Electro-motive throttle actuator syncs the throttles on the fly...put your twinmax on ebay and get on the wait list
There was mention of something along the lines of "automated decompressors" during startup. Can anyone point me to that? Going to have to float a valve for that to happen, and I hadn't seen that anywhere.
I found this in the BMW press release. No sure if it answers your question or not. You can read more on page 177 of this thread As before, the two respective camshafts are driven by a chain running in the shaft behind the cylinders (on the right-hand side of the engine from the counterbalance shaft and on the left from the crankshaft). The timing chain drives an intermediate shaft between the intake and exhaust camshaft and it is from here that power is transmitted to the camshafts via spur gear pairs. At each exhaust camshaft there is an centrifugal-force-driven decompression facility which facilitates the start-up process. This makes it possible to save weight in the starter motor and battery.
Seems unusual for one cylinder cam chain to run off the crankshaft and the other running off the counterbalance shaft. Seems some valve timing issues could result in gear wear from the counterbalance shaft and crankshaft relationship....
There's no TB sync maintenance on the S1000RR and it's an inline-four. Perhaps the same technology. - Mark
I think most engine architectures share a common throttle body so there is nothing to sync...the nature of a boxer engine makes sharing a throttle body problematical. Although a beast like the S1000RR probably has individual throttle bodies for each cylinder.
A few of the newer non-single bikes with an emphasis on efficiency do use a single TB (the NC700X comes immediately to mind) but I think it is uncommon. The S1000RR definitely has individual TB's, but I've never seen anything definitive about why they don't require any synchronization. It is definitely drive-by-wire, so each TB is controlled by a servo but I would still think there would need to be some calibration to make sure all the servos and position sensors are properly synchronized. It may be one of those things where BMW feels that once set at the factory, it should never go out of synchronization. I certainly know of many bikes that have servo TB's and still have conventional air bleed screws and require periodic synchronization by balancing manifold vacuum with the bleed screws. Short of having a MP sensor that measures vacuum in each inlet tract, I don't know of any way for the system to adjust itself based on running conditions. - Mark
I read something about the new GS having something that measures vacuum and then makes adjustments constantly.
Very good list, I big factor is a Yamaha S10 is 13K, and I plan on $3500 in mods out of the box so it will be 16.5 and the value will drop pretty fast. 2012 BMW is 17K and the question is can I live with it mostly stock and add about 1K in mods? A 2013 set up the same will be 19.5K estimated and the aftermarket will not have a pile of items so could I might have to live with 1K in Mods. Reviewing used bike selling prices the BMW does not drop as fast as the S10 so in 5 years the diff in total cost may be very small. I was going with a 1200 gs in 2009 and picked up a 2 year old KTM 990 Adventure and it is a great bike, just find it is great off road and good on the road and my needs are great on the road and ok off road.
The current boxers don't require a sync on the idle circuit (idle servo) its only the mechanical cable part that you can adjust part throttle. I don't know if the new drive by wire uses a separate idle, main servo or if it's just one but however they do it now on the idle could be used on the new system.
You can see a centrifugal decompression device on the exhaust cam in the upper right hand corner. Rod
I suspect they wanted the slack side of the chain on the bottom. Look at some of the issues they had with the slack on the top with the oilheads. to do that one side must have reverse drive. Rod
That reminds me of my Tiger 800: I hook up the laptop with diagnostic software and it tells me exactly how the TBs are out of sync, so it knows exactly what's wrong. It's NOT ride by wire though and and it doesn't have a computer controlled mechanism to adjust - so I have to manually adjust them. Would have been so much nicer to get ride by wire and have them automatically adjust via build in mechanism.
New GS retail price in Germany (19% VAT included) has been quoted by a dealer to an inmate in another bmw forum as follows: Base price with ABS 14,100 (plus delivery) Comfort pack 650 Aktiv pack 890 Touring pack 1,490 Dynamic pack 2,100 I'm impressed. They did not go over the top.
Of idle throttle sync. The idle balance can (and should) be checked, but if it is off by more than 25 mbar BMW says check for air leaks and make sure the valves are the same side-to-side. There is no other adjustment specific to idle balance. That's through '09 models... I assume the camheads are the same. It wouldn't surprise me if the LC bikes are the same, less any off idle throttle cable adjustments.