Remember Me. Over the past couple of years, the 2-stroke motorcycle has become increasingly popular again. Of course, wsp aecom rumors some this has always been the case. It is the cc to cc sized bikes that have seen a marked increase in second hand values. Hence, more people are now looking at restoring and tuning these bikes. As a result, we see a number of customers come to us asking for producing copies of the standard expansion chambers, or bespoke sizing and fabrication of one-off pipes for a specific tune of engine.
The most common request for bespoke pipes comes from the RDLC engine variants. While many try an existing set of pipes for these engine combinations, we've only seen limited success.
A far more effective approach is to use the engine specification to calculate the optimum dimensions for the exhaust chambers. We have now done many dozens of these, and the results have been exceptionally good.
After several attempts of trying use US sourced Quad pipes, he came to us to produce one-off pipes.
You can read more on that story here. Suffice it to say, that the results were good enough to get his bike banned from racing, and we now produce all his pipes for him.
This is the simplest of services as it consists of essentially copy what is already there, or fabricating and fitting a set of pipes to customer supplied specification. Costs will vary depending on the complexity of pipe runs, but usually are about:. We usually require to have the bike in our workshops for this service. This is next step up and is particularly suited to people who have a tuned engine where no existing pipes provide adequate performance. In order for us to undertake this service, we either measure the pertinent engine parameters ourselves, or supply a worksheet for the customer to take his own measurement.
This service is only supplied in conjunction with pipe fabrication as detailed above. This is the most comprehensive service we provide for extracting the maximum performance from tuned 2-stroke engines. It involves obtaining an extensive data set from an engine, mainly by hand measurements. It goes far beyond the sizing of expansion chambers and creates a model of the engine from airbox to silencer. The resulting outcome can be any of the following examples:. Innovation on 2 wheels.
Register Login Form. The spiritual successor to the RD Find out more.Discussion in ' 2 smokers ' started by ChillisJan 22, Log in or Join. Adventure Rider. Multicylinder 2 stroke into one expansion chamber? ChillisJan 22, Has this ever been done? Every performance exhaust for 2 stroke multi's has an expansion chamber for each cylinder. Just curious.
Tosh TogoJan 23, Joined: Nov 21, Oddometer: 1, ADV Sponsors. PistonPantsJan 23, Snowmobiles do it all the time. JonnyCashJan 23, I've seen 3 into 1 pipes offered for GT's. What I understand is that they run great, but give a strong midrange, not a top end hit. Joined: Apr 17, Oddometer: Location: S. Joined: Jun 18, Oddometer: 15, Location: the hills.
An associate will build these for RZ Yamahas. Freaky Deacon likes this. ChillisJan 23, I didn't think to look at the snowmobile market. That pipe above looks great! ShocktowerJan 23, Rediculous how on earth will your GF burn both calfs with out twin pipes BTW that is sexy looking. If anyone is interested I've asked Glyn the guy who built the pipe for permission to put some contact information up here. He does all sorts of engine work for road going 2 strokes. Joined: Feb 7, Oddometer: Location: where I am supposed to beOn a two-stroke enginean expansion chamber or tuned pipe is a tuned exhaust system used to enhance its power output by improving its volumetric efficiency.
Expansion chambers were invented and successfully manufactured by Limbach, a German engineer, into economize fuel in two stroke engines. Germany was running short of petrol, which was at that stage produced using coal and sewage transformation. An unexpected bonus was that the two stroke engines using tuned exhausts produced far more power than if running with a normal silencer. After the end of the second world war, some time passed before the concept was re-developed by East German Walter Kaaden during the Cold War.
He later passed his knowledge to Japan's Suzuki. The high pressure gas exiting the cylinder initially flows in the form of a " wavefront " as all disturbances in fluids do. The exhaust gas pushes its way into the pipe which is already occupied by gas from previous cycles, pushing that gas ahead and causing a wave front. Once the gas flow stops, the wave continues, passing the energy to the next gas down stream and so on to the end of the pipe.
If this wave encounters any change in cross section or temperature it will reflect a portion of its strength in the opposite direction to its travel. For example, a strong acoustic wave encountering an increase in area will reflect a weaker acoustic wave in the opposite direction. A strong acoustic wave encountering a decrease in area will reflect a strong acoustic wave in the opposite direction.
The basic principle is described in wave dynamics. An expansion chamber makes use of this phenomenon by varying its diameter cross section and length to cause these reflections to arrive back at the cylinder at the desired time in the cycle. This section of the system is called the "header pipe" the exhaust port length is considered part of the header pipe for measurement purposes. By keeping the header pipe diameter near constant, the energy in the wave is preserved because there is no expansion needed until later in the cycle.
The flow leaving the cylinder during most of the blowdown process is sonic or supersonic, and therefore no wave could travel back into the cylinder against that flow. Once the exhaust pressure has fallen to near-atmospheric level, the piston uncovers the transfer ports. At this point energy from the expansion chamber can be used to aid the flow of fresh mixture into the cylinder. To do this, the expansion chamber is increased in diameter so that the out-going acoustic wave created by the combustion process creates a reflected vacuum negative pressure wave that returns to the cylinder.
