Detuning my 1200RT

[Rogslater]

Yes, Yes, I can hear the uproar from the "power is everything" types.
I am really keen on softening up the engine on my 1200RT to make it more practical.
I have had to reject my first choice of fitting the 900RTP parts because of expence, to many parts need to be changed.
Best money effective seems to be to change to 1200GS lower compression pistons and slightly milder cams. This knocks off some power at high revs but increases both power and tourque at the revs and road speed I normally use in every day riding. As a example, the 60 to 80mph 6th gear role-on numbers are faster for the GS, this is the practicality I am looking for.
My concearn is a possible disproportional drop in fuel consumption from the excellent numbers acheived by my standard RT.
There seem to be reports of very poor mileage numbers from GS owners. My question, is this lower consumption more due to wind resistance of the two models or is the slighly milder GS engine the main culprit? I can't find specific fuel consumtion numbers from BMW on the two engines.
Any ideas, or better still, experiance would be most welcome.

Roger

[MPMARTY]

Higher compression yields more efficient use of fuel up to the point of detonation. Thus "detuning" your RT will reduce the efficiency. If I were looking for more usable torque at your described 60 to 80 mph speed I'd just leave it in fifth gear. I know not as much fun as redesigning the wheel.

[Donster]

Your bike is capable of going just as slow as a Vespa. It's all in the wrist.

[35634]

I have heard of "throttle stops" that can be set to prevent fully opening the throttle.
I doubt that major engine work would be cost effective, and would lower resale value.

[mclassing]

Roger,

Have you considered the F800ST (http://www.bmwmotorcycles.com/us/en/bikes/tour/f800st/f800st_main.html)?

It doesn't come with bags but is only listed for around $ 10 K.

It even has a belt final drive so you don't have to worry about FD failure. :clap

I love my R1200 ST. The only improvement (besides replacing the stock seat) I think it needs is a little shorter first gear. Loaded down with a passenger, I have a tendancy to stall the bike -- it is too tall for my likes.

[Rogslater]

Roger,

Have you considered the F800ST (http://www.bmwmotorcycles.com/us/en/bikes/tour/f800st/f800st_main.html)?

It doesn't come with bags but is only listed for around $ 10 K.

It even has a belt final drive so you don't have to worry about FD failure. :clap

I love my R1200 ST. The only improvement (besides replacing the stock seat) I think it needs is a little shorter first gear. Loaded down with a passenger, I have a tendancy to stall the bike -- it is too tall for my likes.

Mike
I rode a GS few days ago, it really did have more grunt at normal road speeds (zero to 80) than my RT plus the engine felt softer and more pleasant in traffic and at idle. This increase in torque helps under heavily loaded up hill starts that the RT is not at all good at. No, I would not consider a F series. My boxer RT is a real BMW, I am just trying for a bit less "sport" and more "tour".

[tbryant]

Dude...The F series are real BMWs too. Maybe you should have bought a Harley if you want torque without power.

[rinty]

What do you mean by making it more "practical"? Is the bike too powerful, or do you just want to be able to run lower octane fuel?

Jes' askin' :)

[ojhengen]

Could it be that the reason the GS has more accelleration at 60-80 is because of its lower gearing? The gearing in the RT and GS are not the same, you know. That is one of the reasons the RT has greater range than the GS Adventure, even with less fuel. Look at the specs.

[ojhengen]

Not wanting to let go of this, I have uploaded spec sheet info, so alcon can see why the two bikes differ in mileage and (assumed?) accelleration. Logically, lower gearing would give the bike more oomph at certain speeds, and the GSA is definitely lower-geared. I can upload only one at a time, so here is the GSA sheet.

[ojhengen]

And here is the RT Spec Sheet. Interesting to note that the RT actually will carry a heavier load than the GSA, isn't it? Most GSA owners think that they have the edge, I'd bet. The RT is better for all-around touring use because it can go further, more comfortably, cheaper, quieter and other things I can't think of right now. I do wish that I had a super-low first gear on the RT for really slow driving in gravel and dirt/mud, though.

