Intake the fuelair mixture is first drawn into the crankcase by the vacuum that is created during the upward stroke of the piston. Port matching, porting and trenching twostroke engine cases. 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. Our example has an after market 50cc performance cylinder with a bridged exhaust port.
The 14sr kit is the 2 stroke porting kit for 100cc and under mx bikes, chainsaws, scooters, mini bikes, rc vehicles, dirtbikes, and all small displacement 2 strokes. But because of the limited worldwide activity in two stroke engine development, program sales were limited and further development was curtailed. We believe that using this software will help your 2 stroke development or racing results on different types of competition. There are many ways to boost the power, one of which is by installing a tuned pipe. There is one or more forwardlocated exhaust ports, two or more side transfer ports, and one rear intake port. Millennium technologies provides repair and maintenance services for cylinders and cylinder heads, and manufactures nickel silicon carbide plated cylinders for a variety of engines, including motorcycles, snowmobiles, race cars, karts, dirt bikes and watercraft. Heres how shaving off miniscule ammounts of metal can drastically improve your speed. This, coupled with their lighter, simpler construction, makes the two stroke engine popular in chainsaws, line trimmers, outboard motors, snowmobiles, jetskis, light motorcycles. Part of the problem is understanding the pulse or charge nature of the airflow in a 2stroke engine. Two cycle engine port timing calculator csgnetwork.
Test your own theories on porting and exhaust pipe design. As far as emissions are concerned, the behavior of this two stroke engine does. Cfd modelling of a two stroke engine to predict and reduce. Stock engine parameters are entered on the top row of controls. Pipes, silencers, carburetors, reeds and valves are all popular bolton modifications. After all of this is done, you have successfully matched your engines ports. Moreover, interest factors like the port parameters are computed even if the. This 2 stroke engine animation, article and diagrams are courtesty of.
Two stroke engine porting zmod this software made for help out team in first time, but some friend advise this is the time to share. They are so simple and fun that ive always enjoyed tinkering with them. 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. The result was 25hp at the rear wheel with the engine coming on the pipe at 7000 revsmin and producing usefull power to 1 revsmin using the original cast iron 125cc. I only have a dremel and was wondering if i could do anything at all myself to my yz125 before i put it together. A singlecylinder, loopscavenged, sparkignition, twostroke engine extensively used for.
However, you shouldnt just pick any business that you can find anywhere. A dremel is for wood working or engraving your favorite paper weight, but not for porting and polishing on a 2 stroke. Porting and polishing two stroke motorcycle engines. After entering the stroke and rod length, select either field to calculate. By this i mean intake port to intake manifold, transfer ports to engine case, and exhaust port to exhaust header flange. You should only rely on the experience of the very best. What you have accomplished up to this point will definitely allow your engine to run smoother, stronger, and more efficient. It will simulate one of the cylinders of a multicylinder two stroke engine provided that the cylinders are identical in layout and dimensions and each cylinder has a seperate exhaust and induction system. I see a lot of people asking questions about porting feel free to add to this thread all you fellow modders first things first here you got to understand how 2 stroke engines operate just because you know the basics dont mean nothing here is a. Softengine dynamometers and engine simulation software. The higher resolutions will give finer port outlines, but you must have photo software that will allow you to print in actual size.
Dynomationtwostroke engine simulation motion software, inc. Bigger carburetors, higher compression ratios, altered port timings and expansion. Porting and polishing twostroke motorcycle engines. Advances in the design of twostroke, high speed, compression. Simple twostroke cylinder porting tutorial youtube.
For port work, one company that will help you is 2strokeporting. 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. Sometimes an engine can benefit from a nondivergent header, especially if the port is relative large or not state of the art. Port timing basics airgasoline enters the engine from the carburetor at a ratio close to 15. We also have a simple 2 stroke expansion chamber design program. A 2 stroke engine is an engine in which there are 2 phases in a cycle of operation of the engine. Mota 2stroke engine simulation software beven d young. The other is how air density barometric pressure, temp, humidity, and elevation change, affects horsepower. Position the red slide switch, located to the left of the displays, in line with. Hey guys, getting ready for a few saw builds, and am a bit new to the saw world not new to engine building ported many a 4 stroke, and some 2 stroke dirt bike, banshee, etc. No previous knowledge of the two stroke cycle engine is required just input the required data and then run mota to set in motion this powerful process. 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. Really cool two stroke cylinder porting software youtube. Specialty tools for porting 2 stroke, 4 stroke, cylinders, cylinder heads, 2 stroke case porting, and intakes.
