Acceleration

General discussion of the BMW R1200RT/R1250RT
MEM62
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Acceleration

Post by MEM62 »

The other half and I have just returned from a tour of Spain.  The 2012 RT performed well as it always does.

I only had one issue with it when trying to overtake a van on our way up to Burgos.  I dropped it into 5th gear and started my overtake but once the engine speed reached just over 4,000 rpm the motor just didn't seem to want to rev any further.  The engine felt rough and as if it was running out of steam.  Opening the throttle just increased the roughness without much of an increase in forward motion.  At the time it was running on 95ron fuel as I could not find any 98 and I hope that this was the reason.  I plan to have a run out this weekend having filled the tank with 98 octane in the hope of seeing an improvement. 

Has anyone else experienced anything similar?         
beemerboy9
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Re: Acceleration

Post by beemerboy9 »

It sounds like a spark plug coil pack is giving out.
John Bentall
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Paggers
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Re: Acceleration

Post by Paggers »

I used to own a GS with the same engine and I can say I never experienced anything like that despite constantly running it on 95 octane. I can't offer much in terms of diagnosis advice, but what you described doesn't sound right. Good luck with finding the culprit and getting it sorted.
2016 (2017 MY) R1200 RT LE in white and black. Find me on twitter: @2WheelSolo. Also posting motorcycle vlogs on youtube: https://goo.gl/iM7y6X
mcwhirtj
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Re: Acceleration

Post by mcwhirtj »

My '05 RT has a sort of sluggish/rough spot around 4500 rpm, but once it gets above 5000 it comes "alive", and above 6000 it simply jumps, engine smooths out and it runs like "this is where it's at!" Right up to red line.  Which is just where I'm starting to have fun!  But there is a rough spot in there above 4000, and I've always wondered if it valve lash related or?  But your description sounds like it didn't want to pull through the rough spot and come alive at higher RPM (?).


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MEM62
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Re: Acceleration

Post by MEM62 »

mcwhirtj wrote: My '05 RT has a sort of sluggish/rough spot around 4500 rpm, but once it gets above 5000 it comes "alive", and above 6000 it simply jumps, engine smooths out and it runs like "this is where it's at!" Right up to red line.  Which is just where I'm starting to have fun!  But there is a rough spot in there above 4000, and I've always wondered if it valve lash related or?  But your description sounds like it didn't want to pull through the rough spot and come alive at higher RPM (?).


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I could have dropped it another gear and gunned it but I have some mechanical sympathy for my bike.  I really hope it was just crappy fuel.  I'll report back over the weekend. 

mcwhirtj
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Re: Acceleration

Post by mcwhirtj »

MEM62 wrote:
I could have dropped it another gear and gunned it but I have some mechanical sympathy for my bike.  I really hope it was just crappy fuel.  I'll report back over the weekend.
From what I have read and experienced, the bike is made to run up to red line!  All the fun is in the last 2k rpm  ;)
guest2360

Re: Acceleration

Post by guest2360 »

You've read wrong.  Anybody out there agree with me.
LAF
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Re: Acceleration

Post by LAF »

He is dead wrong.

After multiple dyno runs and a tune, the motor is done at 7600-7800 RPM, period!

As far as abuse as long as you were under 100 MPH 4th gear would have been fine.  Seriously the bike would have had no issues going into 4th for you.
Last edited by LAF on Sun Jul 16, 2017 1:41 am, edited 1 time in total.
guest2360

Re: Acceleration

Post by guest2360 »

Whose dead wrong.  Most  dyno charts show you have near maximum torque from about  4000 to 6000 rpm so that's the place to be.
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exportman
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Re: Acceleration

Post by exportman »

The OP  does not say what the gradient was like or how much the bike was loaded.  Personally with two up  I would have been in 4th even on a down hill  just in case I needed that instant poke.    Running the engine to the red when it warm is not going to do any harm with a well looked after bike.  Trying to pull max power from low revs  just may.
guest2360

Re: Acceleration

Post by guest2360 »

Would suggest if your running an RT to the red line on a regular basis it's not a well looked after bike, it's a thrashed one.  The other way round from about 4000 rpm, ideal. I remember an owner complaining bitterly to our workshops that his bike hesitated at every gear change first to sixth.  You can guess what he was doing.
Last edited by guest2360 on Sun Jul 16, 2017 9:29 am, edited 1 time in total.
LAF
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Re: Acceleration

Post by LAF »

RTman10 wrote: Whose dead wrong.  Most  dyno charts show you have near maximum torque from about  4000 to 6000 rpm so that's the place to be.
The poster who says the best place to be is the last 2000 RPM to red line.  There is NOTHING there from the motor it is done making any power at 7600-7800 RPM.