Personally, I would not even think of detuning the RT. As suggested by another rider, just switch to 5th gear!

[j-budimlya]

You can do a mild detune by opening up the gap on the valve adjustment....

This will delay the valve opening a bit and reduce the peak valve opening

I'm not sure how much power it will reduce and how far you can go with this approach, but it should trim peak power and delay power onset a bit.

Seems crazy to me, but its your bike.....

[mclassing]

Mike
I rode a GS few days ago, it really did have more grunt at normal road speeds (zero to 80) than my RT plus the engine felt softer and more pleasant in traffic and at idle. This increase in torque helps under heavily loaded up hill starts that the RT is not at all good at. No, I would not consider a F series. My boxer RT is a real BMW, I am just trying for a bit less "sport" and more "tour".

I understand what Roger means by "real BMW." It has the BMW heritage with the drive shaft and boxer setup. I believe that in addition to final drive gearing that the GS models also have different cams and possibly compression. If you can define these pieces parts you could swap them out? You also then get into CANBUS programming. I think it would be quite a job.

[mreimler]

I am really keen on softening up the engine on my 1200RT to make it more practical.

My mind is boggled.

[marchyman]

The RT is better for all-around touring use because it can go further, more comfortably, cheaper, quieter and other things I can't think of right now.

Depends a whole bunch on the rider. I prefer the GS (regular, not adventure) to the RT because it is lighter. That in itself makes it a whole bunch more comfortable for me. Take 150 pounds off of an RT and increase the suspension travel to 7 or 8 inches and yes, I'd probably like it better than my GS.... until it came time to service the beastie leaving me looking for a place to hang the plastic without tripping over it in the garage. :stick

Even on the GS 5th is sometimes a whole bunch more fun than 6th.

[Andy VH]

One of the much easier ways to "detune" an engine is to restrict the incoming air to the engine. Generally speaking, longer, smaller diameter intake tubes into the throttle bodies will generate higher velocity airflow at lower engine speeds which produces a stronger lower end torque curve.

When the RS Oilhead first came out, one easy mod was to install the TB intake tubes from the GS. The GS tubes were much longer and stuck into the airbox much further back. The result was stronger mid-range, at the expense of some top end rpm power. But it also created more intake noise or "honk". I know this is true because I did it on my 94 R1100RS.

Longer intake tubes and a rear drive ratio from a GS may get you what you want.

[Rogslater]

Dude...The F series are real BMWs too. Maybe you should have bought a Harley if you want torque without power.

You are correct, my apology for poor choice of words. The long version of what I meant was, for me personally, the quintessential BMW is a German made, shaft drive flat twin. I still have three of them.

Roger

[JKERSH1]

France has a 100 HP limit on motorcycles. In the old days this was accomplished with carb plates or restrictions, but if I understand it correctly with today's engines it's accomplished via changes in the Motronic electronic engine management. Maybe your dealer could change the Motronic mapping?

[hlothery]

I remain really confused about what you want from your RT. Less power, but more torque confuses me. If the "uphill, loaded starts" is your main worry (and it was mine before I sold my RT) that is all in the tall first gear. Perhaps you could just change gearing, if you must redesign the bike. It would take a lot of torque to overcome that ratio, IMHO. As far as how the engine behaved in traffic.....again, are we just talking about the starts from stop and go traffic? I found nothing wrong with the RT after I got it going.

[Rogslater]

Yes, Yes, I can hear the uproar from the "power is everything" types.
I am really keen on softening up the engine on my 1200RT to make it more practical.
I have had to reject my first choice of fitting the 900RTP parts because of expence, to many parts need to be changed.
Best money effective seems to be to change to 1200GS lower compression pistons and slightly milder cams. This knocks off some power at high revs but increases both power and tourque at the revs and road speed I normally use in every day riding. As a example, the 60 to 80mph 6th gear role-on numbers are faster for the GS, this is the practicality I am looking for.
My concearn is a possible disproportional drop in fuel consumption from the excellent numbers acheived by my standard RT.
There seem to be reports of very poor mileage numbers from GS owners. My question, is this lower consumption more due to wind resistance of the two models or is the slighly milder GS engine the main culprit? I can't find specific fuel consumtion numbers from BMW on the two engines.
Any ideas, or better still, experiance would be most welcome.

