2 stroke engine performance tuning

tag:blogger.com,1999:blog-7824277497564566712011-11-28T06:15:29.444+07:002 stroke engine performance tuning2 stroke engine performance tuning Copyright © 1973 by Gordon JenningsFuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.comBlogger461100tag:blogger.com,1999:blog-782427749756456671.post-11589683919291559532008-01-27T18:35:00.000+07:002008-01-27T18:38:40.870+07:00expansion chamber (5)

Here, our original wave reaches that “cure”. Following the diffuser, and after perhaps a couple of inches of straight-walled chamber, the wave encounters a converging cone that effectively constitutes a closed end to the expansion chamber. A part of the wave energy will already have been inverted by the diffuser and sent back to the cylinder, but there is enough of its original strength left to

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-62908328061755214402008-01-27T18:31:00.000+07:002008-01-27T18:35:02.224+07:00expansion chamber (4)

Years ago, the exhaust system ended right behind the diffuser. That was the arrangement on the old supercharged DKWs, and we saw stub megaphones used on the Greeves scramblers of the fairly recent past. Those devices did a job in clearing exhaust gases from the cylinder, and helped the fresh charge up from their crankcase, but their vacuuming effect was very much a mixed blessing: their problem

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-50773019394222917882008-01-27T18:17:00.000+07:002008-01-27T18:31:01.297+07:00expansion chamber (3)

THE BASIC PROCESSWhen the exhaust port cracks open, gases still under a considerable pressure burst out into the exhaust tract, forming a wave front that moves away at high speed down the port and headed for less confined quarters. After traveling a comparatively short distance, this wave reaches the first part of the expansion chamber proper-which is a diffuser (commonly called a megaphone). The

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-36138919641224941882008-01-27T18:13:00.000+07:002008-01-27T18:15:34.581+07:00expansion chamber (2)

Actual percentage improvements between engines fitted with their standard mufflers and the same engines with expansion chambers will vary greatly. A lot depends on how good (or bad) their muffler happened to be, and on carburetor size, porting, etc. -any of which can impose limits that cannot be totally compensated by even the best of expansion chambers. In most cases, however, the improvement

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-56156123316967263272008-01-27T18:11:00.000+07:002008-01-27T18:12:49.232+07:00expansion chamber

Walter Kaaden was chief engineer of MZ's racing department through that firm's glory years on the Grand Prix circuit, and in that capacity Kaaden advanced the state of the art with regard to expansion chamber design very considerably. And one day while discussing the subject he remarked, only in jest, “You'll know when you have the design right, because the chamber will then be impossible to fit

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-38337203002092535872007-12-08T13:31:00.000+07:002007-12-08T13:39:17.902+07:00HEAD / CYLINDER SEALING (2)

Nominal compression ratios, as I have said before, have little meaning in high-output two-stroke engines. However, you can work with trapped compression ratios almost as effectively as by measuring cranking pressures. An engine's trapped compression ratio is the ratio between the cylinder volume at the moment of the exhaust port's closing and the volume with the piston at the top of its stroke.

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-46737485498163079062007-12-08T13:30:00.000+07:002007-12-08T13:31:42.385+07:00HEAD / CYLINDER SEALING

A major problem with cylinder heads on high-output engines that began life as low output engines is persistent leakage around the head/cylinder joint. The combined increases in temperature and pressure seem always to be too much for the joint, and you will find evidence of fire puffing past on the surfaces after disassembly even though you may not have observed anything out of the ordinary when

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-54967556554240013582007-12-08T13:29:00.002+07:002007-12-08T13:30:20.241+07:00PLUG LOCATION (4)

There is another solution to the problem that has nothing whatever to do with the cylinder head: you simply add metal to the piston crown, and that, too, will tend to equalize skirt temperatures - but it also makes the piston heavier. Even so, it is a solution much-loved by manufacturers, as adding thickness in the piston costs virtually nothing, while any departure from symmetry in combustion

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-719041327017210642007-12-08T13:29:00.001+07:002007-12-08T13:29:56.731+07:00PLUG LOCATION (3)

