Question about R1200S at 4-5k rpm

[Cloud9blue]

Hey all,

Had this new-to-me R1200S for about a month now, enjoyed every mile on it so far. However, the engine response when under hard acceleration from revving from 4-5k rpm seems rather unsettling to me.

From what I read on the forum, there is a flat stop around 4.5k rpm. But it almost feels like there is traction control bogging the bike down when giving it a handful of throttle through those rpm. So you can see how severe it is. But other wise the bike pulls smoothly through the rest of the rpm range.

Not sure if this is just how the engine is or this might be a problem that should be looked into.

The bike only has 2800 miles when I bought it and it is now sitting at 3500, so it is barely broken in. FYI, it did have the fuel pump replaced back in 2010, probably because the previous owner did not store the bike properly (guessing it from the low mileage).

[signit98]

This would be the first R12S with traction control.

I sorted mine (very well, I might add) by doing three things:
I installed and tuned a Techlusion fuel management tool and I opened the exhaust and intake to let her breathe the way she needs to breathe.
That took care of the flat spot... POOF, it was gone. Bike was crisp, powerful and willing to rev anywhere...
Enjoy!

[BXR12NT]

I concur with Ralf, a filter,open exhaust and Techlusion no flat spots and nice linear power.

[OwenM]

Mt R12S had a full Remus system with open muffler (no DB killers), there was a noticeable sag in the torque curve around 4500 and it went like crazy above that.
Simply replacing the paper air filter with a Unifilter foam filter pretty much eliminated the problem.

Just the other day I had a R12GS with a similar flat spot around 5500, fitting a Unifilter fixed that as well.

YMMV, but its not an expensive experiment.

[jaytee]

All hexheads have this flat spot to some degree or another. In my experience, the R12S has a more pronounced flat spot than most. This is a bike that is tuned for power from 5k-redline.

Like others, I chased this problem but never completely eliminated it. Read my experiences tuning with open pipes, FRK (air temp spoofer) and Power Commander 3.

http://forums.pelicanparts.com/bmw-r1100s-r1200s-tech-forum/613717-r1200s-dyno-tune-results-full-remus-pc3-frk.html

The AFR shows a rich spot in the stock map through the flat spot. Some of our German friends believe this is a problem originating in the air box and not fully treatable without addressing that part of the bike.

Regardless, while I'm sure Ralf and Co. found some improvement with fueling, every dyno map I have seen on this engine (regardless of fueling or pipes) has this flat spot. Even the mid-range tuned R and RT bikes. It's just exaggerated on our R12S hot rods.

IMHO, YMMW, FWIW, and all that.

[leafman60]

Mine pulls linear and strong with a notable punch up top. Akrapovic full, Uni filter and Power Commander with downloaded map.

[X-Triple]

Originally Posted by Cloud9blue

Hey all,

Had this new-to-me R1200S for about a month now, enjoyed every mile on it so far. However, the engine response when under hard acceleration from revving from 4-5k rpm seems rather unsettling to me.

From what I read on the forum, there is a flat stop around 4.5k rpm. But it almost feels like there is traction control bogging the bike down when giving it a handful of throttle through those rpm. So you can see how severe it is. But other wise the bike pulls smoothly through the rest of the rpm range.

Not sure if this is just how the engine is or this might be a problem that should be looked into.

The bike only has 2800 miles when I bought it and it is now sitting at 3500, so it is barely broken in. FYI, it did have the fuel pump replaced back in 2010, probably because the previous owner did not store the bike properly (guessing it from the low mileage).

I had this problem with my old R1100S prep and with a BCR. I had bought the chip for the prep and the FRK for the BCR. Both worked well but favor the FRK overall for ease of install and results.

I was lucky enough to find a fully Farkled R1200S and install the FRK 2 as well getting rid of the canister. I should have had ridden the bike before I bought the FRK but couldn't pass up purchasing it on a good deal. So I don't know what i am missing but I have not witness this flat spot, it does start up easier and idle better.

[shreddr]

an ECU rewrite will remove the flat spot.

[Cloud9blue]

Thanks for info everyone. Guess I just have to deal with for the mean time.

[johnvalls]

Originally Posted by signit98

This would be the first R12S with traction control.

I sorted mine (very well, I might add) by doing three things:
I installed and tuned a Techlusion fuel management tool and I opened the exhaust and intake to let her breathe the way she needs to breathe.
That took care of the flat spot... POOF, it was gone. Bike was crisp, powerful and willing to rev anywhere...
Enjoy!

... 30,000 miles later, the bike is still rides like a dream come true!!

[signit98]

Glad you still have AND are enjoying her, John!

[lkchris]

Check your spark plugs, especially the "main" (horizontal) plugs.

On my 2008 RT both had cracked insulators, I believe due to improper factory assembly. (They hammered on the stick coils)

Certainly killed poor acceleration at rpms mentioned as well as poor hot idle when I replaced them.

[Bob Hancock]

Lennie's sprockets will help the mid-range too. After you've done stuff mentioned above.
My bike had stock cans, Remus headers, FRK, Aussie foam filters and Lennie's cam sprockets and it was stout everywhere.

[shreddr]

The R12S does not need Lennies sprockets, I don't think any of the boxers do, they are 1200cc twins ferchristsakes. There is probably no single engine configuration that has more midrange to begin with. But if you put them in and think they help thats all that matters.

