when mechanical simplicity, light weight, and high powertoweight ratio are design priorities. 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.
Dec 09, 2017 doing the finishing touches on the spx cylinder and wanted to give you a quick tour of my porting setup. Tuning and jetting honda, ktm, kawasaki, yamaha, suzuki, husaberg, husqvarna, tm, gas gas. There are three ports are present in the two stroke cycle engine. The morbidelli 125 twin road racer is a rotary valve engine. By using the torqsoft exhaust timearea programme, it was possible to raise the power output of the engine by 10% just by a simple modification to the exhaust port. Jenning vs graham bell, 2 stroke tunning books motorcycle.
Designed to check for air leaks in 2 stroke engines includes air pressure gauge, pumpup bulb and most fittings and adapters for single and twin cylinder 2 stroke motorcycle engines packed in a convenient carry box, complete with instructions made in the u. Exhaust port the diagram which shows the position of crank at which the above ports are open and close are called as port timing diagram. With 4 stroke engines, porting, when performed correctly and with the right tools, will result in positive horsepower gains, along with increased fuel efficiency and a smoother running engine. I only have a dremel and was wondering if i could do anything at all myself to my yz125 before i put it together. After removing your cylinder head and orings, a simple measurement is taken by placing the gage over your exposed piston in the. Those of us who have grown up in the japanese two stroke. Setting the correct piston protrusion and squish volume is imperative to tuning the modern 2 stroke race motor.
The information used in the programs calculations was taken from the books the basic design of the two stroke engine and the book design and simulation of two stroke engines. Goodreads helps you keep track of books you want to read. Developed by pedro, with more than 20 000 lines of code, all the knowhow applied to software comes from us and also a lot from the legendary portuguese 2stroke tuner lufo racing, this software is directed for all 2stroke. Many modern reedvalve 2strokes have a rear boostport running up from the intake port to the same height as the transfers. Nov 11, 2010 jennings book talks about port time area and porting the cylinder to have peak efficiency at a certain rpm. 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. These kits replace your cylinder and piston with a larger bore. In motocross its usually a compromise between best peak hp and good early off the pipe power. Quite a few good 2 stroke have been done that way in the past. So much myth and misinformation is associated with this complex machining and metal finishing process. Each intake port can be locked to a fixed timing relation with the exhaust port.
With 100% more flow area with we need less blowdown timing to mach the wider area cross section. There is one or more forwardlocated exhaust ports, two or more side transfer ports, and one rear intake port. The relationship between port shape and engine performance was investigated for various factors that characterize the flow. The only problem is finding his books due to them being discontinued and published only for a short period. Scavenging ports optimal design of a twostroke small. So now its close to 66%23rds of the bore instead of one rd with the single port exhaust thats 100% more area. Contents chapter 1 introduction 9 chapter 2 the cylinder. Thank you for your interest in dynomationtwostroke designed for windows98xp. 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. Apr, 2015 has any one done any kind of porting or polishing to a 2 stroke cylinder themselves.