Talk:Motorcycle engine

Standardized Terminology

There needs to be a concensus on the descriptive terms used to describe motorcycle engines. For example most 4 cylinder engines are in-line fours, most Japanese four cylinder engines are transversely mounted (that is across the frame) but others like the Indian, Nimbus and BMW K100 are longitudinally mounted. All however are inline fours as opposed to horizontally opposed fours, square fours or V4s.

The usual description for a transversely monted inline twin motorcycle is parallel twin with inline twin usually being reserved for an engine layout like the Sunbeam S7/8.

Also remember geographical bias when claiming that one layout is the most common. While V-twins may be the most common twin in the US, parallel or horizontally opposed are more common elsewhere.

Displacement

Actually two-stroke motorcycle engines can, and hi-performance ones do, have more displacement then cylinder size might suggest. This is due the crank-case acting as a Supercharger-like compressor before intake air is spooled, thus over-filling the cylinder with 'boost' if you will.

turbo-charged engines over-fill aswell ofcource... —Preceding unsigned comment added by 212.187.71.66 (talk) 12:37, 25 May 2008 (UTC)

The pumping displacement is limited to cylinder volumetricity unless a two stage piston is used as most recently used by Hooper. The crank case is only a storage area and it's volume is generally irrelevant to pumping volume. M-72 (talk) 21:39, 25 May 2008 (UTC)

Well allow me to disagree: provided the crank case volume is next to nil - when the piston goes up opening the reed valve fillling a cylinder size of fresh air; and goes down again closing the reed valve and compressing the air top of piston opens spool ports just before BDC, compressed air filles the cylinder pussing out the exhust port(s) a bit, meantime in the crank case new air being more dense opens the reed valve, piston closes spool ports, fresh filling having been pushed out the exhust gets pussed back in by (sonic) pipe backpressure, exhust port closes while underpressure is again filling a cylinder size of fresh air. —Preceding unsigned comment added by 212.187.71.66 (talk) 23:01, 25 May 2008 (UTC)

See Volumetric efficiency for more info —Preceding unsigned comment added by 212.187.71.66 (talk) 15:18, 30 April 2009 (UTC)

Displacement is Pi times one half of the bore, squared, times the stroke. Nothing more or less.Krontach (talk) —Preceding undated comment added 00:59, 24 May 2011 (UTC).

Except for a bit of pi. --Biker Biker (talk) 01:04, 24 May 2011 (UTC)

Yes, of course. How do you spell PI? Krontach (talk)(correctionKrontach (talk))

Incorrect Engine diagrams

Comment on the engine diagrams: the classic V-twin has a single crank pin shared by both cylinders, not dual crank pins as drawn.Rracecarr 00:53, 11 May 2006 (UTC)

Agreed. The drawing is incorrect, but is there an editor watching this page? Seasalt 04:47, 26 November 2006 (UTC)

Agreed - propose removing this sketch until someone comes up with something correct. TomRawlinson (talk) 21:37, 13 December 2008 (UTC)

Sounds like you are trying to favor one brand over another. Are you talking about the V-Twin design from Daimler/Maybach (the original), The 1902 Clement, the 1930 Brough Superior, The Transverse V-Twins from Victoria, Moto Guzzi, Honda, or others? Many archaic brands use a single crank pin. A modern V-Twin might not. This sounds like you are trying to promote a single type over another type largely because you know of few of the others. V-twin crankshafts have both single and double crankthrows. V-Twin engines vary quite a bit in V angle. Some of the Honda V-Twins are also Turbo-Charged. Are you favoring one brand over another... I think you are. The solution is not to restrict the discussion to one type, but to include all types if you want to claim to be encyclopedic. Krontach (talk) 07:23, 26 May 2011 (UTC)

Workpage shows formatting without table

On the workpage I have reformatted this article with conventional section formatting instead of a table in the cylinders and configuration section. I'm not sure which one is better. Probably it's better to keep it simple, for long-term maintenance. --Dbratland (talk) 23:52, 10 December 2009 (UTC)

Transverse vs Longitudinal - just so there is no confusion

There has been some confusion in this article, hopefully now cleared up, about longitudinal vs. transverse. But I just wanted to state the following for the record so that this and all other motorcycle articles use the correct terminology.

A longitudinal engine is one where the crankshaft is oriented from front to back i.e. along the long axis of the bike.

A transverse engine is one where the crankshaft is oriented from left to right i.e. across the short axis of the bike.

