Rotary valve two stroke tuning book

Kawasaki and others have also used rotary valves in twostroke motorcycle engines. A rotary valve is a type of valve in which the rotation of a passage or passages in a transverse. I would refer you to rotary engines of ww1 by william morse. Rotary exhaust valve for twostroke engine industrial. As far as my experience goes, i would modify the rotary valve for longer inlet duration, a reasonable starting point would be finished closing not later than 60 degrees atdc, starting opening 120.

An excellent academic book on the theory behind performance tuning for 2stroke motorcycles. I will only use two studs because i want the plate to be able to pivot between the valves to allow for uneven wear in them. Pdf a new rotary valve for 2stroke engines enabling. There are only 3 moving parts in the engines top end. A stroke is the action of a piston travelling the full length of its cylinder. The inlet port opens 30 after bdc and closes 79 after tdc. Why isnt the rotary valve twostroke used by anybody still. This will mount using studs in the two 38 holes in the head.

If youve ever thought about futzing with the port timing of your scooters one cylinder engine or making your own performance exhaust for your dirtbike or tuning the carb on your go kart, this book is for you. 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. Twostroke performance tuning in theory and practice. Twostroke engines and patrova in this case 2stroke, the rotary valve has only one kind of ports either intake or exhaust and rotates in synchronization with the crankshaft 1. Everyday low prices and free delivery on eligible orders. You could have a 2stroke rotary, or a 4stroke rotary, just like you can have a 2stroke piston engine, or a 4stroke piston engine. Changing the pitch of brass instruments controlling the steam and exhaust ports of steam engines. Kawasaki bighorn 350 street fighter road racer buildup. It is the same simplicity in design, however, that causes a two stroke engine to be less fuelefficient and produce high specific levels of undesirable exhaust gas emissions. I first became interested in the rotary valve as applied to internal combustion engines around about 1939, after reading an article in a motor cycle magazine describing an aspin rotary valve four stroke engine. Reed valve news newspapers books scholar jstor october 2014 learn how and when to remove this template message.

To seal the valves to the head, the hubs will be grooved for a piston ring seal in the head. Contents chapter 1 introduction 9 chapter 2 the cylinder. Why isnt the rotary valve twostroke used by anybody. Lovitt, westholme, wells street, messingham, scunthorpe, lincs. Stroke 3 suck as there was no inlet valve as such, the exhaust valve took over that function staying open until 120 degrees after odc this allowed supplementary fresh air to enter the cylinder backwards. The common stopcock is the simplest form of rotary valve. It is my hope that this book will assist the enthusiast involved in motocross, enduro, desert, road or gokart racing to develop and tune his twostroke engine. Mar 04, 2012 with the use of intake valves either reed or rotary the crankcase can be sealed when the charge has been sucked in, then the descending piston compresses the charge so that as the intake port opens more fuel flows into the combustion chamber. However in spite of some very innovative designs being incorporated in twostroke engines they. Two stroke intake types reed valve, rotary valve, piston. Lets all get together and start a two stroke tuning thread that rivals others in the world, as, we are all kiwis, and as such have an amazing pedagree particularly when it comes to high powered racing two stroke.

All areas of engine operation are explained and analysed, from air and fuel, through carburation, ignition, cylinders, porting, reed and rotary valves and exhaust systems to cooling and lubrication. Rotary, 2 stroke and 4 stroke engine yahoo answers. In a twostroke engine, having a block, including a cylinder, a cylinder head, a piston, a crank, a crankcase, an inlet air passage, an exhaust port and an exhaust passage, a rotary exhaust valve installed in the vicinity of the exhaust port, said rotary exhaust valve including a through valve passage constituting a chamber, said rotary exhaust valve being operable. The piston crown opens and closes the exhaust and transfer ports. With the use of intake valves either reed or rotary the crankcase can be sealed when the charge has been sucked in, then the descending piston compresses the charge so that as the intake port opens more fuel flows into the combustion chamber. This twostroke engine was of the uniflow type, with exhaust ports uncovered as the piston moves down. In contrast, a twostroke engines valve timing may be altered simply by reshaping the holes in its cylinders, and its power output markedly changed by utilizing inertia and resonant effects in its intake and exhaust tracts. Ecu simon performance technology 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. The main technical issue that has been addressed is the design of a practical rotary valve seal. Wont be long until the nitro powered homemade rotary valve peugeot spx is up and running again. A modern two stroke thus effectively has two compression ratios.