Roger

I really should have known better than to have the temerity to enquire if any one had any experiance of a little softening of my 1200RT engine.
Thank you the few kind souls who did provide constructive sugestions, I appreciate it.
For the rest, I find the derisively childish comments to be un called for.
For the record, I am a vertically challenged geriatric with opprox half a million miles and fifty five years of two wheel experiance. This was mainly in Europe on bikes from Ariel, Guzzi, Norton, Laverda, Velocette, Vincent and yes, BMW's from the sixties to modern. I still have a R90S, R80RT and R1200RT. This summer I have covered 12,600 miles on the 1200, 3,200 on the RT80 and 2,400 on a 1976 Guzzi thousand.
After some fairly intensive investigation I have decided to leave my 1200 engine alone. As I feared, the slightly milder tune of the 1200GS does, according to BMW, suffer a disproportinate 15% increase in fuel consumption. I will continue to use it for what it is so supurb at, long distance interstate burning. For 55 mph restricted trips I will use my oh so sweet 80RT and for local shopping in traffic I will use the Guzzi.

[rinty]

No offense intended, Rog. I was just interested in what prompted your proposed project. :)

I agree that the 1200's have more than adequate power.

[TomfromMD]

.
For the record, I am a vertically challenged geriatric with opprox half a million miles and fifty five years of two wheel experiance. ... For 55 mph restricted trips I will use my oh so sweet 80RT and for local shopping in traffic I will use the Guzzi.

Although I've only been riding for 35+ years, I'd urge you to give the RT another chance for general use.

What works for me is realizing that the combination of a light flywheel (compared to the airhead) and a super tall 1st gear makes the initial launch a bit harder. I find that gently engaging the clutch at around 1,500~2,000 rpm helps smooth things out - increasing that by about 500 revs when 2 up or headed uphill. I also find that I downshift to 1st for very slow corners which my old /6 would handle in 2nd with ease.

Hoping you continue to enjoy all your bikes.

Tom

[Ludell]

Less power, but more torque confuses me.

Remember that HP = Torque x RPM. It is entirely possible for one engine to deliver more torque at lower RPM's but have the torque drop off at higher RPM's thereby limiting max HP. OTOH, another engine that starts with lower torque at low RPM's but continues to hold its torque all the way up to high RPM's can make more HP.

I personally prefer torque to peak at the RPM's the engine will be used at most often even if it means giving up max HP, so I can see where the OP is coming from.

[TomfromMD]

I personally prefer torque to peak at the RPM's the engine will be used at most often even if it means giving up max HP, so I can see where the OP is coming from.

According to BMW, the GS peaks at 85 ft lbs @ 5750 rpm and the RT's 85 ft lbs peak is reached at 6,000. The difference equates to about 4 mph in top gear (107 vs. 111)

Tom

[Ludell]

Agreed, not much difference between the GS and RT - we would have to see the actual torque curves to know if the GS is any fatter at low RPM's. If the GS is geared lower that would certainly make it feel torquier.

[dstuckmann]

Hi,
I have not used this but you may find that it is what you are looking for...

http://www.powerfrkusa.net/cgi-bin/shopper.cgi?preadd=action&key=1024BR12001LBPRS

http://forums.pelicanparts.com/bmw-r1100s-r1200s-tech-forum/503413-lennies-cam-sprocket-review.html

Dean
'08 R1200RT
Newton, WI

[Bob1100RTC]

For the price, I may pick up a set for my RT next year when it goes out of warranty. I have played with cam timing on a lot of hi-perf engines I have built over the years and it does make a difference. I read somewhere that there is a 2.90 gears set for the RT. That is what I would really like, a little more power pulling out.