Not all cylinder heads have their spark plugs and combustion chamber pockets centered over the cylinder bore, and there are good reasons for most of the variations in form one sees in the products of the major manufacturers: For instance, piston crown temperatures seldom are even, and while the overall temperature distribution pattern is understandably inclined toward maximums in the center of

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-40756732543473816532007-12-08T13:26:00.000+07:002007-12-08T13:28:18.815+07:00PLUG LOCATION (2)

Fortunately, most engines usually are relatively insensitive to plug location as long as the gap isn't moved too close to the piston. Which raises an interesting point: The common practice of shaving material from the cylinder head's lower surface not only raises the compression ratio, and thus the thermal load on the piston, but it brings the plug gap close to the piston crown -compounding the

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-42642457628080372042007-12-08T13:24:00.002+07:002007-12-08T13:26:04.091+07:00PLUG LOCATION

Tests have shown that the best location for the spark plug is, by and large, squarely in the center of the combustion chamber, and with its gap as close to the center of the volume of trapped mixture as possible - which is logical, as that position provides the shortest flame travel in all directions. However, a number of other considerations do intrude. First, the plug gap will necessarily be

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-46087018557055206832007-12-08T13:24:00.001+07:002007-12-08T13:24:35.856+07:00SQUISH BANDS (7)

The clearance space between piston and cylinder head must be enough to avoid contact at high engine speeds, yet close enough to keep the mixture held there cooled during the combustion process. This vertical clearance between squish band and piston should not be greater than 0.060-inch, and it is my opinion that the minimum should be only barely enough to prevent contact -usually about 0.015-

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-64962957654456517182007-12-08T13:22:00.002+07:002007-12-08T13:24:09.350+07:00SQUISH BANDS (6)

But if you want to use a true (measured from exhaust-closing) compression ratio much over 6.5:1, on a high-output engine, combustion control beyond that afforded by a non-squish cylinder head will be necessary. Considerable variation is possible, but agood rule to follow is to make the cylinder head's squish band about 50-percent of the cylinder bore area. For example, in a 3-inch bore -which has

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-67451005662981583392007-12-08T13:22:00.001+07:002007-12-08T13:22:52.904+07:00SQUISH BANDS (5)

No matter what the compression ratio you ultimately use, it will have been influenced much more than you probably suspect by the combustion chamber configuration, and by certain gross characteristics of the head itself. Over the years, I have seen the fashion in combustion chamber forms swing back and forth, hither and yon, with first hat-section chambers in favor and then trench-type chambers,

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-46047485934636192502007-12-08T13:21:00.000+07:002007-12-08T13:22:21.504+07:00SQUISH BANDS (4)

In an engine intended purely for road racing, with a torque peak virtually coincidental with its power peak and driving through a very close-ratio transmission (enabling the rider to hold engine-speed within narrow limits), making this beggar's choice is a fairly straight-forward proposition: you play with jetting until the motorcycle runs fast. However, road racing conditions allow you to stay

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-52502753247242155892007-12-08T13:11:00.000+07:002007-12-08T13:21:29.105+07:00SQUISH BANDS (3)

One of the most undesirable side-effects that comes with too-high compression ratios is an enormous difficulty in getting an engine to "carburet" cleanly. When the compression ratio is too high, you'll find that an engine's mixture-strength requirement has a sharp hump right at its torque peak that no motorcycle carburetor can accommodate. You'll realize, after working with high-output two-stroke

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-76466980644318740982007-12-08T13:10:00.000+07:002007-12-08T13:11:26.365+07:00SQUISH BANDS (2)

Our application here, of course, is strongly biased toward maximum horsepower, and that points toward a squish-band head - which is what you will have in most motorcycles in any case. I will warn you, now, that it may be unwise to follow the old-time tuner's habit of increasing an engine's compression ratio as an opening gambit in the quest for better performance. Indeed, before your work is

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-1448781296591951652007-12-08T13:08:00.000+07:002007-12-08T13:09:20.887+07:00SQUISH BANDS

Ricardo solved the problem, once he had determined its nature, by lowering the underside of the cylinder head in that part of the chamber over the piston. Thus, most of the mixture was concentrated right at the ignition source, and would be more likely to burn without detonating. The small part of the mixture caught between the cylinder head's squish band and the piston was still subject to

