Porting and polishing two stroke motorcycle engines. 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. Two cycle engine port timing calculator csgnetwork. Hi performance two stroke porting software program youtube. How to tips from tj on porting and polishing 2 strokes. Pipes, silencers, carburetors, reeds and valves are all popular bolton modifications.
Specialty tools for porting 2 stroke, 4 stroke, cylinders, cylinder heads, 2 stroke case porting, and intakes. Porting and polishing twostroke motorcycle engines. Tier 2 standards of the california air resource board carb went into effect in. We use computer design software to maximize power and torque at any elevation. 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.
After entering the stroke and rod length, select either field to calculate. Sometimes an engine can benefit from a nondivergent header, especially if the port is relative large or not state of the art. Basic 2 stroke tuning by eric gorr changing the power band of your dirt. We believe that using this software will help your 2 stroke development or racing results on different types of competition. Porting and trenching two stroke engine cases runtime 25. 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.
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. 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. Stroke basically, means the sudden movement of piston which is converted into a rotary motion at crankshaft. 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. Two stroke engines often have a high powertoweight ratio, power being available in a narrow range of rotational speeds called the power. Using our flow bench, dynomometer, and advanced computer simulation software along with hard work and testing, we offer industry leading performance. By this i mean intake port to intake manifold, transfer ports to engine case, and exhaust port to exhaust header flange. Cfd modelling of a two stroke engine to predict and reduce. 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. 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. Many things will affect the power delivery of two stroke motorcycle engines. Simple twostroke cylinder porting tutorial youtube. 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.
Advances in the design of twostroke, high speed, compression. 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. Harris performance engineering hp race development. Looking to find an experienced and reliable person to upgrade the performance of my honda mr175. Intake the fuelair mixture is first drawn into the crankcase by the vacuum that is created during the upward stroke of the piston. A 2 stroke engine is an engine in which there are 2 phases in a cycle of operation of the engine. It clearly shows the air fuel mixture as a green mist while entering the engine through the intake track. 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. This kit is one of the best options for doing mx and dirt bikes of the 100cc, 80cc, 70cc, 50cc, and even down to 30cc, 2 stroke variety. There is one or more forwardlocated exhaust ports, two or more side transfer ports, and one rear intake port. Sep 30, 2012 from beginners in porting,to brazen speed phreaks, this is a great tool if your not a molecular, thermohydrus calculus genius space physicist math scientist. These modifications can be extremely effective when used in the right combinations. A singlecylinder, loopscavenged, sparkignition, twostroke engine extensively used for.
Two stroke design software the following are spreadsheets for different aspects of 2 stroke designmodification. Files are great for busting out of prison or maybe a gal to do her nails, but not for professional porting of any kind. A myriad of different aftermarket accessories is available for you to custom tune your bike to better suit your needs. At the moment, we have a special 2 stroke bike collection. 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.
A singlecylinder, loopscavenged, sparkignition, two stroke engine extensively used for. Port timing basics airgasoline enters the engine from the carburetor at a ratio close to 15. 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. Really cool two stroke cylinder porting software youtube. This will get you started by providing, for your engine, the dimensions of an expansion chamber with a 2 stage or 3stage diffuser. A sydney engineering company has developed a new twostroke engine that they believe could be used in motorcycles. Performance porting of vintage 2strokes vintage dirt bikes. Sep 30, 2012 hi performance two stroke porting software program. As far as emissions are concerned, the behavior of this two stroke engine does. The worlds leading 2stroke engine simulation software for 3. Its called crankcase independent twostroke cits and was invented by former south african motorsport engineer basil van rooyen, director of cits engineering, st ives. I only have a dremel and was wondering if i could do anything at all myself to my yz125 before i put it together. You can choose to have the program calculate either required port height adjustments, or port durations.
Calculates port heights from durations, or durations from port heights. The trend in high performance two strokes has continued towards more case volume, however each engine and application differ. Cylinder porting, a related technique, is designed to improve flow characteristics and promote optimum engine. A few cars have used this engine too, such as the wartburg knight and some early saabs. Aussie twostroke engine invention motorbike writer. 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.
Port matching, porting and trenching twostroke engine cases duration. In motocross its usually a compromise between best peak hp and good early off the pipe power. Apr, 2015 has any one done any kind of porting or polishing to a 2 stroke cylinder themselves. The other is how air density barometric pressure, temp, humidity, and elevation change, affects horsepower. Edge chamfering and cylinder porting for twostroke engines. Bsa bantams only have three gears and thus the exhaust design had to give a wide power band. Mspec twostroke performance services millennium tech. Assign fixed relationships between transfers and exhaust port. But because of the limited worldwide activity in two stroke engine development, program sales were limited and further development was curtailed. 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. Port matching, porting and trenching twostroke engine cases. Four stroke porting and performance finding reliable, quality power you can feel on modern four strokes is very challenging. The higher resolutions will give finer port outlines, but you must have photo software that will allow you to print in actual size. Has any one done any kind of porting or polishing to a 2 stroke cylinder themselves.