[JK]

Yes, Yes, I can hear the uproar from the "power is everything" types.
I am really keen on softening up the engine on my 1200RT to make it more practical.
I have had to reject my first choice of fitting the 900RTP parts because of expence, to many parts need to be changed.
Best money effective seems to be to change to 1200GS lower compression pistons and slightly milder cams. This knocks off some power at high revs but increases both power and tourque at the revs and road speed I normally use in every day riding. As a example, the 60 to 80mph 6th gear role-on numbers are faster for the GS, this is the practicality I am looking for.
My concearn is a possible disproportional drop in fuel consumption from the excellent numbers acheived by my standard RT.
There seem to be reports of very poor mileage numbers from GS owners. My question, is this lower consumption more due to wind resistance of the two models or is the slighly milder GS engine the main culprit? I can't find specific fuel consumtion numbers from BMW on the two engines.
Any ideas, or better still, experiance would be most welcome.

Roger

Hey Roger -

Simple solution is more beers and brats for you and your copilot. By beefing up your collective lovehandles and fortifying the buns and jellyroll, the jugs and shaft of your RT wll assume a more harmonic ocean of forward motion that will tide you over in the ups and downs of life's joyous journey. Furthermore, more shade in summer and warmth in winter will also be appreciated.

In short, bottoms up always works for me.

J.K. :wow

P.S. Dropping a blue pill in the tank will also stiffen the suspension and take out any slack in the drivetrain.

[mogu83]

And this is why I ride a R1200R

[maxscycle]

Granted I have a r12gs, not an rt. But maybe if you tried to do your normal shifting at 3,700 to 3,800 rpm. You may achieve your goals. My gs never sees 4,000 rpm unless I'm in high gear.
It has more than enough power for me and what I need it to do. I never take it off road. But I also get about 19,400 miles out of a rear tire before I need to change it. My front last about 21,000 miles before it gets changed. I'm happy with it. :clap
max

[1analguy]

...Take 150 pounds off of an RT and increase the suspension travel to 7 or 8 inches and yes, I'd probably like it better than my GS...

150 lbs...really? That would put your GS at about the same weight as a new 1000RR. I'm not buying it. How much do you think an RT weighs, anyway?

I know exactly what the OP means. I'd gladly sacrifice a bit of peak horsepower if I could have some off-idle torque in exchange. The RT's engine was designed to sparkle on the autobahn and I'm sure it does, but I don't live there so either a wide-ratio transmission (with a shorter 1st and a taller 6th) or more low-end grunt would improve the ride-ability for me. My bike rarely sees more than 4000 rpm. As a result, my fuel economy is usually quite good, but I suspect the 12:1 compression also has something to do with this. I talked about this with my dealer and he suggested a '10 RT. I told him that I had seen a '10 cutaway cylinder head. The new valve train geometry was pretty scary-looking, from a potential long-term wear perspective. Call me nuts, but I think a diesel version of this bike would be kind of interesting...;)

[marchyman]

150 lbs...really? That would put your GS at about the same weight as a new 1000RR. I'm not buying it. How much do you think an RT weighs, anyway?


Uhhh, I wrote about removing weight from an RT, not a GS. Removing 150 from an RT would make it a little lighter than a GS. When I went from a '02 R1150RT to an '05 GS (yeah, I know, oilhead to hexhead which is not a direct comparison) I dropped about 150 pounds in weight and gained some in suspension travel.

My point was that I like less weight and more suspension travel which are some of the reasons I ride a GS.

[SPOKESMAN]

As I recall, if you take 150# off of an RT, it would be about 110# lighter than a GS. I wouldn't call that "a little."

However, the BMW Motorad Site is down, so I can't quote exact figures. If my recollection is off, I'll cheerfully eat crow.

[TomfromMD]

As I recall, if you take 150# off of an RT, it would be about 110# lighter than a GS. I wouldn't call that "a little."

However, the BMW Motorad Site is down, so I can't quote exact figures. If my recollection is off, I'll cheerfully eat crow.

Site is back up - BMW quotes 570 lbs. for the RT and 504 lbs. for the GS, so removing 150 from the RT would make it 84 lbs. lighter than the GS.