I do know that my BCR was so over weight and underpowered that it took a rise in the road a handful of throttle and a tug on the bars to get the front wheel off the ground. The "sprockets" negated a need for the rise in the road at the cost of a perceptible loss of top end power. The R12S is a powerful motor in stock config and can be turned into a rocket with a proper ECU rewrite and exhaust. The HP2S is better still and a blip of the throttle gets the front wheel aloft in most gears.

I have no personal mission against Lennie, but if the sprockets were the hot set-up he would be selling them as fast as China could make em.

[tjs]

With such a low mileage bike, I wonder if it ever had the BMS-K reprogramed with CIP 7.0.
This info came out of a SIB dated 08/06.
R1200S- ridability modification: Improved, more responsive throttle response. Stops the engine "choking" when the throttle valve is opened abruptly. Generally improved ridability.

Made a big difference on mine. 2cnts from tjs

[Cloud9blue]

Originally Posted by tjs

With such a low mileage bike, I wonder if it ever had the BMS-K reprogramed with CIP 7.0.
This info came out of a SIB dated 08/06.
R1200S- ridability modification: Improved, more responsive throttle response. Stops the engine "choking" when the throttle valve is opened abruptly. Generally improved ridability.

Made a big difference on mine. 2cnts from tjs

Humm, I gonna have to look at the paper works on previous service done on the bike. But a good call.

[Cloud9blue]

Spent a whole day on the bike again, and getting more and more use to this engine. Lets be honest, there is no sane reason to use more than 50% of its power on the street. A gentle roll-on of the throttle solves the problem pretty well for me, for now.

Nonetheless, might get a filter and boosterplug or equivalent once I get more miles on the thing.

[OwenM]

Originally Posted by shreddr

The R12S does not need Lennies sprockets, I don't think any of the boxers do, they are 1200cc twins ferchristsakes. There is probably no single engine configuration that has more midrange to begin with. But if you put them in and think they help thats all that matters.

I don’t "think" they work, I know they work, that's why I have them fitted to both of my BMW R1200 bikes. The improvement in low end smoothness and torque is invaluable to me and I expect most others as well.
Having said that, I dont see Lennies sprockets as a cure for the R12S 4.5K rpm flat spot and quirky-unpredictable throttle response. A Unifilter would be my first priority to address the flat spot followed by a temperature spoofer.

Originally Posted by shreddr

I do know that my BCR was so over weight and underpowered that it took a rise in the road a handful of throttle and a tug on the bars to get the front wheel off the ground. The "sprockets" negated a need for the rise in the road at the cost of a perceptible loss of top end power. The R12S is a powerful motor in stock config and can be turned into a rocket with a proper ECU rewrite and exhaust. The HP2S is better still and a blip of the throttle gets the front wheel aloft in most gears.

It seemed to me that BMW where well aware that the R12S was very prone to wheelies and used ignition timing to control that tendency. Crack the throttle too quietly and ignition advance is limitedly to control front wheel lift, nice and safe but not much fun.
Even with its long wheel base the R12S makes more than enough power to loft the front wheel, BMW deliberately intervened to limit such anti social behaviour and “make it safe”.
An ECU rewrite is probably the only way to get around that limitation.

Originally Posted by shreddr

I have no personal mission against Lennie, but if the sprockets were the hot set-up he would be selling them as fast as China could make em.

Lennies sprockets with a Unifilter and temperature spoofer are without doubt the “hot” set-up for a flat twin BMW, but unfortunately few people are aware of Lennies sprockets and what they do. Even fewer are prepared to go to the effort of fitting them, so little wonder they are not hot sellers.
Those who have lived with such a setup are unlikely to want anything less, I sure don’t.

[Paulaner]

I rode a friends 1100s with the sprockets, otherwise it was same bike as mine.
I did like the punch right off idle, but for me and my style of riding, I prefer the stock cam setup.
When I'm in the mountain twisties (thats pretty much everywhere in my area), I like to keep the engine singing about 4-5k rpms, ready to jump up to the limit, and also with plenty of engine braking available. With the sprockets, the bike felt out of breath up top......

Yes, I get crap mileage when I'm out having fun (keeping revs up), but 35mpg is still almost twice what my Bimmer 545 gets (having fun).

Sprockets are good, they do just as advertised. Just not what I am looking for!

[OwenM]

It seems the people who noticed a loss of top end with sprockets installed are R1100 owners.

My R12RT and R12GS both make more power than stock over about 80% of the rev range with sprockets installed, about the same as stock for 10%, and maybe a little less than stock for about 10% above 7000rpm. I say maybe because I cant actually notice any loss.
The flattening of the power curve may make it seem like the top end is deficient even if its not.

The R12S has more aggressive cams and is tuned for more top end power. Installing Lennies sprockets on the R12S is more likely to incur a noticeable loss in top end but also potentially provide greater gains down low where the S is not strong.

It all comes down to what people are after. If maximum performance above 7000rpm is of greater importance then the 1500 to 7000rpm range installing the sprockets is obviously not advisable.

I would suggest that if power above 7000rpm is what floats peoples boat, an air cooled flat twin BMW is not the ideal tool.