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Old 09-03-2012, 11:46 AM   #2116
FlyingFinn
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Quote:
Originally Posted by rdcyclist View Post
The prime reason for the Boxer engine is perfect primary harmonic balance. For a given displacement, an inline configuration cannot approach the smoothness of the Boxer.
You have mastered the art of sarcasm.

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Old 09-03-2012, 12:04 PM   #2117
Marki_GSA
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Quote:
Originally Posted by rdcyclist View Post
The prime reason for the Boxer engine is perfect primary harmonic balance. For a given displacement, an inline configuration cannot approach the smoothness of the Boxer. This is why Porsche, Subaru and most light aircraft engines are Boxer Configuration. In the case of the light aircraft, there is the small matter of FAA certification and difficulty of obtaining said cert...
Your absolutely right in theory right up until you add ignition. If they had fired both pots at the same time or a 4 cylinder boxer you get a smooth engine. What we have just now though is far from smooth. I have seen Harley's vibrate less than a BMW boxer.
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Old 09-03-2012, 01:20 PM   #2118
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Quote:
Originally Posted by Marki_GSA View Post
I have seen Harley's vibrate less than a BMW boxer.
Assuming that the engine was not running, I suppose.

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Old 09-03-2012, 01:42 PM   #2119
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Old 09-03-2012, 01:51 PM   #2120
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Old 09-03-2012, 03:21 PM   #2121
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I hafta say, that first pic looks really great! Almost makes me want to hold off getting a '13 GSA and wait for the WC GSA's to come out - almost...

OTOH, being a beta tester sucks bigtime!!

Beemerlover screwed with this post 09-03-2012 at 03:28 PM
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Old 09-03-2012, 03:23 PM   #2122
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2 cylinder boxers aren't that smooth.

Obviously the balance on the BMW boxer isn't that good or there would have been no need for BMW to add that single balance shaft to the 1200 hexhead or camhead.

The balance on the 6 cylinder boxer is excellent with some of the pistons always in motion and very little rocking couple.

The balance on the 4 cylinder boxer is OK but now some rocking couple enters and more 2nd order as there are points where all the pistons stop completely at the same time.

The balance on the 360 2 cylinder boxers leave a lot to be desired, especially on large cylinder configurations, as the pistons are not directly across from each other due to being on different crank throws with an offset between rod centers. 2 cylinder 360 boxers also have both pistons completely stop and change direction twice per revolution. Lots of higher RPM buzz and rocking couple excitement.

The C/G on the BMW 2 cylinder boxer isn't all that great either as it has a deep wet sump so the crankshaft is high in the crankcase. The crank must also be high to keep the cylinder heads from dragging the ground in turns. That heavy alternator is also way up high way off the engine roll center. The transmission input shaft is high with the counter shaft not much lower.
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Old 09-03-2012, 03:31 PM   #2123
def
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Quote:
Originally Posted by slipknot View Post
The boxer advantages, with or without water:

Lower center of gravity

Easy access for service or repairs

Best foot protection in an accident: this is backed up by studies by Hurt and others.



What I think is a negative with the new design, if I'm not mistaken on the design having not studied it, is the sharing of engine oil with the clutch and transmission. There are advantages to having them separate. I also like the single plate dry clutch, very light to work all day and fewer parts to replace.

Or course a wet clutch can take more abuse but abusing a clutch was not a popular thing to do until ADV made abuse of fine machines obligatory for attaining manhood.
Typical inline motorcycle engine/transmission designs have employed shared engine oil successfully for years without problems. Also, as you point out, the wet clutch usually has longevity over the current boxer dry clutch design. Hopefully, the water cooled boxer will employ a simplified transmission design that eliminates the weak transmission input spline design while increasing reliability in this area. The only concerns with the shared oil designs is the shearing of the oil by the transmission to a lower viscosity that leaves the engine bearings vulnerable. Synthetics can help relieve the shearing.

The water cooled boxer will provide a much quieter engine and transmsion and provide a new platform for increased power and performance.