The confusion mostly seems to arise with V-engines and flat-twin engines as people think about orientation of the cylinders, which is opposite to the crank orientation. In a v-twin or flat twin which has cylinders poking out of either side of the bike (as with Guzzi & BMW) the crank is oriented longitudinally, so this is a longitudinal engine. The typical American and Ducati v-twin configuration with one cylinder oriented towards the front and one towards the back has the crank oriented transversely, so this is a transverse engine. --Biker Biker (talk) 09:42, 31 December 2009 (UTC)

This is discussed at Talk:V-twin#Transverse_vs_Longitudinal. Personally I would like it if we could take it for granted that you always orient by the crankshaft, but there are too many reliable sources who arbitrarily decide the engine's centerline passes from one cylinder to the other if it's a twin. Most notoriously, Moto Guzzi. In a Susan Carpenter column, cited in the dissuasion above, she tried to get a Guzzi representative to explain, but his answer was even more confusing. Possibly something lost in translation. Just yesterday I ran across yet another instance -- Roland Brown's Honda: The complete story (p. 38), where the Honda CX500 was described as having a transverse v-twin.

Because so many sources are inconsistent about this, the safest thing is not say "transverse engine" but try to say "transverse crankshaft engine" so that it's clear you're talking about the crank. Gaetano Cocco in Motorcycle design and technology follows this practice. It's awkward, but I don't know any other solution unless WP can make a proclamation that everyone who says it the other way is officially wrong. --Dbratland (talk) 18:17, 31 December 2009 (UTC)

I'm with Biker Biker. It's unfortunate that so much of the literature is written by non-mechanically minded pencil prostitutes but we shouldn't allow their honeyed words to mislead us and hi-jack our understanding of precision language. MalcolmMcDonald (talk) 21:55, 20 January 2010 (UTC)

Moto Guzzi -- the entire company -- is "non-mechanically minded pencil prostitutes"? Not to mention Darwin Holmstrom?

That is not now Wikipedia works. You don't get to just ignore sources because you disagree with them. I understand how much easier it would be if we could just decide to rationalize irrational things on our whim, but we can't. If we could do that, we could erase the difference between British and American spelling, and forget about constantly converting metric units. There are lots of Wikipedia policies that cover this sort of thing, but the most relevant might be Righting Great Wrongs and Wikipedia:Advocacy. As in, Wikipedia cannot right them. Wikipedia cannot teach the world to use the "correct" terminology. Maybe they are wrong, and we can certainly convey what the various authorities say on this subject, but we can't fix it. It is not our job to fix it. --Dbratland (talk) 23:18, 20 January 2010 (UTC)

To clarify, I agree all articles should, by default, consistently treat the crankshaft, not the line between the cylinders, as the axis of the engine. All I'm saying is, this should not be treated as truth of any kind, merely convenience. And where possible, it should be preferred to explicitly say "transverse crankshaft engine" rather than just "transverse engine". And any article that wants to say it is "wrong" to orient the other direction, needs to have a source to an authority who calls it wrong. That's all. --Dbratland (talk) 00:19, 21 January 2010 (UTC)

I can see the danger of having a house-style for motorcycle articles and deciding eg that alignment must be described on a crankshaft basis, not a cylinder basis. However, we're also in the business of producing well-written article that are clear and informative. We do that by sticking generally to a single standard, explaining wherever and whenever it's appropriate that our use of language is nationality biased and perhaps not universally accepted. Moto-Guzzi owners take pride that their heads are at an angle to everyone else's and their language has a word for spaghetti while ours does not. But there's just no way we can keep them happy when they employ non-engineers in their marketing department.

A separate note along the lines of "see this discussion on assumptions being made" is probably better than cluttering the flow by inserting "crankshaft" repeatedly. In so many cases (eg the confusing business with underbones/scooters) it would be impossible to explain what we're doing every time it arises. MalcolmMcDonald (talk) 16:53, 21 January 2010 (UTC)

Agree. We should explain in simple terms, and not clutter everything up with exceptions and qualifiers and so on. But we should also find some place to have a detailed explanation that includes minority points of view. --Dbratland (talk) 19:23, 21 January 2010 (UTC)

Minority view points are very important. But we can't write articles including statements such as: "Himalayan glaciers are shrinking drastically or maybe they're not really". We have to present something free of confusion, and then state that there are alternatives, even including such really weird ones, in which transverse=longitudinal and vice-versa. MalcolmMcDonald (talk) 21:59, 21 January 2010 (UTC)

manufacturers linked with specific engine layouts

" Japanese manufacturers are not linked to any one layout in the same way and Honda, in particular, have produced almost every possible configuration and type." who wrote this, yes Japanese manufacturers have produced alot of different ones but they are heavily linked with in-line four stroke engines, might consider changing this, maybe revising the entire paragraph cause its not very well written the way it is. —Preceding unsigned comment added by 94.5.175.150 (talk) 19:10, 16 December 2010 (UTC)

