By the time World War I broke out, Indian was the largest U.S. manufacturer and was producing 20,000 units per year. The war brought about a huge increase in bike production because they could be used in a number of combat situations, essentially replacing horses. This gave a boost to manufacturers such as the 10-year-old Harley-Davidson Co., which by 1918 was selling roughly half of its production to the U.S. Army.

After WWI new names began to appear in the U.S. market, but by the early 1930s, Indian and Harley-Davidson were essentially the only domestic heavyweights still standing. World War II continued to see growing motorcycle production, but once again, most were diverted to military needs. After that war, civilians finally could buy motorcycles for personal use again, and that led to a large increase in designs and manufacturers, as well as more European and Japanese imports. The postwar period also saw the introduction of two-stroke cycle engines which were favored for their high power-to-weight characteristics and lower cost.

Today, some of the biggest players are U.S.-based Harley and the U.K.s Triumph in the four-stroke cycle engine area, and Japans Honda, Kawasaki, Suzuki and Yamaha in the two-cycle category. However, there are hundreds of motorcycle manufacturers worldwide. Youll find them building on-road, off-road and racing bikes, scooters, all-terrain vehicles and more, in the United States, China, India, Japan, Brazil, but also Italy, Germany, Austria, Thailand – everywhere!

Globally, there are more than 300 million units, counting both two- and three-wheeled varieties. By region, Asia is far and away the leader with almost two-thirds of the total; more than 100 million are in China alone. China is also the world-beater in terms of motorcycle production; it built 27 million bikes in 2011. India built 15.4 million bikes that year, and 8 million units roared out of Indonesias plants. By comparison the United States lags sadly, with a motorbike population of around 10 million and production of less than 500,000 units a year.

How a motorcycle is used varies depending on what part of the world you live in. In the developing nations, motorcycles are the primary form of transportation. To grasp that fact all you need is to see a picture of a street in India or Indonesia or Vietnam, choked with motorbikes, scooters and three-wheelers. In Thailand and Indonesia, one motorcycle is in use for every four persons, estimates the Japan Automobile Manufacturers Association; in Vietnam and Malaysia, its one for every three persons.

Contrast that with the United States, where riders largely use their bikes for recreational purposes, and put only about 1,000 miles per year on their odometers. Demographically, too, the U.S. rider tends to be an older buyer with disposable income to spend. (Two out of three Harley-Davidsons are bought by Caucasian men 35 and older.)

Given that motorcycles are here to stay and have carved out an enthusiast niche in the U.S. marketplace, what are some of the lubrication needs and issues that are unique to bikes? In my search for answers, I contacted Dave Stiteler, an old friend and former business associate, for his take on the four-cycle motorbike segment. Dave has ridden and rebuilt Harley-Davidson bikes for some time and has some good insights into lubrication needs for Hogs.

As far as performance is concerned, he pointed out, these engines run hotter and at higher revs than a passenger car engine, so good oxidation resistance and shear-stable polymers make sense. Drain intervals are typically about 1,000 to 1,500 miles, and Harleys typically hold from 3.0 to 3.5 quarts of oil.

Dave lives in an area of the country that is seeing some pretty cold temperatures this year. He says that an SAE 30 is good enough for the old iron engines in winter; he even drops down to an SAE 10W-30 for his Evo engine to make it possible to start in the cold mornings.

Looking back, Dave noted that the old Harleys were powered by iron block engines of various configurations. Commonly known by nicknames such as Flathead, Panhead, Shovelhead and Knucklehead, they all had an appetite for high viscosity engine oils. I thought back too, and recalled that in my oil company days, Harley shops often preferred to use an SAE 60 aircraft engine oil or SAE 60 racing oil. (In fact, we worried that either of these oils, which dont contain the kinds of performance additive packages found in modern engine oils, would lead to major problems.)

In 1984 Harley made a major advance in design to its so-called Evolution or Evo engine, Dave continued. This was an air-cooled, V-block engine with all-aluminum heads and cylinders for reduced weight. With this design change, the oil requirement also changed to an SAE 20W-50 with API category credentials. The Evo was superseded in 1998 by the Twin Cam or Fathead engine. It, too, was an aluminum design and also had an appetite for SAE 20W-50 API category engine oils.

Looking more closely at the needs of todays motorcycles, I turned next to the Japan Automobile Standards Organization. Its JASO T 903:2011 Implementation Manual has become the essential standard for four-cycle motorcycle engine lubes, with international recognition. Originally issued in 1998 and updated regularly since then, it establishes physical and chemical limits which are similar to but not quite the same as those in the American Petroleum Institutes passenger car engine oil category.