This part of the chamber is called the divergent or diffuser section and it diverges at 7 to 9 degrees. It may be made up of more than one diverging cone depending on requirements. This effect is mitigated by the port-blocking wave.
When the transfer is complete, the piston is on the compression stroke but the exhaust port is still open, an unavoidable problem with the two stroke piston port design.
To help prevent the piston pushing fresh mixture out the open exhaust port the strong acoustic wave produced by the combustion from the expansion chamber is timed to arrive during the beginning of the compression stroke. The port blocking wave is created by reducing the diameter of the chamber.
This is called the convergent section or baffle cone. The outgoing acoustic wave hits the narrowing convergent section and reflects back a strong series of acoustic pulses to the cylinder. They arrive in time to block the exhaust port, still open during the beginning of the compression stroke and push back into the cylinder any fresh mixture drawn out into the header of the expansion chamber.
The convergent section is made to converge at 16 to 25 degrees, depending on requirements. The stinger's length and inside diameter are based on 0.Same goes for the companies that offer exhaust systems. There are at least a dozen that have been in business for a very long time, and they offer a wide variety of products fitting both modern bikes and vintage models.
The Pro Circuit Works Pipe is a performance-oriented expansion chamber developed with direct ties to factory race teams and an in-house dyno team. Pro Circuit hand-welds and then pounds the seams on every works pipe to target both increased torque and additional power. The Works pipe features an unplated, oiled metal finish for its most popular two-stroke exhaust system. It features reinforced mounting brackets for durability and offers unparalleled performance and power for every two-stroke application.
Increased horsepower and torque gains will quickly be noticed across the entire rpm range. The unplated, oiled metal finish requires some maintenance but really gives your bike that works look. Devoid of paint or any platingthe Factory Fatty is shaped after hours of dyno time and field testing with racing teams. It is then molded into an exhaust system that both broadens the power and gives the power the character that each individual machine demands.
Each system features hand-pounded seams for smooth flow transitions. The nickel-plated finish enhances durability, and it can be used with an FMF or stock silencer. The FMF Gnarly pipe is designed for the off-roader looking for a tough system. It improves the power curve where the rider needs it, offering a stronger flow of bottom power.
The Platinum pipe is equipped with the same performance gains as the Works pipe but targets riding in extreme weather conditions. It is constructed of AKDQ high-quality carbon steel and includes a nickel-plated finish to reduce pipe maintenance and to help protect the chamber against the elements. The Platinum pipe also features hand-welded and pounded seams and reinforced mounting brackets and stingers for increased durability.
The Platinum 2 pipe is platinum-plated to protect it and has been designed to offer a stronger power gain in the low to midrange, where the off-roader needs increased tractability. They target broad useable power with their Pro-Flo chamber. Nickel-plated and equipped with a thicker skin, the Armored Enduro exhaust is strong and fights to ward off the hits and smashes that occur when riding off-road.
It has a CNC-machined manifold, power gains over stock and has been tested on the World Enduro circuit. The Scalvini expansion is a true cone pipe that can trace its DNA back to the works pipes used by factory two-strokes and is built in Italy.
Scalvini hand-builds each pipe to mirror the bottom performance of stock with a harder mid hit and a stronger pull on top.
Each system comes with an ID tag and features a CNC-machined exhaust flange and double-wall mounting brackets for strength. The MX2 Cone Look pipe is a stamped unit with welding lines added that are reminiscent of the old works pipes.
Its MX2 Works pipe is made from gauge carbon steel, features broad-based power gains, is hand-welded for a proper fit, and is made in the USA. The goal is tractable and usable power, and the deep stamping process was developed on the tough European circuits where controllable power is key.
DG specializes in vintage, Evo and Revo two-stroke exhaust systems. DG pipe work with the stock hardware and silencer, although DG also manufactures silencers.
Motorcycle Exhausts - 2-Stroke Expansion Chambers
The pipes come in a raw finish with a removable anti corrosion coating. Contact: dgperformance. You might also like More from author. Home Page Carousel.Discussion in ' The Garage ' started by Sucks2driveFeb 20, Log in or Join.
Adventure Rider. Removing dents on a 2 stroke expansion chamber Discussion in ' The Garage ' started by Sucks2driveFeb 20, Sucks2driveFeb 20, Please forgive me if this is I came across this on a site somewhere a couple of years ago, it works brilliantly!expansion chamber building,two stroke tuning,pipes
If you have a 2 stroke with the large expansion chamber sometimes they get a big fat dent in them and look fugly. The next morning, the dent should have miraculously disappeared. The ice forming presses out and 'pops' the dent.
To remove the Ice, let it thaw naturally or use a blowlamp, or put it in a warm place to thaw. I have also used the same method to remove dents from oil tanks, gas tanks and even an old brass paraffin stove.
