Part of the problem is understanding the pulse or charge nature of the airflow in a 2 stroke engine. Petals reed valve 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. Open ofice doesnt allow macros though which makes program usage a bit more time consuming. Service masterlist for 2 strokes finish line engines. When set to calculate duration fig 2, you enter the port height adjustments. Not all porting is the same even the word porting has been mis used over the years. Two stroke cylinder porting tips watch this before you start cutting. You can also save and load the data by using the provided functions. Careful care must be taken to assure that engine will not end up making less power then it did before the engine porting was done. The worlds leading 2stroke engine simulation software for 3. This cylinder has two exhaust ports and five transfer ports so enter 2 in the no.
Here is the official description for 2 stroke wizard tuned pipe. The computer allows us to compare the variables with existing. Another quick note on 2 strokes you can change the dynamics and power of a 2 stroke engine a lot just with simple porting. Each part of the 2stroke cycle can be evaluated and designed with computer software programs. 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. 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. Use this mode if you would like to see the effect of crank size, or rod length changes on the port durations. Rk tek uses the latest in 2 stroke design and simulation software, coupled with, practical knowledge that can only be gained through experience and trial and error, to properly modify any engine. We call upon twostroke genius ted boyko for the final word. Two stroke engine porting zmod for android apk download. 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. Fink is open source distribution software specifically designed for porting applications in mac os x. But because of the limited worldwide activity in twostroke engine development, program sales were limited and further development was curtailed.
The morbidelli 125 twin road racer is a rotary valve engine. I have been fascinated with 2 strokes for years but never knew much about how they really worked ports, squish, head design, reeds, etc, etc. The following are spreadsheets for different aspects of 2 stroke designmodification. Two stroke engine and exhaust design software north. Using apkpure app to upgrade two stroke engine porting zmod, fast, free and save your internet data. After our trial and test, the software was found to be official, secure and free. What distance from the edge of the exhaust port is the temp measured at when the parameter is entered. A dremel is for wood working or engraving your favorite paper weight, but not for porting and polishing on a 2 stroke. Calculates port heights from durations, or durations from port heights. Scavenging system redesign is more accurate, and doing so can entail complete overhauls of cylinder designs.
The exhaust port opens and combustion gas starts down the pipe at supersonic speeds. Crankcase and cylinder porting is probably the most controversial subject among performance 2 stroke engine builders. The piston crown opens and closes the exhaust and transfer ports. Processors with a lower number of cores will run the motax expansion chamber optimiser, as will the latest. I didnt mess around with the porting yet, but a good port job combined with a tuned pipe work far better than just a tuned pipe by itself.
An excellent academic book on the theory behind performance tuning for 2stroke motorcycles. In the design form first select the water cooled and reed induction options from the dropdown menus. Download my free calculators spreadsheet to check your computers ability. Bimotion 2stroke software has been commercially available and in professional use since 1991. 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. A simple 3 stage two stroke exhaust calculator based on formulas of g. Double cut cylinder shape with radius end sf5l4, size. Dynomationtwostroke engine simulation motion software, inc. 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. Im working on gathering enough parts to build a triple cylinder rd400 and at some point ill need to sort out the porting and exhaust. Download this app from microsoft store for windows 10 mobile, windows phone 8. Porting and polishing twostroke motorcycle engines.
The cylinder pressure drops, and the fresh charge transfers thru the transfer ports, over the top of the piston, and out the. Crankcase and cylinder porting is probably the most controversial subject among performance 2stroke engine builders. I only have a dremel and was wondering if i could do anything at all myself to my yz125 before i put it together. Two stroke designmodification software the following are spreadsheets for different aspects of 2 stroke designmodification. Many things will affect the power delivery of twostroke motorcycle engines. We use computer design software to maximize power and torque at any elevation. Ive been waiting to open up my 07 cr250 engine for about 18 months now, pretty much since the day i bought it. Porting and trenching twostroke engine cases duration. Alvarsson also informed me that he sends out free updates to bimotion software programs to its owners. Diy cr250 engine porting honda 2 stroke thumpertalk. The description 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. Some 2 stroke porting enhancements you can make to make airflow better in your engine with simple tools. 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. This toolkit offers some basic two stroke engine calculators in hand but also extends to some advanced as well tuning menu.
It is pretty simple to use provided you have all the data and seems to be pretty accurate from any checks i have done. Im going to show you my single skidoorotax 33578mm x 70mm vs my skidoorotax 340 tnt78mm x 70mm intake ports for comparison. Software for fine tuning and design of two stroke engine. Port matching, porting and trenching twostroke engine cases. After entering the stroke and rod length, select either field to calculate. The litterature on which the website is based on, are the books. Changing the power of 2stroke engine is really very simple when you know the basic techniques of 2stroke engines. 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. This means that to run motax, you will need a post 2010 computer which is preferably a desktop, driven by an intel i7 4core processor. 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. Files are great for busting out of prison or maybe a gal to do her nails, but not for professional porting of any kind. The software in addition to defining the geometry of the insert, it also indicates the processing steps for its craft realization. The businesses and individuals that purchased the original dynomation 2 stroke program were pleased with the capability and accuracy of the software.
If this is your first visit, be sure to check out the faq by clicking the link above. The other is how air density barometric pressure, temp, humidity, and elevation change, affects horsepower. Free download here this program is not a part of mota, but it has been put together by the same engineers as a starting point for those wishing to begin from scratch. The program calculates the new durations based on the port height adjustments, stock cylinder specs, and barrel height. Processors with a lower number of cores will run the motax expansion chamber. Two cycle engine port timing calculator csgnetwork. Free 2 stroke expansion chamber calculator software update. We now have a simple 2 stroke expansion chamber design program. Our porting leads the way in performance and technology.
The newest info i have is the twostroke tuners handbook by gordon jennings. 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. Has any one done any kind of porting or polishing to a 2 stroke cylinder themselves. Small values of kh are best suited to grand prix engines with narrow. Really cool two stroke cylinder porting software youtube. 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. Part of the problem is understanding the pulse or charge nature of the airflow in a 2stroke engine. By combining designs which degner brought from mz with japanese technology in the field.
This coefficient kh is called the horn coefficient, with typical values between one and two. 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. Bigger carburetors, higher compression ratios, altered port. We are known to use huge amounts of epoxy to redesign transfer tunnels to make power where the. Great book, but ill guess the world has moved past that info. Port timing basics airgasoline enters the engine from the carburetor at a ratio close to 15. Our goal is to achieve the biggest power gains as possible, while maintaining reliability on your 2stroke engine. Since modifying the 2stroke engines require not only a big. Contemporary twostroke technology was introduced initially to suzuki, and later to yamaha in japan when ernst degner defected from east germany to join suzuki.