Exhausts and Engine » New R1250 engine

https://youtu.be/6fiNULAYIUI

The shift cam obviously refers to the shift drum appearance at the end of the cam. But I've watched this a few times and am trying to understand what keeps the cam in position once it has "shifted" over.

Kept in position by solenoids driving the pins, activated by throttle position.
https://www.cycleworld.com/bmw-adopts-va...-adventure-bike

I see how they engage the drum slots and re position the cams, but once in the new position the pins retract. Seems like they would float back and forth without the pins engaged. I'm a little slow like that

I like the idea and simplicity of the Gixxer setup. Although there's no alternate profiles.
https://youtu.be/zbWEUVAQfZ0

Well, is sure isn't Vanos as I thought it would be. The Vanos system does not shift the cam sideways, it rotated the inlet cam. The solution for the boxer does a lot more on the inlet side. The exhaust side is unaffected. The bike system alters lift, comparative lift between the 2 inlet valves, overall duration, opening and closing time and general profile of the cam.
It is also compact because it relies on the computer "brain", and does not take "analogue" readings from the motor, such as oil pressure, which I think Vanos uses.
I suppose the system works on the Boxer as it is effectively a single cylinder motor and there will be that time where the cam is "unloaded" and both inlets are away from contact with the cam. If there were 2 cylinders sharing the same cam, it would be difficult to get the cam into an unloaded condition.
I think it is clever.
Whether the cams designed for the GS will be suitable for the RT, or the RS really depend on how much of a difference is engineered into them as between the models. It may be that the GS design will be fine for the street. Time will tell.

Looks like the RT has been given this new engine for 2019IMG_1290.PNG - Bild entfernt (keine Rechte)

Ah, here's an illustration that points out something not highlighted previously. A "locking bearing" which appears to hold the cams in place after the shift
https://newatlas.com/bmw-motorrad-2019-r.../56374/#p536249

Well, the new models certainly have a lot of color options. However, I struggle to find one that I like very much. Also, for some reason, all of those new 1250 bikes look heavy to me. I sure hope they are not as heavy as they look.

I like the design BMW has chosen for the valves, I think it's a good idea. We should know pretty soon how well it works out in the hands of us normal riders. It looks like the RT does not get the TFT display, instead, it has an RS type digital section. In a way, I am glad the kinks will be worked out on the GS and the RT by the time it gets to the RS.

Here is the latest 2019 GS/RT news from motorcycle.com: http://www.motorcycle.com/mini-features/...-announced.html
The article includes a cutaway of the engine, which has some interesting internal modifications from the 1200 series.

Zitat von Richard230 im Beitrag #9

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Well, the new models certainly have a lot of color options. However, I struggle to find one that I like very much. Also, for some reason, all of those new 1250 bikes look heavy to me. I sure hope they are not as heavy as they look.

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I always thought it was odd the headers on the R1200 liquid cooled engine went so far forward before turning back.
I like how the R1250 headers make a more direct route to the muffler.

091718-P90322842-2019-BMW-R1250GS.jpg - Bild entfernt (keine Rechte)

Did you notice that the new engines use a HiVo type toothed-drive system for the cam shafts? This type of chain was used by the Japanese on some of their motorcycles during the late 1970's and early 1980's. It was supposed to be very reliable. I always wondered why they dropped that sort of chain and returned to a roller chain to drive the cams and clutches. Cost, perhaps?

I also found it interesting that the new engines have two knock sensors so that they can use fuel with octane below 91 in the U.S. and 95 RON, elsewhere. Like the RS already does?

Zitat von Lee im Beitrag #13

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I always thought it was odd the headers on the R1200 liquid cooled engine went so far forward before turning back.
I like how the R1250 headers make a more direct route to the muffler.

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