For our design example we are going to design an exhaust system for a 50cc minarelli am6 engine. Determine the level of porting you wish to achieve before you start cutting or grinding. Our goal is to achieve the biggest power gains as possible, while maintaining reliability on your 2 stroke engine. If you are aiming for these qualities, modifying your 2stroke engine is. Test your own theories on porting and exhaust pipe design. Pete tibbitts emerged victorious with his torqsoft designed exhaust system. 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. Engine geometry is modeled using commercial proe software.
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. Purchase the porting tools you need at our online store. You should read about how the two stroke enigne works before you attempt this. Part of the problem is understanding the pulse or charge nature of the airflow in a 2stroke engine. If you are aiming for these qualities, modifying your 2 stroke engine is a great strategy. After all of this is done, you have successfully matched your engines ports. Jul 18, 2017 porting and polishing two stroke motorcycle engines.
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. The way a two stroke motor works causes them to be f. Head machining to suit unleaded or race fuel to get a perfect burn from your engine. I dont know of any site that gives that information but there are many 2 strokes designed to give high torque at low revs. Softengine dynamometers and engine simulation software. 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. Position the red slide switch, located to the left of the displays, in line with.
Crankcase and cylinder porting is probably the most controversial subject among performance 2stroke engine builders. 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. You should only rely on the experience of the very best. 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. Once thought too polluting, the twostroke engine makes a comeback in advance of stricter fuel efficiency standards.
I made this video long ago, but forgot to upload it. Millions of fluid and thermodynamic calculations are made by mota representing the conditions inside your two stroke engine throughout its complete operating cycle. 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. Have the specifications for the porting in hand just need an expert to do the job. Many things will affect the power delivery of twostroke motorcycle engines. Stock engine parameters are entered on the top row of controls. Below the stock engine parameters are displays for input and output of porting information. Part of the problem is understanding the pulse or charge nature of the airflow in a 2 stroke engine. Cc specialty tools will always be the company to go to for all your porting and polishing tools and equipment. The businesses and individuals that purchased the original dynomation 2 stroke program were pleased with the capability and accuracy of the software. But because of the limited worldwide activity in twostroke engine development, program sales were limited and further development was curtailed. 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. Our example has an after market 50cc performance cylinder with a bridged exhaust port. 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.
Ted boyko began porting cylinders 45 years ago, when the twostroke craze was at its peak, and hes still at it today. The most common mistake is to choose the wrong combination of engine components, making the engine run worse than stock. You can print the image on transparancy film to use as a porting. A dremel is for wood working or engraving your favorite paper weight, but not for porting and polishing on a 2 stroke. 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. Heres how shaving off miniscule ammounts of metal can drastically improve your speed. 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.
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. Airgasoline enters the engine from the carburetor at a ratio close to 15. Moreover, interest factors like the port parameters are computed even if the. 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. 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. Two stroke cylinder porting tips watch this before you start cutting. Mota 2stroke engine simulation software beven d young. They are so simple and fun that ive always enjoyed tinkering with them.
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. We have the optimum case modifications to suit each application and engine developed over countless hours. Basic 2 stroke tuning changing the power band of your dirt bike engine is simple when you know the basics. By combining designs which degner brought from mz with japanese technology in. If you are aiming for these qualities, modifying your 2stroke engine is a great strategy. Contemporary twostroke technology was introduced initially to suzuki, and later to yamaha in japan when ernst degner defected from east germany to join suzuki. 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. Bigger carburetors, higher compression ratios, altered port timings and expansion. An engine port is an open window in the cylinder wall for the intake or exhaust of fuel mixture airgas.
Low exhaust emission system for small twostroke cycle. This is in contrast to a four stroke engine, which requires four strokes of the piston to complete a power cycle during two crankshaft revolutions. There are many ways to boost the power, one of which is by installing a tuned pipe. 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. Crankcase and cylinder porting is probably the most controversial subject among performance 2 stroke engine builders.
The header interacts a lot with the exhaust port shape, so this angle is dependent on the exhaust port configuration. Effect of ports configuration on trapping efficiency of a twostroke. Mota and its related set of programs have been developed to simulate the performance of highoutput single cylinder two stroke engines. This, coupled with their lighter, simpler construction, makes the two stroke engine popular in chainsaws, line trimmers, outboard motors, snowmobiles, jetskis, light motorcycles. Computer design software is used to calculate the msv for head. Dynomationtwostroke engine simulation motion software, inc. What you have accomplished up to this point will definitely allow your engine to run smoother, stronger, and more efficient. The main use of motion dynamics in a gas engine to generate power. 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. For port work, one company that will help you is 2strokeporting. Does anyone have any recommendations for individuals or companies the will do porting on vintage 2 stroke engines. However, you shouldnt just pick any business that you can find anywhere. Mota software, 2 stroke engine simulation software, 2 stroke exhaust design.