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Very good question and I know what I’m about to receive ….. an FJR. But trust me, this pulsating isn’t normal on any bike.
Perhaps there is someone in your area with an RT who could compare how yours is compared to theirs, personally do not see how windshield, Fender Extender or crash bars can cause symptoms.
 
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‘19 RT and about 5-6 others in the garage.
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It sounds kind of silly to ask, but does this occur on all roads? Consistently? The road surface in front of my house will create a horrible roaring grinding noise with some, not all, motorcycle tires. It scared the crap out of me once after rebuilding a bikes transmission.
 

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Discussion Starter · #25 ·
UPDATE: Wife, luggage, fender extender, hugger all removed and it’s still pulsating/vibrating away. Very noticeable in 6th gear at a steady 4000rpm @ 72mph (on the clock)
It’s now booked into the dealer for next month, so that will be interesting.
 

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UPDATE: Wife, luggage, fender extender, hugger all removed and it’s still pulsating/vibrating away. Very noticeable in 6th gear at a steady 4000rpm @ 72mph (on the clock)
It’s now booked into the dealer for next month, so that will be interesting.
There is no problem, you exceeded the maximum speed limit of 70mph. That vibration is telling you to slow down. Ok, had to have some fun. I just hope you can get the same vibrations at 70 or below. Dealers sometimes will tell you that they can't test ride a bike above the legal speed limit. I saw this many years ago where a young kid with a sport bike complained of wheel vibrations at high speeds. I can't recall the speed he mentioned but it was way above the legal limit. The tech told him we can't rest ride your bike at those speeds. The kid was upset and clueless as to what he was actually asking the tech to do on a test ride.
 

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Discussion Starter · #27 ·
If you noted I put (on the clock) the true mileage as per the sat nav was 69mph. But thanks for your input
 

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I’ve just got my very first BMW, a 2020 1250 RT and it’s driving me nuts. It’s brand new, now with 1,300 miles on the clock and at anything above a steady 3500rpm in 4th 5th or 6th gear it has a “pulsating” buzz which comes through the seat and you can also hear the hum hum hum (hard to explain) The Rev counter is steady, the speed is steady without and engine surging but it’s very obvious and mega annoying.

Has anyone experienced anything similar? Any suggestions as to what if May be? Should I be concerned?

TIA
I have a 2016 1600RT, I was getting a vibration and my mechanic put beads in the tires, instead of balancing them. Immediately took away the problem. Sorry I don't know what the beads are called
 

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You have been describing this as two frequencies that are close to each other (i. e. a beat frequency), but related to engine rpm. My first guess would be that the alternator rotor is out of balance and that the alternator rotor operates at an almost exact multiple of the crankshaft speed. Loosening the belt would radically change the vibration pattern.

Digging further though-could your tires have become cupped? Did the vibration start when the bike was new, or after a few miles? Unless oyu are a very aggressive track driver I would discount that.

A beat frequency would be a hhhh-uuuu-mmm-(space)-hhhh-uuuu-mmmm-(space)-hhhh-uuuu-mmmm-(space)-hhhh-uuuu-mmmm-(space)-hhhh-uuuu-mmmm-(space) etc .? What is the repetition rate (cycles per say number in a minute) of the spaces?

Can you record the vibration time history on a cell phone? My Samsung S-10 for example could do it.

If it is an out of balance front wheel, wheel hop frequency of the front tire should be about 27 Hz, and probably lower at lower tire pressures. You should be able to at least statically balance the wheel after removing the brake pad assembly. If the vibration (and BTW guys, all vibrations are harmonic) seems to be particularly rocking the handlebars, that would call for a dynamic balance job. Unlikely tho is my guess.

If the rear tire is out of static balance, that wheel hop frequency is lower maybe 20 Hz. Tires could be eliminated by reducing the tire pressure to say 15 psi, but be careful!

Frequency estimates are hard for JQPublic. I wish I could ride it.

A retired MechEngr w a lot of vibration experience.........
 

