They left casting imperfections all through the transfer ports untouched. With yamaha redesigning the 2015 two stroke line, some of the styling work was done for us, so we got straight to work on the heart of our yz125. We are known to use huge amounts of epoxy to redesign transfer tunnels to make power where the competition wont. With 2 stroke engine modification, porting and polishing is the ultimate choice. Yz250 cylinder porting tech helprace shop motocross. Porting and polishing two stroke motorcycle 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.
Changing the power of 2stroke engine is really very simple when you know the basic techniques of 2stroke engines. If i am unable to contact this gss race porting shop. 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. No one has the real answer as to what is the best port and polish job. The trend in high performance two strokes has continued towards more case volume, however each engine and application differ. Port timing basics airgasoline enters the engine from the carburetor at a ratio close to 15. So i took my pro circuit modified cr250 out for the first time today. The pipe was made in 93 according to the tag and it only has one small dent in it.
The new camshafts provide superior performance upgrades over stock hptorque by optimizing the lobe profile for increased lift and duration. The r304 shorty silencer was developed as a fullrace two stroke silencer and was designed to increase power over stock exhaust. But because of the limited worldwide activity in twostroke engine development, program sales were limited and further development was curtailed. All i can say is wow it is easily the fastest bike i have ever ridden. The information used in the programs calculations was taken from the books a. Purchase the porting tools you need at our online store. Bigger carburetors, higher compression ratios, altered port timings and expansion. The current iwt mr1 pipe for long circuit karting in the 100cc non. Assign fixed relationships between transfers and exhaust port. Since modifying the 2stroke engines require not only a big. Software for fine tuning and design of two stroke engine by.
Pro circuit did the porting,but the crank and rod work was subcontracted to klemm research,excellent tech articles on their website pertaining to engine preparation,compression and leakdown testing,2 stroke oils. Head machining to suit unleaded or race fuel to get a perfect burn from your engine. Like the platinum and works pipe, the platinum 2 offers incredible performance with substantial power gains in the low and midrange part of the powerband to help take your. Apr 29, 2020 the pro circuit 2020 kx250 y radiator hose kit is designed to eliminate the plastic y elbows found in other radiator hoses. While our inhouse motor modifications group deals with porting polishingetc, our pro circuit motor components are products that most ridermechanics can install themselves tel. 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.
An engine port is an open window in the cylinder wall for the intake or exhaust of fuel mixture airgas. 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. I also have a nos seat, gas tank, and stock plastic that has not seen the dirt. I have a factory finish pro circuit exhaust and the fatty pipe is all discolored and i was wondering if the pipe can be restored to the factory finish. Petals reed valve in the 2 stroke 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.
Really cool two stroke cylinder porting software youtube. Dynomatontwostroke is a dosbased simulation that was originally released in the mid1990s. The t6 stainless steel exhaust system offers the same benefits as our popular ti6 titanium exhaust system, but the t6 is constructed of stainless steel and aluminum for increased strength and durability while giving riders a more affordable alternative to titanium. This kit is ideal for porting and polishing small 2 stroke cylinders.
We also have a simple 2stroke expansion chamber design program. By combining designs which degner brought from mz with japanese technology in the field. Pro s dont look at it as the cost of the tools, you look at it as the cost of messing up a cylinder head, the cost of not doing it right and wasting all your time, the cost of getting your butt kicked in a race because you were at a huge disadvantage from not having enough horse power, the cost of all those hours you spent trying to make tools. 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. In extreme conditions, these plastic elbows can melt. Calculates port heights from durations, or durations from port heights. Mota software, 2 stroke engine simulation software, 2 stroke exhaust design. Pro circuit engine porting youtube muhajir asqalani. Great book, but ill guess the world has moved past that info. 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. With yamaha redesigning the 2015 twostroke line, some of the styling work was done for us, so we got straight to work on the heart of our yz125. In the model tuning tips chapters of this book, all the. 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.
After entering the stroke and rod length, select either field to calculate. Everyone has their own style of porting the cylinder. Those of us who have grown up in the japanese twostroke. Each intake port can be locked to a fixed timing relation with the exhaust port. The newest info i have is the twostroke tuners handbook by gordon jennings. The compact design of the short aluminum canister offers optimum performance gains and is recommended for closedcourse racing only.
The idea is to get an education in cause and effect. 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. We now have a simple 2 stroke expansion chamber design program. Basic 2 stroke tuning changing the power band of your dirt bike engine is simple when you know the basics.
He then has put his own programs together and applied to us mx 2 stroke motors. Blair of queens university belfast, and published by the society of automotive engineers. Any body have engine work done by pro circuit and if so do you. Not all porting is the same even the word porting has been mis used over the years. Temps roughly 70 at 600 elavation currently running. Corona, ca april 29, 2020 2020 yz450f riders can always expect the best performance parts from pro circuit and the new camshafts for your yamaha will not disappoint. Fresh v forve reeds running straight 91 non ethonal 32. 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. Brent at tdc 2 stroke has acquired data from from builders all over the world. Pro circuit has built a reputation around our exhaust systems. Porting and polishing twostroke motorcycle engines. I have a 1980 husqvarna 250 cr with pro circuit porting, cut mahle piston, rick asch pipe, internal motoplat, and the canister kit.