In the day, a few brave souls raced the 350 bighorn in motocross and desert racing with occasional success, but in generalit was a horrible off road motorcycle. I like to tinker with engines, and the complexities of the poppetvalve fourstroke make modifications very expensive. The port heights, widths, areas, directions they flow, and relationships to one another all have a significant influence on how the engine will behave. The vespa p200 engine is a good example of a by the book rotary valve two stroke. A rotary engine must have an effective air filter at all times. Turbo and even supercharger setups of various configurations can be very useful, however, they are often more complicated with 2 stroke tuning than with 4 stroke applications on a tangent, i did witness a 50cc turbo 2 stroke bike that would do over 150mph, but i digress. Reed valves are a type of check valve which restrict the flow of fluids to a single direction. On the other hand, while the twostroke engine does not commonly require large. Directing the intake up over the crank and modifying the valve. Homemade 4 stroke engine with rotary valve duration.

Process for efficiency improvement of a 2stroke engine with rotary valve on the exhaust, portuguese patent n. A quick explanation of the three most common 2 stroke intake types. Graham bell is an acknowledged expert on engine tuning, with many years experience in this field. A twostroke cylinder consists of exhaust, transfer, and occasionally inlet.

As stated above, the exhaust valve stayed open during the whole of this stroke, by which time all the residual gasses were discharged. A new rotary valve for 2stroke engines enabling overexpansion. Rotary valve for a twostroke engine 9th june 1944 the. Bells fourstroke performance tuning book, this book goes into extreme detail regarding performance tuning a twostroke engine.

I usually recommend this book along with gordon jennings two stroke tuners handbook, because this book has what the first one doesnt and vice versa. Most of these bikes are no longer with us, but this does give you a chance to study some of the nifty ways to really lube up a two stoke engine. One of the leading causes of power valves failing is the lack of proper maintenance on the components. Scott also developed a rotary valve engine in 1912, winning the senior tt in that year and the following year. Overview the kawasaki 350 bighorn is a rotaryvalve 350cc 2stroke single enduro aka dual purpose bike built from 1970 to 1975. The two stroke rotary diesel engine 1999012888 an innovative rotary engine uses a rotor that executes pendulumlike oscillatory rotation. Nov, 2017 a quick explanation of the three most common 2 stroke intake types. Jun 26, 2009 a rotary engine and a 2 or 4 stroke engine are independent concepts.

Uniblock cylinder e the cylinder has a uniblock design with. The twostroke that we know of today was invented by an english man by the name of joseph day who was born in london in 1855, in 187374 he trained as an engineer at the school of practical engineering at crystal palace in london. The shaft goes up to head level where it has a 12 pitch 18 tooth pinion that drives the two 36 tooth valve gears which will be machined into rotary valves, one for intake and the other for exhaust. The two stroke that we know of today was invented by an english man by the name of joseph day who was born in london in 1855, in 187374 he trained as an engineer at the school of practical engineering at crystal palace in london. There used to be an outstanding book on 2 stroke tuning. It covers history, physics, engineering and practicum for the development and refinement of high performance two stroke engines. In a twostroke engine, one of the two strokes combines the intake stroke and the compression stroke, while the other stroke combines the combustion stroke and the exhaust stroke as the piston travels upward in the cylinder, it creates low pressure area in the crankcase. On older engines, a rotary valve or the piston may also be used to control. Reed valves in twostroke engines have been placed in the intake ports and. One may think that a change in valve timing would do wonders for a fourstrokes power. The late gordon jennings, who did so much to make twostroke tuning understandable twostroke tuners handbook, 1973, 156 pp, set himself the task of. Unless you have a deep passion for twostroke tuning, are willing to spend.

Two stroke engines and patrova in this case 2 stroke, the rotary valve has only one kind of ports either intake or exhaust and rotates in synchronization with the crankshaft 1. Most rotary valves to my knowledge are the disc time like they have on gocart engines, but this one uses one of the crankshaft flyweights as the disc. 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. Then in 1906 the french garard motor appeared with a rotary disc inlet valve. The intake tract and valve are discussed in the 2 stroke tuning book, i was thinking of doing those modifications.

Exploring twostroke motorcycle engine design cycle world. Rotary valve engines operate on the same loop scavenge principle, but in this case. My own interest in the two stroke, which had reached the level of an obsession by 1963, was generated by comparative poverty. The rcv seal design provides a gastight compression seal, accommodates large thermal distortions, and takes up both production tolerance and longer. One may think that a change in valve timing would do wonders for a four stroke s power. Fully revised this book takes the reader through the various modifications that can be made to a twostroke engine and its components to give maximum useable power output and mechanical reliability. You get lots of fors and againsts, between rotary disc valve advocates, and reed valve advocates. I dont know the companys anme, and havent even seen anything like this lately. Lets journey back to 1973 and read the book that was the two stroke bible of that era. Bells four stroke performance tuning book, this book goes into extreme detail regarding performance tuning a two stroke engine.

