Editing V-twin engine (section)

==Motorcycles==
{{See also|List of motorcycles by type of engine#V-twin}}

As per other motor vehicles, the terms [[longitudinal engine]] and [[transverse engine]] are most often used to refer to the crankshaft orientation relative to the frame.<ref name="Cossalter">{{cite book
| title = Motorcycle Dynamics
| edition = Second
| last = Cossalter
| first = Vittore
| year = 2006
| publisher = Lulu.com
| isbn = 978-1-4303-0861-4
| pages = 291–294}}{{self-published source|date=January 2021}}</ref>{{self-published inline|date=February 2020}}<ref name="Foale">{{cite book
| title = Motorcycle Handling and Chassis Design: the art and science 
| url = https://archive.org/details/motorcyclehandli00foal
| url-access = limited
| edition = Second
| last = Foale
| first = Vittore
| year =2006
| publisher = Tony Foale
| isbn = 978-84-933286-3-4 
| pages = [https://archive.org/details/motorcyclehandli00foal/page/n344 11]–6}}</ref> However, some companies use the opposite terminology, stating that a "transverse" V-twin engine has the cylinders mounted on each side of the motorcycle (therefore with the crankshaft running in line with the frame) and that a "longitudinal" V-twin engine has the cylinders at the front and rear.<ref name="Combined">* {{Cite book |last1=Coombs |first1=Matthew |url=https://books.google.com/books?id=D0DhHAAACAAJ |title=Motorcycle Basics |last2=Haynes |first2=John |last3=Shoemark |first3=Pete |publisher=Haynes |year=2002 |isbn=978-1-85960-515-8 |edition=2nd |page=1•31 |quote=The transversely mounted &#91;cylinder&#93; V-twin, as used to good effect for many years by Moto Guzzi, slots easily into the frame, and has excellent cooling as both heads are stuck out into the wind.  It also provides the perfect set-up for using shaft drive. }}{{Dead link|date=November 2023 |bot=InternetArchiveBot |fix-attempted=yes }}
* {{Cite book |last=Holmstrom |first=Darwin |url=https://books.google.com/books?id=VGrp5Pjsf4UC&pg=PA82 |title=The Complete Idiot's Guide to Motorcycles |publisher=Alpha Books |year=2001 |isbn=978-0-02-864258-1 |quote=Ducati's engines, which are longitudinal (they are positioned lengthwise in the frame) most obviously display the "L" configuration, but Moto Guzzi's engines, which are transverse (arranged croswise in the frame), are also at 90 degrees. }}
* {{Citation |title=New 2009 Moto Guzzi V7 Classic Honors Historic Roots |url=http://www.motoguzzi-us.com/servonline/news/dettaglio.asp?indice=271 |access-date=2009-04-29 |archive-url=https://web.archive.org/web/20090528073549/http://www.motoguzzi-us.com/servonline/news/dettaglio.asp?indice=271 |publisher=Moto Guzzi Spa |quote=Just as importantly, the V7 became an instant technology trendsetter thanks to its innovative transverse, air-cooled V-twin engine with shaft drive. |ref=none |archive-date=May 28, 2009 }}
* {{Citation |title=Out of history, on to the road. |url=http://www.motoguzzi-us.com/servonline/news/dettaglio.asp?indice=271 |access-date=2009-04-29 |archive-url=https://web.archive.org/web/20090326002937/http://www.motoguzzi-us.com/Nuovi_modelli/breva1100/specifiche4.asp?pagina=spec&modello=breva1100&pag=4 |publisher=Moto Guzzi Spa |quote=We could, of course write a book about Moto Guzzi’s transverse V-Twin. |ref=none |archive-date=March 26, 2009 }}
* {{Cite book |last=Grubb |first=Jake |chapter-url=https://books.google.com/books?id=aeMDAAAAMBAJ&pg=PA82 |title=Popular Mechanics |date=March 1975 |publisher=Hearst Magazines |volume=143 |page=82 |chapter=Easy Riders Grand Touring Motorcycles for '75 |issn=0032-4558 |quote=Ducati 750 Sport with its clip-on handlebars and racing setup, is for those who want to do their touring stretched out prone!  Engine is a longitudinal V-twin. ..The unique 90∘longitudinal engine produces enormous low and mid-range torque...Moto Guzzi 850T...An 850-cc 90° transverse V-twin engine... |access-date=2009-04-29 |issue=3 }}</ref> The latter terminology is used by the Italian manufacturer Moto Guzzi.<ref>{{Citation |author-link=Susan Carpenter |first=Susan |last=Carpenter |title=Chaps aren't de rigueur, but a helmet, yes |work=ASK THROTTLE JOCKEY |url=http://www.latimes.com/classified/automotive/highway1/la-hyw-qa25jul25,1,2706840.story |quote=According to my source at Moto Guzzi Technical Services, "The Guzzi engine is a 90-degree 'L' twin, actually, because the cylinders are oriented at 90 degrees, instead of a typical V twin that has a smaller angle ( 60-degree, 77-degree, etc.). It is called 'transverse' because the engine is mounted with the crankshaft oriented front to back instead of left to right. Because of this you cannot run a chain or belt drive directly to the rear wheel like in most motorcycles. This is why you have a separate gearbox that bolts to the engine and transfers the power to the rear wheel via the drive shaft. This is how it is done on the Moto Guzzi and a BMW. |date=2007-07-25 |url-status=live |archive-url=https://web.archive.org/web/20131221081941/http://www.latimes.com/classified/automotive/highway1/la-hyw-qa25jul25,1,2706840.story |archive-date=2013-12-21 }}</ref>

