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Old 02-07-2012, 03:01 PM   #1501
Beemerlover
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Originally Posted by marchyman View Post
I didn't think about that. Or, to be more accurate, I didn't think.

How often do you need access to the piston on a modern boxer? I'm aware of one where the piston disintegrated at 180K miles. The solution to that problem was a salvage engine that was only 25K miles old. Much cheaper than trying to fix the old engine.



What oil pan?

So, are the cams only supported right in the middle with the ends sticking out into space? Maybe I'm missing something, but that pic doesn't look right. Also, I wonder what that big boss on the outside-center of the head with the hole in it is for?
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Old 02-07-2012, 04:08 PM   #1502
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So, are the cams only supported right in the middle with the ends sticking out into space? Maybe I'm missing something, but that pic doesn't look right. Also, I wonder what that big boss on the outside-center of the head with the hole in it is for?


Looks pretty much how the cams are supported in the current camhead motors. The boss on the the outside edge of the head - possibly to mount the shaft for the cam drive gear? - yes I think I saw gear driven cams mentioned somewhere.
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Old 02-07-2012, 04:45 PM   #1503
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Originally Posted by jtfbb View Post
Looks pretty much how the cams are supported in the current camhead motors. The boss on the the outside edge of the head - possibly to mount the shaft for the cam drive gear? - yes I think I saw gear driven cams mentioned somewhere.
From the pics I've seen of the camhead heads, there appears to be two fairly widely-spaced bearings for the cams. This pick looks like the only bearings are right in the middle. Maybe it's just the angle of the pics though.

Gear drive for the cams huh? Sounds like a good idea, but I wonder if that will be a chain-driven gear in the heads that couples to gears on the ends of the cams? Guess time will tell.
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Old 02-07-2012, 06:54 PM   #1504
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Originally Posted by Marki_GSA View Post
There has to be some access otherwise you wouldn't be a able to build the engine in the first place. Of course they could be 3D printing them. ;)
This is educated conjecture at its best, but the design looks like a wet liner design. It's likely that the block is assembled with the rods attached to the crankshaft. The pistons would then be installed into the bores of the liners. With the pistons protruding from the bottom of the liners the piston wrist pins would then pushed through the pistons and into the upper rod bores via an access hole made available through a water pipe flange, or some such, on either cylinder when the pistons are joined with the rods.

This type of design was used by VW on the Wasser Boxer Vanagon for many years. IIRC, Renault was also fond of this design. A major drawback of this design is that removing the piston pins after many miles/years of use is difficult when there are some carbon deposits on the exposed portions of the wrist pins between the upper rod journals and the piston wrist pin bosses. Special tools are usually required to facilitate pin removal. Neanderthal measures and home mechanic clubbings don't work here. An owner of this type of engine design must not neglect or lengthen oil change intervals and must not use inferior dino oil.

Another drawback of this type of design is that the o-rings at the top and bottom of the liners are also sensitive to poor maintenance. The coolant must not be allowed to degrade enough to allow corrosion of the grooves that hold the o-rings. Without proper maintenance, the o-ring grooves degrade and cause the o-rings to fail if the liners are made of iron that is exposed to the coolant. This would likely allow water into the crankcase and its oil if the liners aren't coated to protect the iron in the liners or the liners are not made of non-corrosive materials. Electrolysis is the enemy here.

The rear view of the block doesn't show any access ports, water pumps or flanges that might provide wrist pin access. I would bet that a frontal view of the block would provide evidence of properly positioned devices that allow access to the wrist pins. Such a view would solidify the idea that these engines are a wet liner design.

This is my take after rebuilding many Vanagons and is subject to withdrawal after serious internet flaming or real proof otherwise avails itself.

