Future of the hexhead

[129654]

I read with interest on another forum (UKGSer.com), speculation with regard to the future of the hexhead. Some over the pond are of the opinion that the current engine won't meet future Euro emission standards. Hopefully this isn't the case as the air cooled hexhead on my GS is what drew me to the brand.

Anyone got any intel on what tricks the BMW engineers have up their sleeve?

[deilenberger]

I think what you're reading is simply Internet (aka "Interweb") speculation based on no facts at all. The hexhead motor isn't air-cooled, it's oil-cooled and the temperature of it is regulated much tighter than a pure air-cooled engine can be, allowing advanced emissions controls to be used. I don't have the numbers, but it wouldn't surprise me to find out that the current Hexhead design meets future regulations, BMW isn't living in a vacuum.. and they have lots of experience in advanced engine design.

[leadfoot]

I think what you're reading is simply Internet (aka "Interweb") speculation based on no facts at all. The hexhead motor isn't air-cooled, it's oil-cooled and the temperature of it is regulated much tighter than a pure air-cooled engine can be, allowing advanced emissions controls to be used. I don't have the numbers, but it wouldn't surprise me to find out that the current Hexhead design meets future regulations, BMW isn't living in a vacuum.. and they have lots of experience in advanced engine design.

+1 on that! Besides, I think that if there was any talk of a major brand not meeting emmissions standars anywhere it would be of Harley Davidson and their air cooled bikes. If HD can meet the requirements, you can bet that BMW can.

[DarrylRi]

There was another thread recently regarding how "green" (or not) motorcycles are. In that thread I took the time to look at BMW's filings with the California Air Resources Board (CARB). California has instituted two tightenings of motorcycle emissions this decade, in 2004 and 2008. The US EPA has picked up these changes, for implementation in 2006 and 2010.

The 2008 CARB rules allow motorcycles to produce about 20 times as much HC (hydrocarbons) and CO (carbon monoxide) as autos. Undoubtedly this is not the end of the emissions restrictions that will be placed on bikes, just steps along the way.

Europe has their own standards, and it appears that they will force the next tightening of emissions restrictions.

When I looked at BMW's filings, I found that the "dirtiest" current model is also the one with the oldest engine design: the K1200LT, which is still using the lazy four K motor. If I recall correctly, it was measured at 0.5 gm/km of HC and CO, or about 10 times what autos are allowed. The cleanest BMWs were the F800s, at about 0.2 gm/km. The hexheads were in between, on the higher side.

Emissions standards are a gradual, evolutionary change. BMW has always been well ahead of the curve with them. I believe that BMW was meeting the 2008 CARB requirements in 2002. But there's no sense in downgrading power and/or drivability without understanding when, and how much, will be required.

[deilenberger]

Just a comment. I attended a BMW open-house at BMW-NA for the BMW Car Club of America last spring.. and the subject of emissions standards came up while talking to some of the product engineers.

The product engineers were very much in favor of emissions standards, and not for simply cleaning up the environment (although I'm sure this was part of the reason..) They made the statement "The performance you have today is the result of tightening emissions and mileage requirements in the past.." and went on to make the point that most of the advanced engine control systems and advanced engine designs are the result of engineering originally done to meet emissions and mileage standards.

If it wasn't for emissions and mileage requirements, I suspect the use of fuel-injection, high-flow engine/exhaust designs, advanced ignition control would be the exception, not the norm. And I think (from what the engineer said) the systems would be much less advanced then they are now.

BMW - at least on the car side - sees tightening emissions and mileage standards as an opportunity, not as a burden. Hopefully some other motorcycle companies think the same way, if so - we'll all benefit.

[danalbertson]

+1 on that! Besides, I think that if there was any talk of a major brand not meeting emmissions standars anywhere it would be of Harley Davidson and their air cooled bikes. If HD can meet the requirements, you can bet that BMW can.

Since you mentioned HD, I have heard it said the HD air cooled motor may be on borrowed time. Perhaps the frame redesign of the baggers for 2009 is to accommodate a radiator in 2011?

I hope the Hex Head does not get water cooled either.

[129654]

I hope the Hex Head does not get water cooled either.

My concern too!

[AZgman]

I also think the possible change to an overhead cam is of concern. For me, 110 hp is enough and coupled with the simplicity of the current valve train design, trumps a bump up to 120 or 125hp that is tied to the complexity of adjusting an overhead cam engine. (I owned a K1200LT in the past!)

[Polarbear]

Heck, I think 75-85 HP is more than enough for me and I really enjoyed my past bikes in that HP category:). My current GSA at 100 is overkill in HP. We also have a new KLR650'08 at 42+ HP and its equally fun to ride? HP is a mentality of many many riders, I know and I've never understood it. As for the EPA, they should be abolished! I've never been a fan of this org....We most probably would still be where we are today,without this beaurocracy, because we love saving our money and better, cleaner running vehicles do this. Many engineered gasoline saving ideas have come and gone, due to red tape,etc.. The 100 mpg carb was one, remember? It existed and was shot down! Reason??? We "have" clean air, without the EPA muddling it all up, I say:). I know this will rattle many enviro nuts, but its my opinion out there:). Happy Trails, Randy.....PS;I voted for Nixon then, but the EPA was his baby and a really dumb idea in retrospect. Sorry for the politics entre....:thumb :usa

[amiles]

The future of the hexhead will be limited by the ongoing race for displacement.
Let's face it, the majority of the riders - all riders, except the repli-racer crowd - considers a 1200cc bike a small bike. The boxer ,as we know it, has its limitations as far as size is concerned. This, not emissions may kill the hexhead, if customer perception won't change.