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-73220033281538500462007-12-08T13:07:00.000+07:002007-12-08T13:08:35.876+07:00THE COMBUSTION PROCESS (3)

We have England's Harry Ricardo to thank for this type combustion chamber, which he created to cope with conditions that ceased to exist long before most of us were born. During the conflict that wracked Europe just after the turn of this century, there were not only shortages of internal combustion engine fuels, but the fuels available were of very poor quality – and would detonate severely in

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-70478804501498052112007-12-08T13:05:00.000+07:002007-12-08T13:07:08.897+07:00THE COMBUSTION PROCESS (2)

Should this detonation continue, it will overheat the engine's upper end to the point where ignition occurs before there is a spark: compression heats the mixture in any case, and when a lot more heat is added from the piston crown, etc., the mixture will bebrought to “pre-ignite”. Detonation has a very bad effect on power output; pre-ignition (thought by some to be the same phenomena) is even

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-57666907992438843732007-12-08T12:56:00.000+07:002007-12-08T13:05:35.794+07:00THE COMBUSTION PROCESS

Not too surprisingly, the equilibrium described is influenced by combustion chamber design-as is the point at which smooth burning gives way to the outright explosions we call detonation. This aspect, too, is widely appreciated, but not widely understood. In truth, most people have very little understanding of the events that follow ignition; events that are highly complex if studied with

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-58846725173884910802007-12-07T11:03:00.000+07:002007-12-07T11:04:44.742+07:00CYLINDERHEADS

For the Otto-cycle engine, of which the two-stroke is an example, there is a theoretical level of efficiency, in terms of converting heat into work, referred to in basic engineering texts as “air standard efficiency”. In this, it is assumed that the cylinder is filled only with dry air, and heat then added, which ignores the fact that in practice the air contains some moisture and a considerable

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-25361033725855012672007-12-07T10:42:00.000+07:002007-12-07T10:43:57.733+07:00CRANK ASSEMBLY

There are gains in power and reliability to be had from carefully aligning your crankshaft and main bearing bores, and in getting the cylinder axis precisely perpendicular to the crankshaft. As it happens, there is more variation in production tolerances when the various parts of a crankshaft are made than can comfortably be tolerated in a racing engine. Crankpin holes in flywheels are not all

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-7108444226158169612007-12-07T10:40:00.000+07:002007-12-07T10:42:24.531+07:00WRISTPIN/CRANKPIN BEARINGS (4)

Connecting rods should not be lightened, or even polished, unless you intend going all the way in this direction and will finish the job by having the part shot-peened. Forgings acquire a tough skin in the process of being pounded into shape, and I know of instances where connecting rods that were entirely satisfactory in standard condition promptly broke after having been polished. I do think,

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-74054677622560824082007-12-07T10:39:00.000+07:002007-12-07T10:40:42.533+07:00WRISTPIN/CRANKPIN BEARINGS (3)

Crankpin bearing failures also stem from the use of excessively heavy bearing cages. Sheer rotational speed is not enough to burst a cage of such small diameter and mass, but the fact that the cage must accelerate and decelerate, relative to the crankpin as the connecting rod swings, will cause difficulties unless the bearing cage is very light. In effect, the rollers must push the cage up to

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-37447018247642586902007-12-07T10:37:00.000+07:002007-12-07T10:39:26.532+07:00WRISTPIN/CRANKPIN BEARINGS (2)

McCulloch, the chain-saw people, have used an arrangement similar to the one just described for years, but they have reasons other than simply working around bearing cage failures at the wrist-pin end of the rod. It was discovered at McCulloch that failures at the crankpin bearing were traceable to the thrust washers most manufacturers of two-stroke engines use to center the rod on the crankpin.