Finally, from the photos I have seen of the water boxer, the exhaust system bends and complexity could be reduced significantly providing a cleaner look, lower weight and less heat.
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Old 09-03-2012, 05:16 PM   #2124
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Do we have any indication the Wasser boxer will be lighter than the current GS?
Lower center of gravity?

Clearly the power output will be high (130Hp)...but will the torque be better.
The torque of the cam head is NOT especially good for an enging of it displacement...and it does rev high to get the HP
Note the F800 engine has nearly 90% of the 1200 torgue with on 50% of it's displacement!
Hopefully the torque will be MUCH better in the wasser boxer.

Any better info?
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Old 09-03-2012, 07:02 PM   #2125
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Looks like no more x spoke wheels. Tubeless design similar to Yamaha....good move.

Joe




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Old 09-03-2012, 07:14 PM   #2126
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Quote:
Originally Posted by JStancampiano View Post
Looks like no more x spoke wheels. Tubeless design similar to Yamaha....good move.

Joe
The BMW GS cross spoke wheels have been tubeless since the mid 90's.
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Old 09-03-2012, 08:00 PM   #2127
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Quote:
Originally Posted by vtbob View Post
The torque of the cam head is NOT especially good for an enging of it displacement...and it does rev high to get the HP
Note the F800 engine has nearly 90% of the 1200 torgue with on 50% of it's displacement!
Hopefully the torque will be MUCH better in the wasser boxer.

Can you clarify? The current GS makes 88 ft lbs and was / is enhanced by the exhaust flapper for lower torque delivery. Given, it's not a 'smooth' curve by dyno standards, it works very well in the real world.

Could you reference other bikes in that displacement which have better torque and curves?

Also, you note that the 800GS makes 90% of the 1200GS' torque at 50% its displacement? Last I checked, 50% of 1200 equals 600cc.
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Old 09-03-2012, 08:17 PM   #2128
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Quote:
Originally Posted by vtbob View Post
Do we have any indication the Wasser boxer will be lighter than the current GS?
Lower center of gravity?

Clearly the power output will be high (130Hp)...but will the torque be better.
The torque of the cam head is NOT especially good for an enging of it displacement...and it does rev high to get the HP
Note the F800 engine has nearly 90% of the 1200 torgue with on 50% of it's displacement!
Hopefully the torque will be MUCH better in the wasser boxer.

Any better info?
Fact check:

F800GS has 61 lb/ft of torque
R1200GS has 89 lb/ft of torque

Therefore R1200GS has 46% more torque than an F800GS or in your comparison, F800 has 68.5% of the torque of the 1200, not 90% and 67% of the displacement.

But but the 1200 is a tank you might say, right. 516 vs 472 wet...that's less than 10% added weight for those sexy boxer pots.

10% more weight, 46% more torque...I'll take those numbers any day and I did :-)

Source 2012 models on BMW USA website
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Old 09-03-2012, 09:02 PM   #2129
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Quote:
Originally Posted by EJ_92606 View Post
Fact check:

F800GS has 61 lb/ft of torque
R1200GS has 89 lb/ft of torque

Therefore R1200GS has 46% more torque than an F800GS or in your comparison, F800 has 68.5% of the torque of the 1200, not 90% and 67% of the displacement.

But but the 1200 is a tank you might say, right. 516 vs 472 wet...that's less than 10% added weight for those sexy boxer pots.

10% more weight, 46% more torque...I'll take those numbers any day and I did :-)

Source 2012 models on BMW USA website
Exactly. I almost wonder about need the F800 fills. It's not much lighter, no where near as powerful, more vibration, doesn't get enough better mileage to justify the lack of power and it's not THAT much cheaper. I don't get it...but that's just me and I'm a bit different...
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Old 09-03-2012, 09:06 PM   #2130
rdcyclist
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Quote:
Originally Posted by ytsiwt View Post
2 cylinder boxers aren't that smooth.

Obviously the balance on the BMW boxer isn't that good or there would have been no need for BMW to add that single balance shaft to the 1200 hexhead or camhead.

[edit]
The primary reason for the secondary shaft is to reduce the torque effect of the inline crankshaft. The shaft was left out of the HP2's and the difference in smoothness between the two is negligible. The torque effect difference is NOT negligible...
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