Back in the day, we used air pressure for popping out dents in pipes and gas tanks. ADV Sponsors. WooPigFeb 20, The most important thing is to not let the wife find it in the freezer. Keep that in mind when cleaning freshly honed cylinders in the dishwasher and air filters in the laundry too. But yes, I've also used the ice technique with pretty good success.
Highly recommended. If it doesn't work, there are always ads in the back of the dirt bike magazines for pipe repairs. BDR1Feb 20, Lone RiderFeb 21, Joined: Jan 29, Oddometer: 25, Location: out and about. I think getting the pipe hot - running the bike - and then holding ice to the offending dent has worked for some. Joined: Apr 16, Oddometer: 1, Location: chicagoland.
That really works reliably? I got a typical saddle type gas tank cap.
Norick Abe YZR-500 Replica
Trident '95 with a nice crease in the side.Two stroke engines fascinate me. They are so simple and fun that I've always enjoyed tinkering with them. There are many ways to boost the power, one of which is by installing a "tuned" pipe. The way a two stroke motor works causes them to be fairly noisy and a bit inefficient. A tuned pipe has a set of cones- Divergent meaning the cone gets bigger and Convergent meaning the cone gets smaller that are built to cause "echoes" or pressure waves to reflect back, which if done properly can increase the power of the engine.
Check out this link, it will make a little more sense. That's a very loose explanation, but there you go. I've always wanted to build an expansion chamber This is where P. This Piece Of Junk was and is my first motorcycle Somehow, this one snuck home. I dug it out of storage a few years ago and began this process, so follow along as I make mistakes and learn a thing or two about building your own expansion chamber!
Please note, this is NOT the only way to do this. I think there is an easier way- done by cutting out two sheets in the correct shape, welding the edges, and the pumping ultra high pressure water in to "expand" the pipe, but I didn't have the tools at the time to do it like that. This is just how I did it This is NOT an easy quick project. It requires a lot of big, expensive tools. I'm lucky enough to have access to a shop that has everything I needed. There are alternate ways to make pipes, which I will discuss at the end of this instructable.
You never know! Tools: -Safety equipment- safety glasses, ear plugs, gloves, etc. Great program. I tried a few free ones, but the first attempt at making a pipe from those didnt work so well In my case, that was advrider.
I'm not going to go into great detail, but you can't just build a pipe and throw it on there expecting it to work well. You have to know a lot of things about your engine- port size and location, port timing, desired application, etc.
You will have to figure out all of this information. Here is a VERY basic rundown of what you need to do: Before you can start at all, you have to know your port timing. Port timing is measured in degrees. Remove the engine side cover over the flywheel.
Set the engine at Top Dead Center TDC - meaning the piston is all the way to the top of the cylinder as far as it will go. Attach the Degree Wheel to the flywheel, and align it with something on the engine or use a laser like I did. See Picture 1.Since '02 xBhp is different things to different people. From a close knit national community of bikers to India's only motorcycling lifestyle magazine and a place to make like-minded biker friends.
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Forgot your password. Remember Me? Page 1 of 4 1 2 3 4 Last Jump to page: Results 1 to 10 of Thread: How to make your own Expansion Chamber! How to make your own Expansion Chamber! Once again before I start Its really good information. Piston just passed top of exhaust-port. A strong pressure wave sucks out burnt gases from cylinder. Fresh mixture has now filled the cylinder, and the exhaust sucks out even more fresh mixture. Thanks to this, the cc cylinder gets as much cc fresh mixture sucked out of the crankcase.
The pressure wave has now been reflected at the end of the chamber, and perfectly timed pushes all fresh mixture back into the cylinder just as the piston closes the exhaust-port.
The Design To start with, you need a good design of the chambers you are about to make. This is, as I see it, the absolutely most important thing to get a good result. What a good design is, depends on what kind of power you want, what tune the rest of the engine have, etc. It's many factors that decides how the chambers should be designed, for example carbs, transfer ports shape and height, exhaustport shape and height and more. If you for example raises the exhaustport, you will move the powerband to higher rpm's, and by lengthening the chambers you will move the powerband to lower rpm's.
So what's the difference between a good and a bad chamber. Simplified the good chamber works as described in the figures above giving lots of power over a wide rpm-range.
The bad designed chamber have a weak pressure wave that don't suck the charge out of the cylinder, and then don't push much fresh charge back into the cylinder, producing less horsepower, wasteing fuel and polluting more. With this change, most standard aftermarket chambers design don't work so well anymore. What you need now is a chamber design that fits your specific tuned engine. Here you can see some examples of possible chamber designs: As you can see, they differ quite a lot from each other.
But on a race tuned RZ they would both work much better than the original RZ pipes. One last thing regarding design, computer software can help you with the design, but don't expect superdesign from the software. The software uses mathematical formulas that are approximations of reality, and the software made for home-computers uses even more simplified formulas because good simulation of expansion chambers requires much more computer-power than you home-PC can offer.
Start working The first thing you need to do is buy some steel I don't recommend using stainless steel, because it cracks more easily. I think 0,7 mm thick sheet-metal is a good choice. It is light and strong enough.