So whether you have a 50cc road bike, a 500cc motocrosser or a classic racer, we will design the perfect exhaust system for you. 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 dependent upon the pulses created from piston pumping but also from combustion properties. The worlds leading 2stroke engine simulation software for 3. The fmf fatty was a later design than the older fmf pipes. Cc specialty tools porting and polishing for 2 stroke engines.
Thank you for your interest in dynomationtwostroke designed for windows98xp. 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. The businesses and individuals that purchased the original dynomation 2 stroke program were pleased with the capability and accuracy of the software. In motocross its usually a compromise between best peak hp and good early off the pipe power. They built a transworld test bike back in 03 and rich taylor said it was the best yz 250 motor he tested, and he even tested the factory bikes. Discussion in modded work saws started by whsh, mar 2, 2014. Software for fine tuning and design of two stroke engine. Forum main tech helprace shop yz250 cylinder porting. How to tips from tj on porting and polishing 2 strokes.
The software in question the inexpensive stuff is great for someone who just does not have the math skills to wade through what seem to be a text book of complex formulas. 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. Test your own theories on porting and exhaust pipe design. 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. Find great deals on ebay for pro circuit exhaust 2 stroke. Contemporary two stroke technology was introduced initially to suzuki, and later to yamaha in japan when ernst degner defected from east germany to join suzuki. The ct mid range, the stinger on it is larger than the fmf or pro circuit, so does have an advantage over the other two. Improve the performance of your twostroke engine with a torqsoft designed exhaust system. I just saw this porting and wanted to be a little different and have it done to my cylinder. Bigger carburetors, higher compression ratios, altered port.
The engine was disassembled and the top end sent off to pro circuit for some massaging by mitch payton and his porting tools. Along with being lightweight and able to withstand expanding when hot, pro circuit hose kits are also bright blue in appearance and will stay vibrant and not fade. Pro circuit can justify those setup costs as they sell more than a few. Oct 04, 2011 changing the power of 2 stroke engine is really very simple when you know the basic techniques of 2 stroke engines. This will get you started by providing, for your engine, the dimensions of an expansion chamber with a 2stage or 3stage diffuser. Hex head screws are used to secure the inlet cap and can be removed easily for quick repacking of the silencer. 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. 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. Hey i ride a 2005 yz125 and i was looking into getting a pro circuit engine mod for my ride. Pro circuit porting, head work and pipe fine tuning jetting. Pro circuit r 304 shorty silencer 2stroke motosport. If you read the cr500 section on erics 2 stroke services. May 22, 2014 if i am unable to contact this gss race porting shop. Scavenging system redesign is more accurate, and doing so can entail complete overhauls of cylinder designs.
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. Computer design software is used to calculate the msv for head designs. Two stroke engine and exhaust design software north. There is one or more forwardlocated exhaust ports, two or more side transfer ports, and one rear intake port. We offer two stroke exhaust for all of the popular motorcycles and atvs. The old adage of stuffing cases on every project just isnt true any more. The platinum 2 pipe was made for people who ride or race offroad, and was built with strength and performance in mind. 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. Determine the level of porting you wish to achieve before you start cutting or grinding. I had the motor completely re built and has 2 hours on it. Porting calculator calculate the needed exhaust and transfer port durations to match the desired peak power rpm. Two cycle engine port timing calculator csgnetwork. We shall send you a pdf document with the templates for manufacturing your exhaust.
The basic design of the two stroke enginea and the book a. We offer twostroke exhaust for all of the popular motorcycles and atvs. 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. The most common mistake is to choose the wrong combination of engine components, making the engine run worse than stock. The software in addition to defining the geometry of the insert, it also indicates the processing steps for its craft realization. Heres how shaving off miniscule ammounts of metal can drastically improve your speed.
I have experience porting no power valve 2 strokes in the past im not a pro but have had strong results. Efficiency, velocity, trajectory all play a role, and there is no way to get this right without the proper porting tools. There are many places in which we can send our cylinder to and get it ported and polished. Hell take a competitors motor tune it to its best numbers on his dyno. Full 2 stroke rebuild time lapse 2007 yamaha yz125 win this dirt bike. Motocross action magazine motocross action magazine is the worlds leading publication about motocross and supercross.
Cylinder heads are made for porting, the more fuel and air you can get in, and the faster you can do it, the faster you will go. There are pipes and silencers for racing, recreation, quiet riding and even usfs approved spark arrestors. A myriad of different aftermarket accessories is available for you to custom tune your bike to better suit your needs. 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. To answer the last post early moto x bikes were aircooled. For a little background ive ridden a 1999, 2002, and 2003 cr250s with pc pipes and the the 02 and 03 had vforce reeds. 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. 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. Constructed from heavyduty 18gauge metal, it offers increased protection from rock or crash damage.
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