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Understanding terminolgy


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I'll help.

My 1980 R100 RT had an oil cooler.

But it is an airhead.


Dependsing on where in the world, around '93 oil coolers were added, model by model over time.

These are oilheads, usually ridden by Airheads.

The other iterations reflect design changes to bring us further from the era of Airheads, which is the time BMW developed a reputation for quality, simplicity, dependability.

Since then BMW have become more powerful, have better suspension

(tele/duo lever among them), gotten heavier, more complicated (like most things, me included), and developed a polarizing reputation for quality and dependability.

I left the Airhead world in 2005 when I sold my R100 RT, then

the oilhead RSL and went to the Dark Side.

So I figure I'm just an Airhead flying a brick.

Best wishes.


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There have been three shifts in how BMW cools the top end of the boxer engines found in RT's, R's, GS's, etc.


Air cooled i.e. were cooled by air up to 1998 I think...give or take a year.


Then BMW begin to add oil cooling to the top end creating the age of oil heads. Oil heads also had some other physical changes along the way with the heads and valve train, but were still oil cooled i.e. hexhead, camhead


Then in 2013 they added water to the boxer sometimes called water boxer, wethead, and LC for liquid cooled. The LC debuted in the GS Boxer in 2013 and added to the RT in 2014.


I am sure others will correct with dates and add lots more technical info, but that is primarily the designation of the boxer family. Such things as dual spark came in when they went from 1 spark plug to 2 spark plugs per cylinder.

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I am new to the BMW world. Trying to sort thru the shorthand '

Oilhead ?

"Hexhead ?






BMW Boxers that are strictly air cooled (regardless of whether or not they had an oil cooler to cool the oil), are known as Airheads. Airheads, technically, go all the way back to the 1923 R32 boxer twin. I believe we can safely include the R25/26 singles as Airheads as well.


While BMW continued with the Airheads in some models into 1995, in 1994 they introduced the air/oil cooled motor on the R1100RS. While this motor also had an oil cooler, the motor differed because any cooling that the oil provided the cylinder head was not a byproduct of the oil being there for lubrication. It was also deliberately routed up there for cooling. Thus, those motors are referred to as Oilheads. Oilheads came in 1100cc and 1150cc designations thru 2004, although due to a production delay on the Hexhead RT's, there are a few Oilhead RT's out there that carry a 2005 designation, though they're for all intents and purposes a straight continuation of the 2004 production run. In Europe there are 850cc versions, mostly to duck under licensing/registration restrictions. A few of these smaller Oilhead bikes have trickled over here. And there was the R1200C cruiser, which was an Oilhead and 1200cc, but probably more for marketing purposes than performance. Confused yet?

1. Oilhead introduced in '94 on the R1100RS

2. Oilhead motor uses motor oil for more than lubrication, it specifically routes larger volumes of it to the cylinder heads for added cooling.

3. In the U.S., Oilheads were 1100cc and eventually 1150cc in displacement (starting around 2001-GS and 2002-RT).

4. We also got the oddball R1200C cruiser back when BMW thought they were going to compete with Harley-Davidson.

5. Globally, Oilheads are also available in 850cc displacement for a variety of regulatory reasons.


The Hexhead motor was a continuation of the Oilhead, but with several technical changes as well as a hexagonal valve cover. Hexheads started the 1200cc Boxer displacement era. The first was in the 2004 R1200GS, followed by the RT in 2005.


The Camhead motor's exact intro date I'm not sure of, but I think it was 2009. In this motor, the cam was moved up in the cylinder head and, while not an OHC design, it utilized much shorter pushrods which helped reduce reciprocating weight and along with other minor changes delivered a slightly freer-revving motor.


The Wethead refers to BMW's recent liquid-cooled motors, starting with the 2013 GS and the 2014RT and 2014 GS ADV. These motors, while still boxers, are a radical redesign for BMW in that they now sport a wet clutch and are much more compact and powerful than previous boxers.


Any way, I think I got that right. If not, someone will correct me.

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