BMW R20 Concept Shown

[kbasa]

I agree, but he was basing his belief solely on size, they couldn’t make the heads bigger because of size limitations. I haven’t done any engine comparisons, so what was the solving of the problem, do the heads sit higher in the engine and frame? Or was he just making **** up?

If you think about trying to operate a 1000cc single in the framework of emissions, it can be tough or was 15 or 20 years ago. That’s a lot of cylinder volume to get to burn cleanly. Flame front development for BMW started with the twin spark Spork motors in like 2002 and has been part of hex and water boxers since. I’d expect that was part of the reasoning back then: emissions. Engine controls have come a long way since.

Note that the R18/20 is a pushrod motor with the cam on top like a /2. That lets it be narrower without cams living in the heads. With the cam on above the crankshaft, they can raise the motor in the chassis while keeping the crank aligned with the bike’s roll axis.

It’d be interesting to get a front view of the R20 and take a measurement to see what lean angle it will tolerate. I bet it’s more than anyone would regularly use in street riding.

 

[PGlaves]

I agree, but he was basing his belief solely on size, they couldn’t make the heads bigger because of size limitations. I haven’t done any engine comparisons, so what was the solving of the problem, do the heads sit higher in the engine and frame? Or was he just making **** up?

I think the size issue was at least partly solved with liquid cooling. The head can be more compact when it doesn't need the fins for cooling.

 

[r0ckrat]

On the 1300 they also moved the crank a little higher, tucking the transmission underneath (and I think it now has a longer driveshaft as well.) For the right cylinder they flipped which side the cam gear is on (same ports, cam chain in front on right, back on left.) This also makes the cylinder structures mostly symmetrical, providing yet more room for the rider's feet. Improvements in manufacturing accuracy, computer design, modelling, and testing means tolerances can be tighter and parts can be made smaller with the same strength (or less over-built in some applications) so some things can be made that are lighter, smaller, and do things not imagined possible before. High-accuracy computer controls and sensors, and the continuing miniaturization of electronics, require much less space than older items (new injectors are TEENY compared to previous iterations, not to mention coil packs, air flow sensors, brake pumps, etc.)

All of these together allow for the creation of a larger displacement engine that still allows it to be horizontally opposed with (I assume from talking to a few new GS owners) even better riding characteristics than previous iterations.

 

[smswy]

Where do you attach the aluminum panniers?

 

[bc1100s]

Where do you attach the aluminum panniers?

See Post #3 on page 1 of this thread.