To avoid such ambiguity, some people use descriptions of "transverse crankshaft engine", "longitudinal crankshaft engine",<ref name="Cossalter"/><ref name=Cocco>{{Citation |title=Motorcycle design and technology |first=Gaetano |last=Cocco |publisher=MotorBooks/MBI Publishing Company |year=2004 |isbn= 978-0-7603-1990-1 |pages=117 ff}}</ref> or "transversely mounted cylinders".<ref name=BMW>{{Citation |url=http://www.bmwmotorcycles.com/pdfs/history/design_tech.pdf |archive-url= https://web.archive.org/web/20070927231254/http://www.bmwmotorcycles.com/pdfs/history/design_tech.pdf |archive-date= September 27, 2007 |publisher= [[BMW Motorrad]] | title=Heritage/History: Design/Technology |quote= ...the boxer had three unique innovations that would remain throughout its years in development:The engine design included transversely mounted cylinders, which were cooled by exposure to the passing air.}}</ref>

===Transverse engine===
The most common arrangement is to mount the engine with the crankshaft oriented transversely to the frame. The advantage of this mounting is that the width of the motorcycle can be smaller than a longitudinally-mounted V-twin.<ref name="MDTCocco117">{{cite book| last = Cocco| first = Gaetano| title = Motorcycle Design and Technology| url = https://books.google.com/books?id=Ydk0bgq2_3YC| access-date = 2013-05-28| year = 2004| publisher = MotorBooks International| location= St. Paul, MN US| isbn = 0-7603-1990-1| page = 117| chapter = Chapter 11 The Engine| chapter-url = https://books.google.com/books?id=Ydk0bgq2_3YC&pg=PA113| quote = In some construction layouts the transverse width is the same as a single-cylinder engine, which allows very narrow frames and bodywork with small frontal areas.| ref = MDTCocco| url-status = live| archive-url = https://web.archive.org/web/20150205231651/http://books.google.com.jm/books?id=Ydk0bgq2_3YC&source=gbs_navlinks_s| archive-date = 2015-02-05}}</ref> A disadvantage of this configuration for air-cooled engines is that the two cylinders receive different air-flows and cooling of the rear cylinder tends to be restricted<ref name="CWMay2005Service160">{{cite journal | last1 =Dean | first1 =Paul | editor-last =Edwards | editor-first =David | date =May 2005 | title =Service: Oil miser | journal =[[Cycle World]] | volume =44 | issue =5 | page =160 | location =[[Newport Beach, California|Newport Beach]], CA US | publisher =Hachette Filipacchi Media | issn =0011-4286 | access-date =2013-05-26 | url =https://books.google.com/books?id=E86bEyC7DzoC&q=V-twin+%22rear+cylinder%22+cooling&pg=RA5-PA60 | quote =An air-cooled big-bore V-twin in particular can get very hot, especially the rear cylinder, which is not exposed to as much cooling air as the front. | url-status =live | archive-url =https://web.archive.org/web/20140415094643/http://books.google.com.jm/books?id=E86bEyC7DzoC&pg=RA5-PA60&dq=V-twin+%22rear+cylinder%22+cooling&hl=en&sa=X&ei=GlKiUY6UN43S9gSkoYCgBg&ved=0CCoQ6AEwADgo#v=onepage&q=V-twin%20%22rear%20cylinder%22%20cooling&f=false | archive-date =2014-04-15 }}</ref> (although the uneven cooling isn't as pronounced as a parallel-twin engine, where the inner faces of the cylinders are not exposed to any airflow). Some transverse V-twins use a single carburettor in the middle of the V-angle to feed both cylinders. While this avoids the need for two carburettors, it creates further cooling problems for the rear cylinder by placing its hot exhaust port and pipe at the back of the cylinder, where it may be exposed to less cooling airflow.

