Shift cam or not?
- Thread starter longdog
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My current model 2018 GSA is different to my mates R1250GSA. My 18 is smoother up and down through the GSAP. Its different because of the 50 in the beak sticker. It has a Different plastic plug cover on each cylinder. And of course different paints schemes.
I do notice the power, but The 1200 has more than enough power. If power was so important , id invest in a ducati.
This is my opinion, dont take it as a personal dig at you, or your bike.
Ill wait for the R1300 as the 1250 is basically the same bike as my current 12. (except for the EU emission shiftcam)
I do notice the power, but The 1200 has more than enough power. If power was so important , id invest in a ducati.
This is my opinion, dont take it as a personal dig at you, or your bike.
Ill wait for the R1300 as the 1250 is basically the same bike as my current 12. (except for the EU emission shiftcam)
ThomasGN
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Technically, Ryan is right. But the proof is in the pudding. Try the bike! Always try the bike. In my opinion the new GS is nothing less than marvellous. But that is just me. Others will see it differently. Peace with that.
What is correct? He claims it's old and outdated technology.
But it's not old, it's not outdated. In fact, it's bloody smart in all its simplicity.
He brings up several examples of 'better systems'. He names the Kawasaki system with sentrifugal control. What he fails to mention is that the Kawasaki system favours high rpm engine, and it's used in their 4 cyl engines. However, the Kawasaki system is more complex than shiftcam, it only shift faze, and it reacts to RPM, not engine load.
As a matter of fact, all his examples are faze shift only.
Does it matter? The most advanced faze shift system is to be found in the Multistrada. The system is quite complicated, but does it work? It works as such. But the 1260 Multistrada, offering a fine engine, still deliveres 129NM. The BMW Shiftcam engine, with similar cc offers 143 NM.
The Shiftcam is controlled by two solenoids. What if one fails? No big deal, the engine works just fine, but will offer less torque, as you are reverting to a single lobe system, just like in the 1200LC. Offering 80cc more than the 1200 the 1250 with a none operating Shiftcam will probably still be stronger than the 1200. (depending of the nature of malfunction and which set of lobes are in use)
What if the plunger in the solenoid does not return due to an electrical short, keeping it activated? No problem. The plunger is activated by magnetism. There is no physical lock that blocks it. The tracks at the end of the sliding camshaft are shaped in such a way that if the solenoid is stil out when it shouldn't, the track endpoint will show the lobe back in, and no harm is done. If the lobe should pop out when it shouldn't,(as in wrong faze) likewise, it meets a track that prevents it from doing any movement before the camshaft may slide without causing damage.
The Shiftcam allows for different opening of the valve depending on the engine load and rpm. Sure, a full blown VVT system would work even better. But the VVT is way more complex, and it would cause a wider engine. As such, we may say the Shiftcam is a compromise compared to VVT. VVT would offer even more torque and power, but Shiftcam ads hardly any weight to the engine, nor does it make the engine wider. It is very simple with few extra moving parts, and BMW did not ad to the price of the bike (i.e 2018 1200 and 2019 1250 in same configuration did cost the same, at least in my country).
And Shiftcam has managed to enable BMW to produce an engine with more torque and low end power than any of their competitors.
I've seen several videos of this Ryan fellow. Most of them have been entertaining and informative. But in this video he either haven't understood what he is talking about, or he deliberately acts like a moron to collect clicks.
As a bike is my only personal transport the GS fits the bill admirably, I am concerned that the increasing weight may force me into something less good in the future, which will be sad
Increasing weight has forced me onto a Ktm 790. Excellent bike, but if I had to own only one bike it would be a GS.
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All that just for EU emissions regulations !
Not quite.
BMW does several other engines with no Shiftcam, so if meeting Euro 5 demands was their only goal, they wouldn't have to bother with Shiftcam.
That said, Complying to the Euro 5 regulations is not optional. You either make it or sell your bikes outside the EU.
But in addition to meet the Eoro 5 requirements, they also wanted a more powerful boxer without adding weight and cost, and the combination of a WB O2 sensor and the differential openings for the intake valves the managed to not only make their most powerful boxer to this day, but also the sweetest and smoothest running boxer they have made.
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The boxer was a challenge for ongoing EU regulations. The partial water cooled outlet valves was purely because of EU rules. As is the shiftcam.
BMW doing all they can to keep the opposing twin. And also keeping up with other manufacturers with power output.
BMW doing all they can to keep the opposing twin. And also keeping up with other manufacturers with power output.
And how do you explain the R nine T also meeting the Euro 5 ?
ThomasGN
Registered user
Ryan is technically right. The solenoid cam system is only really optimised at two different levels of revolutions and has introduced electricity in the gearbox. Technological, it could be claimed that BMW has over-complicated a motor to gain a little torque and some HP while complying to emission regulations. Would I buy one anyway? YES!
So what is all the fuzz about? Ryan is not an oracle. He has his opinion - you have yours. But that does not change the fact that Ryan is TECHNICALLY right. His verdict is something else.
However, in the real world the system works. That is why I emphasised to try the bike out. The new GS is marvellous - despite Ryans verdict.
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Bloody good question that. I would think that its restricted with less power output to keep below the limits ? Ill be on this tomorrow.......
ThomasGN
Registered user
If one wants to make a problem out of it, so technically, yes. But then, what about regular camshafts with only one lobe. That is the option. And for a single rpm only?. The switching point is dynamic, based on engine load and rpm. He chose to focus on the fact that it is not perfect, rather than pointing out that even if it is not perfect, it is better than anything else from any of the competition.
And introducing electrics in the engine? Give me strength.... The engine is already full of sensors and different electric components, including the generator. The coils are smack in the middle of the head, producing 20 000V. Two more wires in the head does hardly make a difference. I fail to understand why a wire inside an engine is a problem. Even the Norton Commando had wires inside the engine, and that was a Lucas system.
He deliberately makes a point out of nothing. Perhaps he is able to impress someone that knows nothing about modern engines. But to anyone that has seen one up close, his video appears to be an act of a moron....
You are somewhat tedious in your posts .
I would , but I upgraded to the 1250 as the 1200 was missing something , the 1200 as good as it is was lacking that bite . Your views are fine and correct from your perspective, I own one and have owned several 1200 bikes , the 1250 is better .
Sorry if a bit curt but 18 days doing 12 hrs non stop is taking its toll . I’ll be buying a KTM next lol
I wish , just on way to start another strip down .......
Coffee is the answer , prefer a beer mind but not allowed on pre shift ...
I have an Urban GS... Euro 5 version of the old Twin Cam engine. It goes like stink!
It pulls well everywhere and uses very little fuel. It's been on the Dyno and produced some very healthy looking graphs.
It feels really nice to ride (engine, not the seat). Similar to previous TCs that I've owned (pre Euro 5).
Only difference that I can see is the charcoal canister... Can't see it now though... It went in the bin
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Probably unrelated to the bike being a shift cam 1250, but a riding mate of mine with an R1250GS flashed up a couple of warning lights on his screen just 2 weeks after the first service. He took his bike to the Motorrad dealer where he bought it from just a few weeks ago. The service department diagnosed “a sticking exhaust valve” but they are not sure why it has happened.
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