The businesses and individuals that purchased the original dynomation 2 stroke program were pleased with the capability and accuracy of the software. Have the specifications for the porting in hand just need an expert to do the job. Low exhaust emission system for small two stroke cycle engines yoshio kobayashi 1 kazuyuki uenoyama yukiteru yoshida1 kazunori kudo 2 hiroyuki endo3 emission regulations for small utility, lawn, and garden equipment engines went into effect in 1995 in the u. A singlecylinder, loopscavenged, sparkignition, two stroke engine extensively used for. Contemporary twostroke technology was introduced initially to suzuki, and later to yamaha in japan when ernst degner defected from east germany to join suzuki. Apr, 2015 has any one done any kind of porting or polishing to a 2 stroke cylinder themselves. The high performance 2 stroke engine is a pulse resonance engine which means that the operation in general and the scavenging in particular is not only. Part of the problem is understanding the pulse or charge nature of the airflow in a 2 stroke engine. Mspec twostroke performance services millennium tech. Performance porting of vintage 2strokes vintage dirt. The worlds leading 2stroke engine simulation software for 3.
You can print the image on transparancy film to use as a porting. 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. Files are great for busting out of prison or maybe a gal to do her nails, but not for professional porting of any kind. Calculates port heights from durations, or durations from port heights. 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. Basic 2 stroke tuning by eric gorr changing the power band of your dirt. Jul 18, 2017 porting and polishing two stroke motorcycle engines. By combining designs which degner brought from mz with japanese technology in.
Cylinder heads, as manufactured, are usually suboptimal for racing applications due to design and are made for maximum durability hence the thickness of the walls. The software does complete cycle simulation of the whole internal combustion process including the gasdynamics in the pipesducts, ports and plenums air boxes, boost bottles, exhaust boxes etc. Edge chamfering and cylinder porting for two stroke engines edge chamfering is a surface finishing technique that smoothes the edges of cylinder ports so that piston rings seat properly. In motocross its usually a compromise between best peak hp and good early off the pipe power. You can choose to have the program calculate either required port height adjustments, or port durations. A myriad of different aftermarket accessories is available for you to custom tune your bike to better suit your needs. Performance porting of vintage 2strokes vintage dirt bikes. Below the stock engine parameters are displays for input and output of porting information. Four stroke porting and performance finding reliable, quality power you can feel on modern four strokes is very challenging.
You should read about how the two stroke enigne works before you attempt this. I dont know of any site that gives that information but there are many 2 strokes designed to give high torque at low revs. The trend in high performance two strokes has continued towards more case volume, however each engine and application differ. For our design example we are going to design an exhaust system for a 50cc minarelli am6 engine. Now, you can either be satisfied with everything at this point, or, you can choose to get more detailed and do some more indepth porting. Computer design software is used to calculate the msv for head. It clearly shows the air fuel mixture as a green mist while entering the engine through the intake track.
Jun 24, 2007 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. Engine geometry is modeled using commercial proe software. Two stroke design software the following are spreadsheets for different aspects of 2 stroke designmodification. Purchase the porting tools you need at our online store. Using our flow bench, dynomometer, and advanced computer simulation software along with hard work and testing, we offer industry leading performance. Has any one done any kind of porting or polishing to a 2 stroke cylinder themselves.
Cylinder porting, a related technique, is designed to improve flow characteristics and promote optimum engine. If you are aiming for these qualities, modifying your 2stroke engine is. Determine the level of porting you wish to achieve before you start cutting or grinding. These are the engines used in cl stunt where we swing large props at quite low revs, usually around 8000 and in a 4 stroke mode. A sydney engineering company has developed a new twostroke engine that they believe could be used in motorcycles. Many things will affect the power delivery of twostroke motorcycle engines. These modifications can be extremely effective when used in the right combinations.