Key areas where JASO and API dont coincide are phosphorus content, volatility and shear stability. In each of these parameters, the JASO limit is quite loose compared to whats typically seen in our gasoline-fueled engine oils. In fact, as you look at these limits (Table 1, at left) they may seem more in line with heavy-duty diesel oil standards, such as API CJ-4.

The JASO standard also requires a unique performance test which measures frictional characteristics of four-cycle engine oils. Once passenger car engine oils began using friction modifiers and lighter viscosities in order to save fuel, JASO members worried that these oils would not meet the needs of motorcycles. The concern is heightened with wet-clutch and gear sets which are integral to the engine and share the same lubricant. Having too much friction-reduction additives in the oil will cause both slippage of the clutch and gear wear and pitting. JASO set up different categories of oil (MA, MA1, MA2 and MB) which are based on the oils performance in this test. The MA categories have varying degrees of frictional performance, while MB has the lowest level of friction modification.

And what about motorcycle two-stroke engine oils? These engine designs require the oil to be mixed with the fuel (often at a 20:1 ratio) and burned in the combustion chamber. Any unburned lubricant is expelled with the exhaust, often spewing high levels of particulate matter and hydrocarbons.

For more insights, I reached out to Ed Callis of Spectrum Oil, the go-to guy for me on this subject. According to Ed, in the world of two-cycle engines for motorcycles, virtually every model now uses lube injection, with a separate oil tank and a pump to meter the oil into the fuel mix. The pump may be either dumb and dispense a constant ratio of oil into a measured amount of fuel, or smart, in which case it is programmed to sense throttle position and RPM and varies the oil-to-fuel ratio accordingly.

As youd expect, JASO has a standard for two-cycle motorcycle oils as well, JASO M345. It includes three categories which are identified as FB, FC and FD. These oils also have specific physical and chemical properties (Table 2).

In addition, there are four engine tests designed to measure critical two-cycle oil properties (Table 3). The first two are run in a 49cc Honda forced-air-cooled scooter engine:

The JASO M340 test measures the oils lubricity (resistance to seizure and scuffing) at a 50:1 fuel-to-oil ratio.

The JASO M341 test, with durations of 60 minutes and 180 minutes, measures oil detergency (ring sticking and resistance to deposits) and is run at 100:1 fuel-to-oil ratio.

JASO M342 and JASO M343 are run in a Suzuki 69cc forced-air-cooled generator engine. The former is run at 10:1 fuel-to-oil and measures the tendency of the oil to create a smoky exhaust. The latter uses a 5:1 fuel-to-oil and measures the oils resistance to carbon formation in the exhaust system.

Many lubricant blenders and marketers who want to play in this field take the extra steps to get their oil listed as a qualified product with JASO. For those of you who are accustomed to the API Engine Oil Licensing and Certification System, one of the interesting aspects of the JASO licensing system for motorcycle oils is that it is entirely a self-certifying scheme. Marketers review the standard, test their motorcycle oil against it, and confirm to JASO that their product meets a specific performance level. After submitting their test data and proper forms to JASO, plus a management fee of Yen 40,000 (about $400) for each submission, the marketer is allowed to cite the relevant JASO standard on its labels.

JASO calls this system on-file and it maintains a list of products that have submitted data showing they meet its standards. And it strongly emphasizes that the oil seller is responsible for guaranteeing the quality and performance of the product – not JASO. In fact, it admonishes submitters not to use advertising, wording or labels that imply that JASO has approved or certified the oils quality and performance, and asks to see a copy of the label so it can check.

The licensing details plus updated lists of on-file JASO motorcycle oils are found at the website of the Japan Lubricating Oil Society, http://www.jalos. or.jp/onfile/. As of Feb. 1, the listings included nearly 500 two-cycle oils and 900 four-cycle oils.

All in all, there is a lot to consider when trying to lubricate a two- or three-wheeler. What kind of engine is it, what vintage, what does the owners manual say, and where to get a reputable oil? Id say that you can count on the brands that have been around for a long time and that have a track record with these beauties. And Id love to ride along – but would need a three-wheeler for sure.

Industry consultant Steve Swedberg has over 40 years experience in lubricants, most notably with Pennzoil and Chevron Oronite. He is a longtime member of the American Chemical Society and SAE International, where he was chairman of Technical Committee 1 on automotive engine oils. He can be reached at steveswedberg@cox.net.