I am apparently a luddite in more ways than one, I just don't see the need for a modern touring type motorcycle to have an engine displacement in excess of 1200 cc or so. What with the generous power output available via the computer controlled ignition and fuel systems I just don't see it. A lean and mean high performance BMW has an appeal all it's own. Long distances well planned trips and a willing and able steed!

Of course the term "practical" does not mesh well with an object carrying emotional aspects as strongly as a motorcycle.

[hlothery]

Since you mentioned HD, I have heard it said the HD air cooled motor may be on borrowed time. Perhaps the frame redesign of the baggers for 2009 is to accommodate a radiator in 2011?

I hope the Hex Head does not get water cooled either.

As a former HD owner (2003 Anniversary Road King) I know this is true. Delphi was constantly stiving to maintain emmision standards in an engine designed for potato-potato. I think this was the driving force behind the collaboration with Porsche on the V-Rod. I would, personally, love to have a Road King with the V-Rod engine. Interestingly, my Road King was one of few that were fuel injected....an innovation rejected by old line HD owners. Porsche, the bastion of boxer innovation (IMHO) finally succombed to liquid cooling. I suspect all will eventually.

[sjbmw]

There was a lot of blogging about the end of the boxer motor before the hexhead was introduced. Displacement was maxed out at under 100hp, could go no further, outdated design that had run its course, etc.

Then, along comes the 1200 GS all that blew up, in a hail of dust.

HD desperately wants the VRod motor across it's entire big bore model line, but the old schoolers are hesitant, and ergo, so is management.

[deilenberger]

I also think the possible change to an overhead cam is of concern. For me, 110 hp is enough and coupled with the simplicity of the current valve train design, trumps a bump up to 120 or 125hp that is tied to the complexity of adjusting an overhead cam engine. (I owned a K1200LT in the past!)Actually - aside from having to purchase the shim kit.. I think it would be an easier adjustment.

The overhead cam design in the HP2 performance engine is almost identical to the design BMW used on the S54 M-series car engines (and was derived from F1 engines.) Big plus to the design - much like the lazy-K-bike engine, the adjustment intervals are MUCH longer than the current Hexhead engine. On my M3 - adjustment is done every "Inspection" service - which works out to around 30-40,000 miles (exact time is dependent on how hard I drive it.)

It's also a low friction design, using the finger to translate rotary-eccentric motion from the cam into up/down motion for the valve stem - which avoids side-loading put on the valve stem and should lessen valve guide wear (and related power losses.)

To change the shim on "top" of the valve (actually sticking out at you on a Hexhead) - you simply move the rocking finger aside after removing the small metal bracket that keeps it from moving sideways. You then use a small magnetic tool to plug the shim from the top of the valve stem (same tool is used to install the new shim.) You measure the shim - and determine what size is needed to set the correct gap.

Based on K bike experience - if this design needs adjustment more than a few times in the life of the bike I'd be quite surprised.

I don't see the downside to it.. and if it was offered when I bought the R1200R I would have enthusiastically embraced it.

[deilenberger]

Since you mentioned HD, I have heard it said the HD air cooled motor may be on borrowed time. Perhaps the frame redesign of the baggers for 2009 is to accommodate a radiator in 2011?

I hope the Hex Head does not get water cooled either.It's already OIL cooled, there is no reason for water cooling for emissions purposes (there is an advantage to a full cylinder water jacket for noise suppression with water cooling.)

I don't see it happening (water cooling a new boxer engine.)

[deilenberger]

The 100 mpg carb was one, remember? It existed and was shot down!Umm... got any links or details to that? Was it compatible with the water-to-gasoline-pill that I think was shipping around the same time? :dance

[108625]

I remember an in depth article in Cycle world several years ago about BMW developing a water cooled, overhead cam boxer engine for racing. There were even pics of a test-mule bike on the track. The whole project was shelved due to a rare flash of common sense; the aerodynamic penaties of sticking cylinders out in the wind (for no useful purpose on a water cooled engine) were too great for the bike to be competitive.

BMW builds boxer engines (and shaft drives) because there is still enough of a demand for them amongst traditionalists to justify the effort. However, there is not enough of a growing demand for them to let all their motorcycle business live or die based on that one engine layout.
Building water cooled fours, twins and singles (with shaft, chain and belt drives) appeals to a larger, younger market. It is also probably more cost effective: from an R&D standpoint (water cooled, overhead cam engines share a lot more traits amongst themselves and with car engines as well, as compared to an air & oil cooled pushrod twin), and from a cost of manufacture standpoint (there's a lot less machining and assembly involved when all the cylinders are in the same block, and integral with the crankcase).
That shaft driven-boxer buying "traditionalist" demographic is getting older by the way, not encouraging for long term future sales. I don't think emissions laws will kill the hexhead (or it's replacement). It will be the bean counters, when they're convinced the target market and profit level is no longer large enough to justify the expense.