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-8271384546598633612007-12-07T10:32:00.000+07:002007-12-07T10:37:52.866+07:00WRISTPIN/CRANKPIN BEARINGS

Back in the days when pistons were uniformly poor and two-stroke engines wouldn't be run very fast, wrist pin bearings were almost always a simple brass bushing. Such bushings work very well in four-stroke engines, but lubrication is much less lavish in the crankcase-scavenged two-stroke and added difficulties are created by the essentially uni-directional loads placed upon it, which prevent the

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-71743334218272271492007-12-07T10:15:00.000+07:002007-12-07T10:19:29.239+07:00Piston Rings (3)

Another point of trouble can be the ring's locating pin, and if you encounter difficulties with locating pins working loose, the source of the trouble nearly always will be in the exhaust port. The racing engine's very wide exhaust port (width representing, in extreme instances, up to 70-percent of cylinder bore diameter) leaves a lot of the ring's diameter unsupported when the piston is down in

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-57886508376349791762007-12-07T10:09:00.000+07:002007-12-07T10:10:05.889+07:00Piston Rings (2)

Ring sticking is a problem to be faced with all high-output two-stroke engines. Carburized oil may lock the ring in its groove after a remarkably short period of running if the ring lacks sufficient vertical clearance (usually, from 0.0015- to 0.0040-inch) or if the ring is located too near the piston crown. More frequently, the problem stems from the oil being used for lubrication, and it is

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-14059379153402092022007-12-07T10:05:00.000+07:002007-12-07T10:08:28.807+07:00Piston Rings

Of all the problems that can be experienced with a modified engine, those connected with the pistons' rings are the most insidious. Borderline sealing failures can send fire shooting down along the pistons' sides to cause seizures and/or holing of the piston crown that appear to be the result of lean mixture, excessive ignition advance or too-high compression, but are not. These failures are, I

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-18029167237668897972007-12-07T00:48:00.000+07:002007-12-07T00:49:03.240+07:00The piston (6)

Excessive deep clearance bands must be avoided, for they expose the sealing ring to too much heat, and heat has a devastating effect on the service life of a piston ring. But for these effects, there would be every reason to locate the ring as close to the piston crown as is mechanically possible, because we would then obtain the cleanest opening and closing of the ports; with the ring in its

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-75266561262327141022007-12-07T00:47:00.000+07:002007-12-07T00:48:28.159+07:00The piston (5)

Often, in modified engines, you will find that the straightforward increase in overall piston clearance by slightly enlarging the cylinder bore is not a complete answer. If the manufacturer has done his work properly, his pistons will, as they expand with temperature, assume a round shape when the engine is hot. Your problem will be that with the modifications you have made, more heat will be

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-3155357092955928022007-12-07T00:45:00.000+07:002007-12-07T00:46:57.435+07:00The piston (4)

Presumably, you will not have the facilities to alter whatever shape your engine's piston(s) may have, but you can vary running clearances by changing cylinder bore diameter. The problem here is one of “How much?” and I regret to say that it is a problem for which there is no convenient solution. Clearances, measured at the piston's maximum diameter, across its thrust faces, may vary from about

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-42430400828517240882007-12-07T00:40:00.000+07:002007-12-07T00:45:08.647+07:00The piston (3)

Unless you happen to be a piston manufacturer, there isn't much you can do about piston alloys, beyond seeking out pistons having a high silicon content. Neither is there anything you can do about piston shape - which is most unfortunate, because a piston is not, as it first appears, simply cylindrical. Even with the use of aluminum-silicon alloys, pistons do expand as they are heated, and they

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-86632963503343660532007-12-07T00:39:00.000+07:002007-12-07T00:40:01.694+07:00The piston (2)

With all that, high silicon-content piston alloys still are not universally employed. As it happens, such alloys do have their disadvantage, which is that they are difficult to manufacture. Just casting pistons of aluminum-silicon alloy is a task for specialists using specialized equipment; machining the raw castings into finished pistons is an even more formidable task. You may encounter this

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-68201995313037576562007-12-07T00:38:00.000+07:002007-12-07T00:39:14.783+07:00The piston

For a very long time subsequent to Dugald Clerk's creation of the two-stroke engine, the thermal limit was the only limit, but it was enough to hold power output from such engines to extremely modest levels. Then, as now, it was primarily a limit imposed by available piston materials. Cast-iron has its advantages in terms of wear resistance, hot-strength and low thermal expansion rates, and it

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-27299620691304843562007-12-07T00:35:00.000+07:002007-12-07T00:37:07.985+07:00The crank train

