Leaked Video Reveals 2019 BMW R1250GS "Shift Cam" VVT System
UPDATE: the leaked video has been taken down, but the news is now official, as BMW has announced the Shift Cam system for the 2019 R1250GS and R1250RT. We expect they’ll be joined by the R1250GS Adventrue, R1250R and R1250RS at Intermot.
Leakers are everywhere! In what appears to be an official BMW video, we learn all about the new variable valve technology in BMW’s latest iteration of its classic boxer opposed-Twin. “Shift Cam” is embossed right on the valve covers of the new R1250 engine, and inside them it consists of a shifter-drum type mechanism that has the intake cam moving fore and aft in its journals to shift between two different intake cam lobes: one set of lobes with reduced lift and shorter duration for optimum low-rpm performance, the other for maximum lift and duration for best WOT power production. Exhaust valves will soldier on with just one lobe each.
Also, what the video refers to as “differently opened inlet valves for optimum combustion” means that one intake valve in each head opens and closes slightly before the other one, which has us reminiscing about Suzuki’s old-timey Twin Swirl Combustion Chambers… the results, BMW says in the vid, are “souvereign acceleration and impressive elasticity.”
The bottom line is said to be 136 horsepower and 105 pound-feet of torque. For the current R1200 GS, the claim is 125 horses and 92 pound-feet. The star of the video is the 2019 BMW R1250GS; the same Shift Cam technology will be present in the 2019 R1250GS Adventure, R1250R, R1250RS, and R1250RT as well.
There’s no spec in how much weight Shift Cam will ad, but it appears to be not much. In the vid, it looks like a small (and light) stepper motor below the intake cam’s shift drum is what slides the cams to and fro. Very clever and non-invasive.
We’ll have more as further information emerges of BMW’s new boxer models. Expect to see at least a couple of these next month at Intermot, and possibly EICMA if BMW decides to split the models up over two shows.
More by John Burns