It may be useful to remember that back in '05 when it ws introduced, at least 2 cycle mags wighed the 1200 RT at around 630. Subtracting 15 lbs. per saddlebag still indicates that BMW was hedging by 30 lbs. or so. Maybe their scales are calibrated by the same folks who do the speedometers!

Tom

[SPOKESMAN]

Yeah, I forgot that the model year changed over half way through the lifespan of this thread. I was quoting my recollection of the BMW-published '09 GS vs. '09 RT figures, which I believe went 473# vs. 505#, dry.

The '10 RT no doubt gained some weight with the added valve train complexity.

Anyway, my point is, regardless of whether we are talking '09 or '10, the weight advantage of the GS is nothing close to the near-150# suggested above.

And this analysis assumes that the BMW-published figures are close to accurate. I've never actually weighed either model. If the BMW-published delta is way off the mark, then you can throw this post out the window.

[marchyman]

Anyway, my point is, regardless of whether we are talking '09 or '10, the weight advantage of the GS is nothing close to the near-150# suggested above.

I prefer the GS for MANY reasons, one of them because it is a lighter bike. But given an RT and a GS of exactly the same weight I'd still pick the GS. An RT would have to be drastically lighter than the GS to get my attention. Thus my comment... I'd only consider an RT if it were 150 pounds lighter.

I went from a close to 620 lbs R1150RT to close to 500 lbs R1200 GS. Alas, I've since added enough junk to the GS to get back at least half of the weight I lost by making the switch.

Apparently I'm having a hard time explaining myself. So it goes.

[welafever]

i would ride a diesel bike....

[Anyname]

Mike
I rode a GS few days ago, it really did have more grunt at normal road speeds (zero to 80) than my RT plus the engine felt softer and more pleasant in traffic and at idle. This increase in torque helps under heavily loaded up hill starts that the RT is not at all good at. No, I would not consider a F series. My boxer RT is a real BMW, I am just trying for a bit less "sport" and more "tour".

For a fairly noticeable sum of money, Max BMW will sell you a final drive unit with a lower ratio. It sounds like just what you want:

http://www.maxbmwmotorsport.com/r1200-30-final-drive-upgrade/

[ka5ysy]

And this is why I ride a R1200R

+1.

Think of the R1200R as an RT "Lite". Same luggage, lighter weight, less filling. And it can embarrass most crotch rocket drivers in the twisties :dance



:lurk

[pch123]

For a fairly noticeable sum of money, Max BMW will sell you a final drive unit with a lower ratio. It sounds like just what you want:

http://www.maxbmwmotorsport.com/r1200-30-final-drive-upgrade/

This is exactly what the OP wants. Don't stuff around with the motor. That will kill something else. Change the gearing, either first gear ( to fix your take off issue) or the final drive ratios to fix overall pull power. Easy. Admittedly not many would want to or would do so, but.. If that rows your boat mate...
regards
paul

[Bezdelnik]

Only having my RT since October I may not be as experienced with the bike, but I am loving it. After coming off a crotch rocket the RT is greatly appreciated. The taller gears and low end torque are greatly appreciated. Instead of having to shift as often and not experiencing the second burst of power in the high RPMs I appreciate the power and torque of the RT. Much more linear. The RT is a big bike and you have to take that into account. If the power is to much maybe you should look at a smaller more flickable bike. I am trying to get used to a big bike and look forward to taking the MSF advanced class to help me get a better handle on the low speed handling and overall control.

[1analguy]

This is exactly what the OP wants. Don't stuff around with the motor. That will kill something else. Change the gearing, either first gear ( to fix your take off issue) or the final drive ratios to fix overall pull power. Easy. Admittedly not many would want to or would do so, but.. If that rows your boat mate...
regards
paul

You're right...the whole story with the RT is the gearing. The ratio spread in the transmission is a bit narrow for our use. Having the upper gears so close in ratio makes for great high-speed performance (autobahn), but if all the gears were spread as widely as 1st, 2nd, and even 3rd, it would have resulted in 6th being tall enough that, when combined with a shorter RTP-style final drive, the resulting top gear would be similar to the top gear we have now and 1st gear could then have then ended up being low enough for easy take-offs. Win/Win...