As was noted in the chapter of this book dealing with basics, power output from an engine of any given displacement is a function of gas pressure in the cylinder during the power stroke, and the number of power strokes per unit time. Implicit therein is the suggestion that the horsepower ultimately to be had from an engine has little to do with port shapes and port timings, exhaust systems,

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-59718079981110788712007-12-06T19:47:00.000+07:002007-12-06T19:51:19.456+07:00Piston Accelerator (3)

How short a time? That is at the same time one of the least complicated and most depressing calculations you can perform. Let us consider the Yamaha DT-1, which in fully developed configuration had an intake duration of 160-degrees, a transfer duration of 123-degrees, and an exhaust duration of 172-degrees. Yamaha claims a power peak at 7000 rpm. Let's have a look at the actual time, in

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-30235077928470817312007-12-06T19:33:00.000+07:002007-12-06T19:40:58.131+07:00Piston Accelerator (2)

To illustrate how high these forces may sometimes be, let's use as an example the Yamaha TD-2, using 11,000 rpm for N. The formula tells us that at that speed, maximum piston acceleration will be (with the answer rounded off by my slide rule; I'm too lazy to do it all with paper and pencil) no less than 135,000 ft/sec2. Now if you will recall for a moment that the acceleration of gravity is

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-34495695887686262232007-12-06T19:27:00.000+07:002007-12-06T19:33:38.640+07:00Piston Accelerator

Sadly, while there is no substitute for revs, there are plenty of barriers: piston speed is one, as was already noted. But that is a rather indirect limit, as it ignores the fact that it is not speed so much as all the starting and stopping of pistons that does the damage, or at least the worst of any damage. The acceleration forces generated by the starting and stopping are felt even in an

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-70654970257355638792007-12-06T19:21:00.000+07:002007-12-06T19:22:56.456+07:00Piston Speed

All this asks the question, “How does one determine the limit, with regard to engine speed?” Unfortunately, establishing this limit with any precision is not only extremely difficult in terms of the mathematics involved, but also requires data concerning metallurgy, etc., seldom available outside the record-rooms of the factories from which the engines originate. Still, there are guide-lines

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-19511504027117222912007-12-06T19:17:00.000+07:002007-12-06T19:20:31.411+07:00Predicting Power (2)

Assuming that the man who modifies the Kawasaki F-5 knows his business, but doesn't have all the development time in the world, (probability favors the latter far more than the former) then he very likely will arrive at a combination of porting, etc., good for a bmep of about 105 psi-which is about all that can be expected with a single cylinder of 350cc displacement. To expect more would be to

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-59588490666734780112007-12-06T19:04:00.000+07:002007-12-06T19:14:14.811+07:00Predicting Power

An average, well-developed stock engine intended for use in a sports / touring motorcycle will have a bmep of about 70 psi. It is possible, and I must stress that word "possible", to raise this to perhaps 115 psi- an improvement of some 64-percent, which (if accomplished) will yield a 64-percent increase in power output without raising the engine's operating speed. Similarly, a 64-percent

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-63430189530949875542007-12-06T13:39:00.000+07:002007-12-06T13:41:21.494+07:00FOUNDAMENTALS

Throughout this book it will be assumed, inconvenient though that assumption may occasionally be, that the reader has progressed to at least a superficial knowledge of the manner in which a piston-type internal combustion engine - with particular reference to those operating on the two-stroke cycle principle-converts quantities of fuel and air into useful power delivered at the end of its

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-46077919941121760722007-12-06T13:38:00.000+07:002007-12-06T13:39:45.982+07:00FOREWORD

Only ten years ago the two-stroke engine was widely and quite understandably thought to be a "reasonable alternative to the four-stroke only when minimum weight and manufacturing cost were all-important considerations. The two-stroke was recognized as having substantial theoretical promise, as it delivered a power stroke for each 360 degrees of crankshaft rotation but the hard reality was that

Fuenghttp://www.blogger.com/profile/07437915115935442008noreply@blogger.com0tag:blogger.com,1999:blog-782427749756456671.post-84510482944354052442007-12-06T13:09:00.000+07:002007-12-06T13:11:11.213+07:00Two-Stroke TUNER'S HANDBOOK

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