Transverse V-twin engines have been used by [[Harley-Davidson]], [[Ducati]] and many recent Japanese motorcycles, such as the [[Suzuki SV650]]. Some Ducati V-twin engines have been marketed as "L-twin" engines, due to the front cylinder being vertical and the rear cylinder being horizontal, thus forming an "L" shape.

<gallery mode="packed" ;="" heights="150px">
File:Princeps V-Twin Motorcycle 1902.jpg |1902 Princeps V-Twin {{nobr|(air-cooled)}}
File:Sokol 995 cc zijklep v-twin.jpg |1933–1939 [[Sokół 1000]] {{nobr|(air-cooled)}}
File:Ducati Monster 620 Dark.jpg|2002 [[Ducati Monster|Ducati Monster 620]] {{nobr|(air-cooled)}}
File:Honda VTR250 2009 Engine Radiator.JPG|2009 [[Honda VTR250]] {{nobr|(water-cooled)}}
</gallery>
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===Longitudinal engine===
A less common arrangement is to mount the engine longitudinally. An advantage of this arrangement is that both cylinder heads can protrude into the air stream, so they can each receive the same amount of cooling (for air-cooled engines).<ref name=Coombs>{{Citation |last1=Coombs |first1=Matthew |last2=Haynes |first2=John |last3=Shoemark |first3=Pete |title=Motorcycle Basics |edition=2nd |publisher=Haynes |year=2002 |page=1•31 |isbn=978-1-85960-515-8 |url=https://books.google.com/books?id=D0DhHAAACAAJ }}{{Dead link|date=November 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> Also, the transmission being located behind the engine is easier to fit within a typical motorcycle frame and, for shaft-drive motorcycles, a 90° [[bevel gear]] is not needed at the start of the driveshaft.

As per all longitudinal engines, a disadvantage is that the torque reaction will twist the motorcycle to one side (such as on sharp acceleration/deceleration or when opening the throttle in neutral) instead of shifting the weight balance between the front and rear wheels. However, many modern motorcycles reduce this effect by rotating flywheels or [[alternator (automotive)|alternator]]s in the opposite direction to that of the crankshaft.<ref name="MotoCruiserApr2000">{{cite web| url = http://www.motorcyclecruiser.com/roadtests/sport_cruisers_comparison/index.html| title= Sport Cruisers Comparison - Seven Sport-Cruiser Motorcycles| first1= Art| last1= Friedman| first2= Andrew| last2= Trevitt| first3= Andrew| last3= Cherney| first4= Jamie| last4= Elvidge| first5= Evans| last5= Brasfield|date=April 2000| work= Motorcycle Cruiser| publisher= Source Interlink Media| at= "Take a Spin" section, paragraph 4| access-date= 2010-09-10|archive-url=https://web.archive.org/web/20100502180324/http://www.motorcyclecruiser.com/roadtests/sport_cruisers_comparison/index.html |archive-date=2010-05-02|url-status=live| quote= Though the Valkyrie also has a longitudinal crankshaft, this torque reaction has been eliminated by making some of the components, such as the alternator, spin the opposite direction of the engine.}}</ref><ref name="TamingTheBeast">{{cite web| url = http://www.breganzane.com/vm/history/v6/page3.html| title= Developing the V6 - Taming The Beast| first= Stephen | last= Battisson | year= 1997| work= The Laverda V6| publisher= Stephen Battisson| page= 3| access-date= 2010-09-10| archive-url =https://web.archive.org/web/20110708092245/http://www.breganzane.com/vm/history/v6/page3.html | archive-date =2011-07-08 | url-status = dead| quote= By arranging the rest of the engine internals to rotate in the opposite direction to the crankshaft their forces are cancelled out without having to resort to the weight, complexity and friction associated with two crankshafts.}}</ref>

Longitudinal V-twin engines have been used by the [[Honda CX series]] and several [[Moto Guzzi]] motorcycles.

<gallery mode="packed" heights="200px">
File:Honda Longitudinal V-twin.JPG |1978–1983 [[Honda CX series|Honda GL500 Silver wing]] {{nobr|80° V-twin}}
File:Moto Guzzi V-twin.JPG |2000 [[Moto Guzzi#2000–2004 – Aprilia years|Moto Guzzi Jackal]] {{nobr|90° V-twin}}
</gallery>
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