2 stroke porting secrets

Ive started porting the peugeot spx iame m50 and thought id share a few more tips for how to go about porting two stroke cylinders. My very first successful porting job was achieved because i actually took over a week just studying the piston and cylinder, and the flow through the engine. Best cylinder porting, engine porting, 2stroke porting, 4. If you are aiming for these qualities, modifying your 2stroke engine is a great strategy. We use computer design software to maximize power and torque at any elevation. Porting and polishing twostroke motorcycle engines motorcyclist. We are known to use huge amounts of epoxy to redesign transfer tunnels to make power where the competition wont. Secret 2stroke engine power is the primary and secondary compression settings in the machine. This led to the development of a 125 single employing a porting arrangement originally invented for two stroke diesels by german engineer dr. The compression ratio is the ratio of all the space above the piston when it is at the bottom of the stroke compared to all the space above it at the top of the stroke. Dr has done extensive testing over the last 40 years to continually offer industry leading port modifications for most sport atv models and mx motorcycles. We believe that using this software will help your 2.

Oct 04, 2011 changing the power of 2 stroke engine 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. Bigger carburetors, higher compression ratios, altered port timings and expansion. Everything you need to know about the twostroke cylinder. You should only rely on the experience of the very best. Assign fixed relationships between transfers and exhaust port. Bimotion 2 stroke software has been commercially available and in professional use since 1991. Ive become interested in 2 stroke port timing lately and im curious what some of the saw builders here use for their figures. The exhaust port opens and combustion gas starts down the pipe at supersonic speeds.

How exhaust port timing affects two stroke performance. Porting and polishing two stroke motorcycle engines. Porting and polishing twostroke motorcycle engines. Software contains ed material, trade secrets, and other proprietary material, and in order to protect them you may not decompile, reverse engineer, disassemble or otherwise reduce the motion software, inc. 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. It seems that there are some pretty standard cookbook numbers that most people start out with based on application and what other things have been done to the motor, like higher compression, pipes, reeds, etc. The other is how air density barometric pressure, temp, humidity, and elevation change, affects horsepower. Brent at tdc 2 stroke has acquired data from from builders all over the world. What you have accomplished up to this point will definitely allow your engine to run smoother, stronger, and more efficient. Unlocking the secrets of 2 stroke porting, part 2 how to trace and. Scavenging system redesign is more accurate, and doing so can entail complete overhauls of cylinder designs. For port work, one company that will help you is 2strokeporting.

Schnurle porting loop porting schnuele porting refers to a type of cylinder port arrangement that aims the scavenging flows to loop through the cylinder and combustion chamber to help push the spent gasses exhaust out the exhaust port. The morbidelli 125 twin road racer is a rotary valve engine. A two stroke cylinder consists of exhaust, transfer, and occasionally inlet ports true inlet ports are only found on piston or rotary valve controlled engines. Simplest way to measure exhaust port timing on a two stroke engine.

Port timing basics airgasoline enters the engine from the carburetor at a ratio close to 15. Crankcase and cylinder porting is probably the most controversial subject among performance 2 stroke engine builders. Conventional two stroke engine has number of advantages over four stroke engines 2. However, you shouldnt just pick any business that you can find anywhere. An engines thermal efficiency, that is, the efficiency with which it can turn heat energy into mechanical energy, is directly related to the compression ratio.

How a 2stroke works your 2stroke motor is an air pump. 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. Performance porting of vintage 2strokes vintage dirt bikes. Part of the problem is understanding the pulse or charge nature of the airflow in a 2stroke engine. A dremel is for wood working or engraving your favorite paper weight, but not for porting and polishing on a 2 stroke. This page was created to educate others on the benefits of two stroke porting. When porting begin to open and closed in crankshaft degrees duration, we will undoubtedly be modifications on the right path. Crankcase and cylinder porting is probably the most controversial subject among performance 2stroke engine builders.

