Enduro motorcycle
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An Enduro motorcycle is a motorcycle specially made for the Enduro sport, with the long travel and medium-hard suspension of a motocross bike conjoined with features such as a headlight and quiet muffler to make the bike street-legal for parts of the track. The engine of an enduro bike is usually a single cylinder 2-stroke between 125cc and 300cc, or 4-stroke between 250 and 650cc.
There can be an advantage to having an engine size smaller than 650cc in some Enduro events as it is nearly always lighter, which means it has easier handling for getting around trees, obstacles, etc. However, in some Enduro events, the larger bike sizes allow them to get up hills without going down a gear or even two.
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[edit] Manufacturers
Past and present Enduro manufacturers are:KTM, Kawasaki, Suzuki, Yamaha, Husqvarna, Maico, Bultaco, Montesa, Gas Gas and Hodaka.
[edit] Features and Construction
An enduro bike has a lot of differences between it and its cousins, with a lot of extras compared to moto/supercross bikes. These include:
- headlight for on road and after dark use
- brake light/tail light for on road use
- protective hardware like handguards for hand protection against branches and leaves
- Skid plate to protect the bottom of bike/motor against mud, logs, etc.
- Disk brake rotator protectors to help keep mud off the disk and from between the pads and prevent it sticking to the pads
- Frame guards to prevent damage
- An exhaust system that is street legal and meets regulations for noise and spark arresting
- ‘Wide’ gear ratios
- Narrower handlebars so that the bike can fit between branches and trees easily
- Front and rear suspension with enough travel and the ability to be set for preload
- comprehensive/rebound dampening so that the rider can customize the performance of the suspension for his/her physiology, riding style/preferences and the particular terrain of any given Enduro event
- A roll chart holder/Enduro computer.
Enduro motorcycles most closely resemble Motocross (MX), and MX bikes are often selected by many riders for Enduro racing (albeit with significant modification, such as those described above). The demands that Enduros place on a bike are severe, and compared to standard street motorcycles, Enduro bikes require a great deal of maintenance to maintain peak operating capability. Their maintenance can be compared to that of Motocross bikes, except that Enduro bikes tend to require more collision prevention/repair maintenance and, until recently, Enduro bikes were developed by their manufacturers as totally different bikes than MX bikes (which is why many races rode/ride MX bikes in Enduro events), and accordingly they were developed with longer service-life engines, more durable components, less concern for weight (since, unlike MX, there are often no lower-limits on bike weights in a class), and other Enduro specific considerations.
The trend since the early 2000s, though, has been to use MX racing bikes as the platforms for Enduro bikes. This was partially driven by the conversion of MX from 2-stroke to 4-stroke engine designs to comply with regulatory trends. Enduro or so-called "Trail-bikes," or "Dual-Sports" (dual because they are capable of moderate off-road and moderate street-performance, while excelling at neither) traditionally had a much higher proportion of 4-stroke models. The power-to-weight ratio of these 4-stroke trail bikes wasn't great by today's standards, and that had to do with the lack of emphasis on meeting a weight lower-limit. When the conversion to 4-stroke MX bikes began, there was suddenly an emphasis on power-to-weight ratios for off-road 4-stroke motorcycles, because 125 and 250 MX classes have minimum weight limits. Once these bikes entered production, the manufacturers decided that rather than inventing the next generation of Enduro type 4-stroke bikes, they would simply re-configure their existing 4-stroke MX lineup for Enduro. Accordingly, they made the above listed configuration changes.
The end result of all of this is that today's Enduro motorcycles, which are predominantly 4-strokes are lighter and more powerful than ever, but have many of the same characteristics of their MX cousins. These bikes, which were originally engineered to be MX bikes, do not often stand up to the rigors of long-term Enduro use. In the quest to achieve lower weight and higher power, the manufacturers made many compromises (i.e., thinner walls, lighter materials, more stressful designs, etc...), the downsides of which aren't always evident in MX where the races are relatively short and the bikes are thoroughly serviced after each event and replaced after every season for serious riders. In the case of Enduro riding, these compromises became painfully evident when the bikes were subjected to the harsh Enduro operating conditions. One such example is the 2004 Honda CRF250X Enduro bike, which was based on the CRF250R MX bike. The valves were notorious for needing to be constantly adjusted and even replaced in many cases. Neither procedure is trivial. This issue has apparently been rectified on the 2006 models, due to a reported valve-seat material change on the cylinder head. In contrast, the comparable Husqvarna model TE250, which is purpose built for Enduro riding, is not only low maintenance by comparison, but the types of maintenance that are required more frequently on bikes that are used in Enduros are much easier to do because the bike was designed with those procedures as a design concern, such as valve checks and adjustments.
[edit] Motor Vehicle Registration Requirements
Another common issue with Enduro bikes is the need to register them with local government motor vehicle agencies. In the United States, for example, vehicle registration is a common requirement of regional Enduro sanctioning bodies. Since many of today's Enduro bikes are directly derived from their MX counterparts, they don't come with a "street-legal" title. That means that their title explicitly states that they are for non-highway use only. Many states will not permit the registration of vehicles with such titles for on-highway use. Some states have off-road only registrations, but these are not valid for participating in Enduros where the sanctioning body requires a registration, because the purpose of requiring the registration is to validate the use of public lands that are used in the event, as well as to validate the use of public roads that are "laisons" between different off-road sections of the course. Purpose-built Enduro bikes, such as the Husqvarna TE250, some Husabergs, and a select few others come with standard street-bike titles. The bikes that don't come with street-legal titles come instead with an "MSO," a Manufacturer's Statement of Origin, which is nothing more than a document that proves legal title to the bike, but that usually cannot be used for motor vehicle agency registration, depending on the state. Some more liberal states include Pennsylvania and Vermont, where as New York and New Jersey apply much more scrutiny. California has some unique regulations that require certain California-only emissions modifications. The quest to register Enduro bikes has become a cat-and-mouse game between Enduro riders and their state motor vehicle agencies, and manufacturers that offer competitive bikes that come with street-legal titles are at a huge marketing advantage.
[edit] Racing Classes
Motorcycles race according to their engine type and size, and classes vary by sanctioning body. Certain European classes include:-
- Enduro 1 - 100-125cc 2-stroke / 175-250cc 4-stroke
- Enduro 2 - 175-250cc 2-stroke / 290-450cc 4-stroke
- Enduro 3 - 290-500cc 2-stroke / 475-650cc 4-stroke
In America, AMA machine-type sub-classes (modifications to the standard AA, A, B, and C classes) are often based on the engine type (i.e., 4-stroke vs. 2-stroke) and/or a characteristic of the rider (usually age, i.e., "Veteran," class).