As ever, YMMV.
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Old 02-08-2012, 07:15 AM   #1505
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99% sure it is a wet clutch and the FD unit is the same as used on the new K1600's, a much more robust unit.
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Old 02-08-2012, 08:24 AM   #1506
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Originally Posted by Beemerlover View Post
Probably off-subject, but do those guys in the pics REALLY need those knee sliders with boxes mounted on those bikes?
Knee pucks are not used for support, they are used as a lean angle gauge. If the guys know how far to lean and hang so that the pucks touch just before the boxes, they'd be helpful.
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Old 02-08-2012, 10:38 AM   #1507
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Originally Posted by Deans BMW View Post
99% sure it is a wet clutch and the FD unit is the same as used on the new K1600's, a much more robust unit.
Is the K1600GT final drive a significantly different design internally? Or just more robust? I just hope the new FD is lighter as I think the single worst design element of my GSA is the amount of unsprung weight at the rear wheel. It's very obvious when driving over bumpy surfaces....

g-
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Old 02-08-2012, 03:07 PM   #1508
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Originally Posted by g_e_young View Post
Is the K1600GT final drive a significantly different design internally? Or just more robust? I just hope the new FD is lighter as I think the single worst design element of my GSA is the amount of unsprung weight at the rear wheel. It's very obvious when driving over bumpy surfaces....

g-
Both a different internal design and more robust.
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Old 02-08-2012, 09:22 PM   #1509
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Originally Posted by g_e_young View Post
Is the K1600GT final drive a significantly different design internally? Or just more robust? I just hope the new FD is lighter as I think the single worst design element of my GSA is the amount of unsprung weight at the rear wheel. It's very obvious when driving over bumpy surfaces....

g-
Did you try with a better rear shock? While I am not saying it reduces the unsprung weight, it does reduce the rear wheel trampling.
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Old 02-09-2012, 04:03 AM   #1510
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Originally Posted by PeterW View Post
Hopefully they actually re-engineered that final drive as well - rather than just continuing to push more ponies through something that was marginal 10 years ago :)

The GS is a great bike, one I've always lusted after, IF you can overlook the reliability issues - I can't.

Pete

Thats a big HELL YEAH! I am in the position now to own a GSA but will go with the Tenere or Tiger 1200. Def the Yamaha Tenere 1200. I absolutely love the BMW GSA. It looks the part...it just looks so trick compared to the other bikes in the adv segment but I hate being stranded. I tend to get far away from civilazation so dependability is the absolute most important thing for me. Thats why I choose Japan motorcycles. Oh, as you guys probably can figure, i ride a Strom.
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Old 02-09-2012, 04:24 AM   #1511
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I would like to know why BMW needs to make a adv bike with 130hp???
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Old 02-09-2012, 04:55 AM   #1512
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Originally Posted by Deans BMW View Post
Both a different internal design and more robust.
Can you go into any detail on why you believe this? I'm not trying to sound argumentative, but it is what we all want to hear, and what BMW must know we all want to hear, so I tend to be somewhat skeptical when statements like that come along.
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Old 02-09-2012, 05:20 AM   #1513
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Originally Posted by whittrated03 View Post
Thats a big HELL YEAH! I am in the position now to own a GSA but will go with the Tenere or Tiger 1200. Def the Yamaha Tenere 1200. I absolutely love the BMW GSA. It looks the part...it just looks so trick compared to the other bikes in the adv segment but I hate being stranded. I tend to get far away from civilazation so dependability is the absolute most important thing for me. Thats why I choose Japan motorcycles. Oh, as you guys probably can figure, i ride a Strom.
Obviously you really want a BMW though, or you wouldn't be here!

Jim
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Old 02-09-2012, 05:53 AM   #1514
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Originally Posted by whittrated03 View Post
I would like to know why BMW needs to make a adv bike with 130hp???
Kinda my take too. Unless they feel really compelled to chase the Multistrada into a segment that isn't 'GS'. The 'upright sport touring bike' segment. Maybe it'll get a 17" front too!
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Old 02-09-2012, 06:07 AM   #1515
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Talking

Sorry, Jim, but that argument is rather weak!

For anyone with a general interest in motorcycling & adventure-riding [and keyboard time!!!] the G-Spot sites are relatively attractive . . . it's not just all the Angst and hurly-burly . . . it's the sheer accessibility of the layout of "threads with titles".
Unless you are a committed close-follower of one of the mega-threads of "Beasts" (or whatever) . . . it is difficult to keep in touch with what is happening there . . . yes, it is actually a bit daunting to find a thread with 2,000 or 20,000 posts sitting there . . . like a nightmare of unread emails.

(Have to put in a good word for "Hacks", in the same way )
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