I don't consider this to be a valid concept. We could say that since the VAST majority of Honda's 210 MILLION motorcycles sold are single cylinder machines that Honda makes primarily singles. But 16 million of these by the mid-80s were CB750s alone. So in that size class Honda makes primarily inline transverse fours. In their 1800cc size, they make both V-Twins and Flat Sixes, but primarily flat sixes. We don't have enough production (which means numbers of units made and sold to the public, not made and shipped to dealers and financed by in house credit [which is called channel stuffing and resulted in a class action law suit against Harley-Davidson when their stock tanked], not the year of production), information to say this by the way. (which is to say that Harley-Davidson's claimed sales figures even they are still in decline are overstate) The V-Twin is popular in the USA, but the vast majority of other nations have other choices. The best seller in South Africa, for example with about 65% of the market is the BMW R1200GS, a flat twin. The best seller in Thailand, Vietnam, Cambodia, Laos, China, and India which is over 90% of the motorcycle market) is the single. Krontach (talk)

This category smacks of chavinism. Krontach (talk) —Preceding undated comment added 07:43, 26 May 2011 (UTC).

It's an observation I added because a number of sources said it. But it's my fault for not including citations. I have no problem with deleting it now and putting it back when I've found the sources again. It's mostly commentary about how the smaller companies focus their engineering knowledge on a single technology while the larger ones can operate on a scale that lets them develop many different technologies. Many observers consider Honda remarkable in this regard, even more than other conglomerates, in their willingness to invest in so many diverse technologies. Not just engines, but transmissions, electronics and more. Conversely, Harley-Davidson is remarkable in that they are large enough to research multiple technologies, but they choose to work with only one. At some point I'll gather more sources and clarify it. --Dennis Bratland (talk) 16:13, 26 May 2011 (UTC)

Steam Engine

If you are going to include steam veolcipedes then there should be an infobox for these types of engines. This should include:

• Manufacturer
• Date of Manufacture
• Type of Fuel (whether wood, oil, charcoal, coal)
• Fuel Capacity
• Type of Boiler
• Operating pressure
• Engine types (whether piston, turbine, rotary, Lear) etc.
• Number of cylinders
• Valve type (sliding box, rotary, poppet, sleeve) etc.
• Start up time (typically 20 minutes to an hour)
• Water Injection type
• Water capacity
• Operating Range
• Brake Type (whether shoe, air brake, hand actuation)
• Brake Actuation (manual, automatic)

And this should also be consistent with the terms used to rank Steam Locomotive engines. There are very good reasons why steam doesn't exist as a viable drive type for transport machines. One is a lack of safety. Another is lack of range. There isn't going to be a relevant AMOUNT of information on these anecdotal machines for many of these relevant steam description categories to be answered. I submit that steam should NOT be included as it lead NO WHERE and such machines are singular. If you can show me a successful steam motorcycle manufacturer then by all means include it. If you can't I suggest you stop increasing the noise level with unimportant trivia such as anecdotal steam velocipede acknowledgement. Krontach (talk) 07:06, 26 May 2011 (UTC)

Steam engines are included for the simple reason that the majority of reliable sources include them when reviewing the early history of motorcycles. We aren't making up our own concepts here, we're going where our sources lead us. The reasons for going where our sources lead us are found in Wikipedia:Five pillars, Wikipedia:Neutral point of view, Wikipedia:Verifiability, and Wikipedia:No original research.

If you have a reliable source you can cite who states that they do not think steam motorcycles count as motorcycles, then you should add a citation of their opinion. The only one I know of is Cycle World's Kevin Cameron, and I've repeatedly cited his opinion on Roper steam velocipede, Michaux-Perreaux steam velocipede and Daimler Reitwagen. I don't think we need to belabor that point further. It's a minority view and WP:UNDUE places limits on how much attention you give to minority views. --Dennis Bratland (talk) 16:04, 26 May 2011 (UTC)

Electric Motorcycle Engines

Is it time to include this class of engines or are we going to be technical and exclude electric because they are motors? — Preceding unsigned comment added by Kellnerp (talk • contribs) 00:58, 3 February 2012 (UTC)

They're not excluded. There's a section on electric engines, tagged for expansion. Expand away. --Dennis Bratland (talk) 02:08, 3 February 2012 (UTC)