Rotary valves have been applied in numerous applications, including. You could have a 2 stroke rotary, or a 4 stroke rotary, just like you can have a 2 stroke piston engine, or a 4 stroke piston engine. The advantage of a rotary engine is a small number of. A rotary valve is a type of valve in which the rotation of a passage or passages in a transverse plug regulates the flow of liquid or gas through the attached pipes. For general theory and tips regarding tuning and rebuilding two strokes, i would strongly recommend two stroke performance tuning by a.

After centering the rotary table, i mounted the gear valve so. A twostroke cylinder consists of exhaust, transfer, and occasionally inlet ports true inlet ports are only found on piston or rotary valve controlled engines. Dec 06, 2017 the cylinder is close to ready, and almost all parts are either here or in the mail. Post pics of the two valves laying on top of one another if they are different. For general theory and tips regarding tuning and rebuilding twostrokes, i would strongly recommend two stroke performance tuning by a. The morbidelli 125 twin road racer is a rotary valve engine. Everything you need to know about the twostroke cylinder. The advantage of a rotary engine is a small number of moving parts, and a high powertoweight ratio. 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. Stroke 1 bang the engine fired 18 degrees before odc outer dead centre. Ke100, trying to mimic the greenstreak kawasaki 2 stroke. We recommend feeding the box with two fourinch diameter hoses or one sixinch diameter hose. Reed valve, rotary valve and piston controlled induction piston port. The only moving parts inside simple two stroke engines are the crankshaft, the connecting rod, and the piston.

At the bottom of the power stroke, the transfer ports, which. In a two stroke engine, having a block, including a cylinder, a cylinder head, a piston, a crank, a crankcase, an inlet air passage, an exhaust port and an exhaust passage, a rotary exhaust valve installed in the vicinity of the exhaust port, said rotary exhaust valve including a through valve passage constituting a chamber, said rotary exhaust valve being operable. At the time, i had a 175cc bridgestone dual twin, another rotaryvalve twostroke twin, with a funky 4 and 5speed gearbox. Generally, with the last of the modern era road race 2t engines, the reed valved engines, tended to produce more low mid range, as against the disc. Rotary valve, can someone explain kawasaki 2 stroke. A welldesigned cold air box with ram air intake can add 3 mph to a cars top speed. Other books to his credit are modern engine tuning, twostroke performance tuning and forced induction performance tuning. The cylinder is close to ready, and almost all parts are either here or in the mail. The twostroke rotary diesel engine sae international. Reed valve v rotary disc intake and why small 2 stroke engines. One time, i stretched my 120pound frame lengthwise, putting my feet on the luggage rack, chin on the tank, and my hands on the fork tubes there was a thumbscrew throttle lock. My own interest in the twostroke, which had reached the level of an obsession by 1963, was generated by comparative poverty.

This necessity is also true of cold air boxram air intake systems. This rotary valve serves the cylinder as the engine cycles through the conventional 4 stroke cycle. I didnt plan on getting this carried away, after all, its basicly oil in the gas. At the time, i had a 175cc bridgestone dual twin, another rotary valve two stroke twin, with a funky 4 and 5speed gearbox.

It would be nice to move this in to the mainstream section of this site, and i hope we can do this shortly, however, good things take time, and some cooperation is needed. Therefore, its essential you know what some of the major causes are for power valve malfunction and damage. Jun 09, 2008 2 reed valve inducted two stroke doesnt get any simpler than that with exhaust power valve. A rotary engine and a 2 or 4stroke engine are independent concepts. Because there is no dedicated exhaust stroke, scavenge air is blown in to clear the exhaust gases out of the cylinder by an external compressor, and then the fuelair mixture is admitted. Wont be long until the nitro powered homemade rotary valve. The twostroke power valve is still susceptible to damage. However in spite of some very innovative designs being incorporated in two stroke engines they.

I like to tinker with engines, and the complexities of the poppet valve four stroke make modifications very expensive. Data as bore, stroke, rod length will only be necessary to enter once if you not quit, they will be carried along in every program part. The rotary valve has only one slot for the timing of intake and exhaust and is simple and cheap to produce. The twostroke rotary diesel engine 1999012888 an innovative rotary engine uses a rotor that executes pendulumlike oscillatory rotation. Development of a rotary valve small fourstroke engine. Disc valve engines can have much more focused inlet timings than reed piston port engines. I have the book, but its nice to have as a pdf as well and a good reference for those who dont know about it. This is converted into uniform rotation of the drive shaft by a simple mechanism.