I had my bike on a dyno for at least 12-15 pulls over two sessions.  The tuner was impressed 113 HP and 83 TQ, but as I say the bike is done at 7600 RPM.

The bike likes 5000 to 7000 RPM for running hard.  It does like and shift better in the higher RPM and is made to be run at higher RPM.  Dyno proved it, seat of the pants and my heart proves it every time I ride it.  I have gotten a bit excited from too much twist of the grip and when the front end get really light my heart starts thumping really hard.

And the original OP it almost seems to me he was experiencing pinging or bad gas or both.  And as I say if he would have went to 4th it would have been no issue loaded and 2 up.  You are not going to hurt these bikes in the 5-7500 RPM range at all they love it and are built to be there.  And sure up to 9000 wont hurt it but no need to go there just drop a gear and hold the hell on.

MEM62
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Re: Acceleration

Post by MEM62 »

exportman wrote: The OP does not say what the gradient was like or how much the bike was loaded. Personally with two up I would have been in 4th even on a down hill just in case I needed that instant poke. Running the engine to the red when it warm is not going to do any harm with a well looked after bike. Trying to pull max power from low revs just may.

Two up.  Rider 14st, passenger 10st + luggage.  Slight uphill gradient.  Bike only usually needs 4 - 5,000 rpm to overtake in these circumstances and will pull from 3,000 through to 5,000 easily.  Pleased to say that we had a run out today and normal service has been resumed.  Guess it may have been down to some poor quality fuel as suspected.     
LAF
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Re: Acceleration

Post by LAF »

MEM62 wrote:
Two up.  Rider 14st, passenger 10st + luggage.  Slight uphill gradient.  Bike only usually needs 4 - 5,000 rpm to overtake in these circumstances and will pull from 3,000 through to 5,000 easily.  Pleased to say that we had a run out today and normal service has been resumed.  Guess it may have been down to some poor quality fuel as suspected.   
Good news there. I hate getting bad fuel.

Sometimes on the road you have to take what is there no matter what.

Wish I could get away with selling a mediocre product at a very high price and not have to worry about anyone doing anything to me. 

mcwhirtj
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Re: Acceleration

Post by mcwhirtj »

LAF wrote: The poster who says the best place to be is the last 2000 RPM to red line.  There is NOTHING there from the motor it is done making any power at 7600-7800 RPM.
This is all I am saying - see the chart.  I have an '08, and the max torque band is from just below 6,000 RPM to just above 7500 RPM, which is right up on the edge or red line *8K on my '08).  So the max torque band occupies roughly the last 2000 RPM before redline - that was what I meant.  That is the band in which my bike "comes alive".  Not saying one should cruise in that band, but if you want to see what it is really capable of in terms of get-up-and-go, and put a really big grin on your face :-) this is the place to be.  If I'm riding hard uphill on a twisty canyon road, or making a move in heavy freeway traffic, I'll drop it down a gear or two to get into this sweet spot and MOVE.  When you get into that zone, the engine is so responsive, and your eyes (had better) on the road not the tach, so one may occasionally rev up to red line - but that is what the rev limiter is for.  The bike is engineered to operate there.  FWIW, IMHO, YMMV, etc.     

I rode a newer LC model, and they flattened out the torque curve with that engine - was quite noticeable, in a good way.  More acceleration at lower RPM.    ~93K Miles on my '08,  but it shows no signs of stopping, so hard to justify a new bike!

Jim
(Dyno chart is from this review in rider magazine:  https://ridermagazine.com/2008/07/09/2008-bmw-r1200rt-moto-guzzi-norge-1200-motorcycle-comparison/

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2008 R1200RT Dyno Resutls.JPG
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