I'll miss them when they're gone, but I'll bet the cooling fins on Harleys will be fake before it happens to Beemers and Guzzis.

[k75s]

I think current motorcycle engine displacement/HP/performance can be compared to current computer processor performance. It just doesn't matter any more except for special applications.

Most of us can ride to all ends of the earth with the current range of BMW's displacement, 650 through 1200 (OK, 1300 now).

And I doubt many of you are waiting on your computer to process an instruction anymore.

(Seems like most of my computer software these days is for fending off outside attacks :( )

[AZgman]

Actually - aside from having to purchase the shim kit.. I think it would be an easier adjustment.

The overhead cam design in the HP2 performance engine is almost identical to the design BMW used on the S54 M-series car engines (and was derived from F1 engines.) Big plus to the design - much like the lazy-K-bike engine, the adjustment intervals are MUCH longer than the current Hexhead engine. On my M3 - adjustment is done every "Inspection" service - which works out to around 30-40,000 miles (exact time is dependent on how hard I drive it.)

It's also a low friction design, using the finger to translate rotary-eccentric motion from the cam into up/down motion for the valve stem - which avoids side-loading put on the valve stem and should lessen valve guide wear (and related power losses.)

To change the shim on "top" of the valve (actually sticking out at you on a Hexhead) - you simply move the rocking finger aside after removing the small metal bracket that keeps it from moving sideways. You then use a small magnetic tool to plug the shim from the top of the valve stem (same tool is used to install the new shim.) You measure the shim - and determine what size is needed to set the correct gap.

Based on K bike experience - if this design needs adjustment more than a few times in the life of the bike I'd be quite surprised.

I don't see the downside to it.. and if it was offered when I bought the R1200R I would have enthusiastically embraced it.

I guess we just see this differently. I would agree that I had to adjust the K1200 valves less often, but it was a major PITA! The R1200 valve adjustment is a non-event. If the new OC design is truly much easier to inspect and adjust than the K1200 was, then I guess you could make a believer out of me, but I'm "from Missouri" on this one!

[deilenberger]

I guess we just see this differently. I would agree that I had to adjust the K1200 valves less often, but it was a major PITA! The R1200 valve adjustment is a non-event. If the new OC design is truly much easier to inspect and adjust than the K1200 was, then I guess you could make a believer out of me, but I'm "from Missouri" on this one!Let's go through the differences..


K1200 - lots of plastic to remove (PITA..)
R1200 - no plastic, heads hanging in the breeze (NO-PITA)
K1200 - have to pull the camshafts to change the adjusting buckets (MAJOR-PITA)
R1200 - have to slide a finger over so the shim can be R&R'd (NO-PITA, actually easier than loosening, tweeking, tightening, redoing until right the current adjustment on R12 engines..)

Measuring the clearances is the same no matter what design you have..

A fer'instance - my M3 engine has 24 valves. Once I get TO the valves (all the crap I have to R&R to get the valve cover off) it takes about 45 minutes to check and adjust the one or two that need adjustment. This is done every 30-40k miles. An R1200 engine, using the same side, getting to the valves might take 10 minutes (remove plug, remove valve cover) and then we have 8/24ths as much work to do.. (1/3rd) so 45/3.33=mebbe 15 minutes to do the valves. About the same or less than it takes me now to do my R1200R valves.

Including lily-gilding (unnecessary polishing and cleaning), bet I'd be out of there within an hour..

[TGA57589]

I enjoy reading the brainstorming of fellow BMW owners in what I have read in this column. I think what has come to the surface is this: when you break down whatever engine design it is be it a Briggs and Stratton Boxer or any gasoline engine it is engine management that has moved all of them to what we have today. I tell people about my R1200RT that it's just a tractor motor and laugh a bit. What is so interesting is how most all engines have adavnced with controls managing air flow, fuel metering, timing, and the list goes on and on. I worked on many race cars mostly dirt high dollar engines of around $40 k in the early 90's. What inspired some of the engines in passenger cars was racing crank triggers for timing, good fuel management, exhaust temperature, intake temperature etc. I could go on and on but it made me think what you guys were talking about is of our Boxer motor and what has made it such a bullet proof piece that was once more or less a "tractor motor" Excuse me if my thoughts are a bit random but I don't think the Boxer is going to go away any time real soon as they got something that is a proven powerplant.

[TomfromMD]

Umm... got any links or details to that? {100 mpg carb} Was it compatible with the water-to-gasoline-pill that I think was shipping around the same time? :dance
I'm planning to fit a couple to my '06RT, just as soon as my $10,000,000.00 comes in from Nigeria.:)
Tom