Harris performance engineering hp race development. The main use of motion dynamics in a gas engine to generate power. Port matching, porting and trenching twostroke engine cases duration. Since the two stroke engine fires on every revolution of the crankshaft, a two stroke engine is usually more powerful than a four stroke engine of equivalent size. Stroke basically, means the sudden movement of piston which is converted into a rotary motion at crankshaft. Edge chamfering and cylinder porting for twostroke engines. Mota software, 2 stroke engine simulation software, 2 stroke exhaust design. Cfd modelling of a two stroke engine to predict and reduce short circuit losses 2015320702 one of the major reason for lower efficiency and higher unburned hydrocarbon and carbon monoxide emission for two stroke engine is short circuit losses during the scavenging process. Two stroke cylinder porting tips watch this before you start cutting. But because of the limited worldwide activity in twostroke engine development, program sales were limited and further development was curtailed. 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. Porting and trenching two stroke engine cases runtime 25. Looking to find an experienced and reliable person to upgrade the performance of my honda mr175.
Basic 2 stroke tuning changing the power band of your dirt bike engine is simple when you know the basics. Assign fixed relationships between transfers and exhaust port. The way a two stroke motor works causes them to be f. Crankcase and cylinder porting is probably the most controversial subject among performance 2stroke engine builders.
This water cooled, reed induction engine is used in a variety of 50cc production road bikes such as the aprilia rs50, yamaha tzr 50 and the rieju. A few cars have used this engine too, such as the wartburg knight and some early saabs. Cylinder head porting refers to the process of modifying the intake and exhaust ports of an internal combustion engine to improve quantity of the air flow. I made this video long ago, but forgot to upload it. Our goal is to achieve the biggest power gains as possible, while maintaining reliability on your 2 stroke engine. Aussie twostroke engine invention motorbike writer. Pete tibbitts emerged victorious with his torqsoft designed exhaust system.
This will get you started by providing, for your engine, the dimensions of an expansion chamber with a 2 stage or 3stage diffuser. Sep 30, 2012 hi performance two stroke porting software program. The most common mistake is to choose the wrong combination of engine components, making the engine run worse than stock. Ted boyko began porting cylinders 45 years ago, when the twostroke craze was at its peak, and hes still at it today. Once thought too polluting, the twostroke engine makes a comeback in advance of stricter fuel efficiency standards. Although invisible to the machine 2 is more simple than 4 stroke engines, with very few components, only the piston within the cylinder, but actually not very complex machine 2 in the calculation. Bsa bantams only have three gears and thus the exhaust design had to give a wide power band.
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. Test engines with pistonport induction, reedvalve induction, or rotaryvalve induction. Millions of fluid and thermodynamic calculations are made by mota representing the conditions inside your two stroke engine throughout its complete operating cycle. A two stroke 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. Two stroke engines often have a high powertoweight ratio, power being available in a narrow range of rotational speeds called the power. Crankcase and cylinder porting is probably the most controversial subject among performance 2 stroke engine builders. 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.
If you are aiming for these qualities, modifying your 2 stroke engine is a great strategy. At the moment, we have a special 2 stroke bike collection. We have the optimum case modifications to suit each application and engine developed over countless hours. Some smaller engines, however, notably those fitted to some mopeds or motorcycles, operate on a two stroke cycle the piston is on a power stroke every time it moves down the cylinder so the crankshaft turns only once during each cycle. How to tips from tj on porting and polishing 2 strokes. There is no 2 stroke displacement limit for our software, for example you can have a 125, 250, 500, 700 singlecylinder and our modules will work flawlessly. Tier 2 standards of the california air resource board carb went into effect in. Mota and its related set of programs have been developed to simulate the performance of highoutput single cylinder two stroke engines. If you are aiming for these qualities, modifying your 2stroke engine is a great strategy.
Dependability, durability and race track proven 2 stroke cylinder porting come in 3 stages, we can set you up with a package or custom port a cylinder just for your application. Hi performance two stroke porting software program youtube. Airgasoline enters the engine from the carburetor at a ratio close to 15. Low exhaust emission system for small twostroke cycle. An engine port is an open window in the cylinder wall for the intake or exhaust of fuel mixture airgas. Its called crankcase independent twostroke cits and was invented by former south african motorsport engineer basil van rooyen, director of cits engineering, st ives. Head machining to suit unleaded or race fuel to get a perfect burn from your engine. Does anyone have any recommendations for individuals or companies the will do porting on vintage 2 stroke engines. Cc specialty tools will always be the company to go to for all your porting and polishing tools and equipment.