Pdf improving the performance of twostroke motorcycle with. He then has put his own programs together and applied to us mx 2 stroke motors. The porting arrangement of any 2 stroke engine will greatly effect all 3 of the things listed above. The kit includes flex shaft srmc porting motor and speed control, 1082amc right angle rotary tool for transfer ports, 44mc straight rotary tool, and 2 tungsten carbide burrs. I only have a dremel and was wondering if i could do anything at all myself to my yz125 before i put it together. If your looking for a big bore, porting, or a complete motor build we have you covered. The most common mistake is to choose the wrong combination of engine components, making the engine run worse than stock. 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. I have had a large number of 2 stroke cylinders ported, and a fair number like 200 4 stroke cylinder heads ported generally from race cars. Trying to port a late model cr250 with information on the macdizzy site will be impossible. Part of the problem is understanding the pulse or charge nature of the airflow in a 2 stroke engine.

Since modifying the 2 stroke engines require not only a big budget in funding but also modification strategies. Start your service order now with our service order form. 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 port opening to the cylinder. This is a 2 stroke porting and polishing kit designed for 2 stroke cylinders in the 150 cc to 35 cc range. But, they suffer from low scavenging and trapping efficiencies which lead to poor performance and high exhaust. Unlocking the secrets of 2 stroke porting, part 2 how to trace and measure ports. Quot you may end up with the bridge between the main port and the sub ports may crack if you open the subs wider.

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. Unlocking the secrets of 2 stroke porting part 1 why do you map. I have found that there is some very reliable information on 2 stroke porting available at macdizzy. The 15sr kit is suitable for 30cc and larger 2 stroke cylinders. Cc specialty tools porting and polishing equipment. Hopup tips the following hop up tips are for reference only. There are 2 major types of 2 stroke engines, schnurle and cross flow. Determine the level of porting you wish to achieve before you start cutting or grinding. As of 2005 rk tek is porting cylinders using cnc vertical machining centers cnc porting. 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 piston crown opens and closes the exhaust and transfer ports. With a very versatile selection of tools, the 1082sr kit can also be used to modify 2 strokes above 150 cc and 2 strokes as small as 30 cc of displacement. Advance porting basics pocket bike forum mini bikes. Our goal is to achieve the biggest power gains as possible, while maintaining reliability on your 2 stroke engine.

The port heights, widths, areas, directions they flow, and relationships to one another all have a significant influence on how the engine will behave. By combining designs which degner brought from mz with japanese technology in. Unlocking the secrets of 2 stroke expansion chamber exhausts e1 duration. Ted boyko began porting cylinders 45 years ago, when the twostroke craze was at its peak, and hes still at it today. We are known to use huge amounts of epoxy to redesign transfer tunnels to make power where the. Having the mix flow to the proper areas and not to other areas contributes greatly to how much fuel is required and dictates the internal engine temperatures. These two links are a great guide, and will help you and your understanding of porting and polishing. Contents chapter 1 introduction 9 chapter 2 the cylinder. Trx7 mxwoods low end the esr trx7 cylinder is our lowend power option. You should read about how the two stroke enigne works before you. It was this concept which ultimately brought success to the two stroke, both as an economical power source for transport and as a powerful, lightweight power source for competition.

Many things will affect the power delivery of twostroke motorcycle engines. 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. Heres how shaving off miniscule ammounts of metal can drastically improve your speed. We were the first to provide insight to trade secrets on you tube and many popular social forums on the internet. The large majority of expensive work has been poor quality, with little attention to detail. At first, the kx500 looked fun, interesting, and all that, but im now under the impression that the stock transmission ratios would make gearing a pain no alternative gears available, as far as i can tell and that the increased displacement is offset by a. Two stroke porting is all about understanding timearea requirements for an engine and understanding how port discharge rates and direction interact with the piston shape and cylinder head to assist scavenging. More than all the other popular hopup shops combined. The next link will go over some basic principles behind the goal of porting and polishing.

Tips on how to port a two stroke cylinder, what to donot do and how to do it right. Simple twostroke cylinder porting tutorial youtube. I have over 38 years experience working with some of the best 2 stroke engineers in the world. This is why we often suggest the rat rider if you want to send the machine to work on all engines or motors should be packaged and gentlemen, because not enough just to modify the block or head only. Nov 20, 2010 some porting guys think this is dumb but really cant say why, others say its a good in theory setup. Engine type 2 stroke, carb urettor, aircooled, singlecyli nder. 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.

