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Where's the power?


cabbage

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More riding today on my recently bought 1100RT.

 

I've nothing to compare it with as I've not ridden any other beemers. It will arrive at 100mph without too much fuss and sits there as solid as a rock. The steering is superb. The brakes are good.

 

It's the accelleration that seems lacking. The best I could say is that the accelleration is modest. Overtaking at speeds above 70mph need to be carefully planned as the bike just won't simply blast past as a similar sized Japanese four might. It seems to need a bloody good thrashing to make it perform even a little.

 

What power there is seems to arrive at over 3500 revs....is this normal?

 

Am I expecting too much or is this modest performance the norm?

 

Cabbage

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To get any kng of respectable roll-on you need to be closer to 4500 rpm. Despite being a big twin they like revs.

 

Bimble along at low revs and you wiull get good MPG but may carbon up the engine, although this is less likely our side of the pond due to different fuel makeup.

 

Cya, Andy

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ShovelStrokeEd

It is more or less the norm.

 

First, the bike is heavy. I don't recall the exact number but a fully gassed RT with even empty panniers will weigh over 600 lbs. More about that later.

 

Second, the motor's HP output is modest at best. Rear wheel HP for an 1100 is on the order of 75 to 80 HP. It also doesn't make a whole bunch of torque below about 5000 RPM which doesn't help top gear acceleration very much.

 

It is also geared a bit tall, compounding all those problems.

 

The simple solution is to downshift when you need to pass in a hurry. The motor doesn't much mind revs so you can take it to near redline on the tach in any gear. Power in the upper reaches of the RPM band is "adequate to the task".

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You've got to rev it, all the way to the redline for max power, it doesn't care, in fact it seems to prefer it.

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With the exception of my old beemer (1962) The rt is my first modern bmw.

 

Everything you said is pretty standard. Look at it this way it's a twin cylinder,

it's opposed and it's restricted both electronically and flow wise.

 

Comparing it to a Japanese in line 4 is just not going to happen. Two different animals.

 

I do find that the bmw is very good at what it does as most here will say the same. I find it the perfect balance between luxury and sport doing both very well clap.gif

 

I rode mine on some seriously challenging roads here in Northern CA last month and it felt really good and for it size can do some wonderful things

very tightly and precisely thumbsup.gif

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It all happens around 4k and over....from memory, on the 1100 motor max torque is around 4700 rpm and max HP is around 7k. I buzz around on my 1150 in the 4/4.5k range....and up grin.gifgrin.gif Only time I am less than 4k is if I am cruising on 55mph Interstates..... grin.gif

 

Don't know your 1100 motor as well as some of the folks around here but if you feel like you need to blow by other vehicles, perhaps you should be dropping down an extra gear at 70 and winding it up to the rev limiter??

 

The gearing on the RT is much more "long legged" than most bikes and, IMHO, it really is what it is...an autobahn cruiser not an out and out stoplight dragster or canyon carver.

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What power there is seems to arrive at over 3500 revs....is this normal?

As others have already indicated, normal indeed. Its not that the motor is anemic, the power band is just a bit higher up in the rpm range...4K minimum up to about 7K ...it works much better there.

 

Overtaking at speeds above 70mph need to be carefully planned as the bike just won't simply blast past as a similar sized Japanese four might.
True...but they don't have that unique boxer character grin.gifcrazy.gifgrin.gif
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The only problem -- with mine at least -- is it begins to get a little buzzy once I head north of 4K rpm. Cruising along at an indicated 80 mph I'm just a bit shy of 4K in 6th, and the engin is smooth smooth smooth. Once I get it up to 4.5K and beyond it gets quite a bit buzzier. I wouldn't want to cruise for miles at those rpm's.

 

I haven't adjusted the valves or TB's yet. I'll probably play with those in a couple of weeks. Perhaps it will make a difference? Or, do they all buzz above 4K?

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The only problem -- with mine at least -- is it begins to get a little buzzy once I head north of 4K rpm. Cruising along at an indicated 80 mph I'm just a bit shy of 4K in 6th, and the engin is smooth smooth smooth. Once I get it up to 4.5K and beyond it gets quite a bit buzzier. I wouldn't want to cruise for miles at those rpm's.

 

I haven't adjusted the valves or TB's yet. I'll probably play with those in a couple of weeks. Perhaps it will make a difference? Or, do they all buzz above 4K?

 

The better the valve adjust and especially the TBS the smoother they are. There will still be vibration, best dealt with by a loose grip on the bars. I just rest my hands on the grips, pinching the throttle with my thumb. No issue with vibes that way.

 

Andy

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ShovelStrokeEd

Don't worry about it, it smooths out again, given a good state of tune, at about 5K RPM. 90 indicated on your bike is probably only about 82 actual so you can more or less feel free to run that fast.

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OK guys, that's fine. It's all part of my learning about the new ride and what to expect from it.

 

Cabbage

 

Hey Cabbage,

Check out www.ibmwr.org

especially the tech articles on the R 1100 RT.

I did the "Intake Tube" and "CAT plug" Mod.

seems to have a lot smoother "power band" at a cost of 5 mph on the "top" end.

The rev limiter cuts in a little sooner so I'm limited to 120 mph top end if my speedo is right.I can live with that. thumbsup.gif

As mentioned earlier don't be too shy to "drop" a gear or two and "spank that sucker" when passing, it should "turn on" nicely for you. clap.gif

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