Two stroke cylinder porting tips watch this before you. Two stroke motors are more efficient that four strokes for a few reasons. 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. Kpmotosolutions are primarily two stroke raceroad and motocross tuning specialists with over 30yrs of experience modifying building and repairing two strokes whether its a moped or a gp bike if its fitted with a two stroke engine we can sort it for you. If you are aiming for these qualities, modifying your 2stroke engine is. Unlocking the secrets of 2 stroke porting part 1 why do you map the ports to. Performance porting of vintage 2strokes vintage dirt. A myriad of different aftermarket accessories is available for you to custom tune your bike to better suit your needs.

With my porting, head modifications, and pipe i am able to make 110. 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. Purchase the porting tools you need at our online store. Cylinder porting the cylinder ports are designed to produce a certain power characteristic over a fairly narrow rpm band. Many two stroke porting jobs will include some piston skirt removal, lowering of the intake port and deburing. When tuning 2 stroke engines raising the exhaust port is common practice. Files are great for busting out of prison or maybe a gal to do her nails, but not for professional porting of any kind. This is the second of a series of videos on the topic of 2 stroke engine ports that you need to know if you are intending to modify your engine. To me, and maybe just to me, the greatest motocross bike ever made is the 20062015 yamaha yz250 two stroke after that they got a little long in the tooth, but are still very good bikes. This first link will discuss terms and the 2 stroke cycle. 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. The inlet port opens 30 after bdc and closes 79 after tdc. Dr has done extensive testing over the last 40 years to continually offer industry leading port modifications for most sport atv.

Pipes, silencers, carburetors, reeds and valves are all popular bolton modifications. Though engines try to do this process naturally, a ported 2stroke. This is the first of a series of videos on the topic of 2 stroke engine ports that you need to know if you are intending to modify your engine. Calculates port heights from durations, or durations from port heights. Eric gorr does all the porting himself and has worked with porting tools since the early 1970s and ported over 50,000 cylinders. Chapter 2 the cylinder head chapter 3 porting and cylinder scavenging 27 chapter 4 the exhaust 76 chapter 5 carburation 93 chapter 6 ignition 125 chapter 7 the bottom end 143 chapter 8 lubrication and cooling 166 chapter 9 power measurement and gearing 174 appendix i introduction 187 a motocross modifications 187. Not all porting is the same even the word porting has been mis used over the years. I used a sharpie marker to make reference marks, measured the port windows, the port timing, etc. Our porting leads the way in performance and technology.

Kpmotosolutions are primarily two stroke raceroad and motocross tuning specialists with over 30yrs of experience modifying building and repairing two strokes whether its a moped or a gp bike if its fitted with a two stroke engine we can sort it. Eric gorr racing offers allinclusive porting packages for all types of 2 stroke and 4 stroke engines used in dirt bikes, atvs, snowmobiles, and shifter karts. This is the third of a series of videos on the topic of 2 stroke engine ports. Of course if your exact engine and performance needs are not featured in one of the sites, your are on your own. Many things will affect the power delivery of two stroke motorcycle engines. The cylinder pressure drops, and the fresh charge transfers thru the transfer ports, over the top of the piston, and out the. Porting your 2stroke motorized bicycle engine duration. These modifications can be extremely effective when used in the right combinations. Thats over a 50% increase in horsepower and 11 ftlbs more torque. After all of this is done, you have successfully matched your engines ports. Porting secrets that make more power honda trx 450r.

How to port and polish a 2stroke engine bikeberry blog. How to tips from tj on porting and polishing 2 strokes. This is a pretty good discussion from a long time customer, eric gore at forward motion. Porting the cylinder designed by engineers to create energy in a certain rpm range resulting in engine character of its own. Pdf improving the performance of twostroke motorcycle. Basic 2 stroke tuning changing the power band of your dirt bike engine is simple when you know the basics. 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. Diy moto fix website for fixing rebuilding repairing your. This is another reason why some big bores require less fuel than others. Porting and polishing your 2stroke engine is a great way to boost its power. Airgasoline enters the engine from the carburetor at a ratio close to 15. Oct 17, 2017 two stroke cylinder porting tips watch this before you start cutting. Has any one done any kind of porting or polishing to a 2 stroke cylinder themselves. Hell take a competitors motor tune it to its best numbers on his dyno.