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'17 RTW; Cobalt Black; Illium barbaks and crash bars; Sargent seat, Aeroflow Tall windscreen.
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Spoken at length to the dealer who are saying it could be the aftermarket Screen OR Fender Extender OR Crash Bars OR Hugger OR anything else which has been fitted. All of which are ;(

looks like I’ve got a lot of experimenting to do, however the driveshaft does sound very plausible.
What a tool of a response! Did the dealer test ride the bike? Or do ANYTHING except pretend to listen and then blame it on anything and everything he wasn't responsible to fix? That said, you've sure sunk a lot of stuff onto that bike for only 1500 miles.

Test if it's the engine by running it up to the engine speed while the bike is coasting with clutch in. Do you still feel it?

If you think you can do this, put it in neutral from 2nd gear while rolling along about 35mph and then run it to then same RPM with clutch out. Still get the vibe?

If you don't feel it with clutch in and you do feel it in neutral with clutch out, that's flywheel/clutch mechanism related.

To rule out the driveshaft, bring the bike up to the speed that you get the vibe, then pull the clutch and coast. Feel it? If so, it's the driveshaft...or wheel related.

Since the bike is new, it could actually be tire treads. What tires are on this thing? I just tested a GS and was amazed at the tread noise. I didn't hear that on the last GS I rode...with Metzler Tourance...great old tires! This thing was really annoying at about 40mph.

Does the engine run rough? If it does, it could very well be the throttle body synch. It's set at the factory and the dealer is supposed to check it when they set the bike up. Many don't. There are servos to keep the idle smooth, but once out of idle the throttle body synch takes over. I think these 1250s are fly-by-wire now, so I don't know the procedure for fixing this, but it should be easy for a dealer with the BMW computer.

I would get this solved soon or get rid of the bike. You don't want to spend your time and money on a bike that is that annoying. My '17 RT is smooth and near flawless. By far the best of the 4 I've owned.

I have an Aeroflow Tall touring screen on it and a Sargent seat...and this year put on some of those really heavy bar ends. All great, but even before, it never made goofy annoying vibes. When the oil is hot and the motor is a lower speeds, it can sound like there's no oil in it, but it doesn't hurt anything...people call that the "death rattle" but it doesn't really do any damage.

These are great motorcycles...but they have to be working right for you or else better get something else. Don't just put up with this. It could be something serious...so get it looked at if you can't isolate the vibe.

:alien:
 

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This is just a shot in the dark. Do you have Continental tires? I’ve heard of people having problems with them. It seems like a tire or balance problem. Either way don’t baby the motor. The boxer motor loves to be revved. With more miles your engine will get smoother. Interested to know what your problem turns out to be. I do know it’s not an added farkle problem.
 

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I had Continental tires on my ‘14RT and the bike smoothed out considerably when I switched to Michelin. I could see how a fender extension could flutter and cause vibration or a windshield may create turbulence but that doesn’t sound like your issue. I will say this, I’ve had BMW service departments that bent over backwards to help and others that stonewalled denying that there was an issue. I was told repeatedly by a service dept that the transmission issue with my ‘16RS was that I didn’t know how to use a quickshifter even after I explained that the K1300S that I had also had a quickshifter and shifted fine. Went to another dealer and they did sort the shifting issue. Moral of the story is it is not an unusual strategy for BMW and it’s dealers to deny deny deny. Don’t be afraid to try a different dealer if you don’t get any answers.
I also came from an FJR and of course the harmonics feel completely different between the 2 bikes. I can’t speak about the 1250 as I haven’t ridden one but the FJR and 1200RT do vibrate differently. I was surprised when I got back on an FJR after riding my RT how buzzy it felt at 4000rpm. When I rode the FJR regularly including many 1000 mile plus days I never noticed it.
 

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RE: Do you have Continental tires.

My bike's ridden poorly with Michelin PR4 and Metzeler 01 tires, but is as smooth as glass on the 4 sets of Continental Road Attack 3 tires I've gone through.

The issue could still be the tires, but I wouldn't start with "if they are brand X then they're fine" and move on to the next thing. If you think it might be tire related, get them checked out.
 

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I’ve just got my very first BMW, a 2020 1250 RT and it’s driving me nuts. It’s brand new, now with 1,300 miles on the clock and at anything above a steady 3500rpm in 4th 5th or 6th gear it has a “pulsating” buzz which comes through the seat and you can also hear the hum hum hum (hard to explain) The Rev counter is steady, the speed is steady without and engine surging but it’s very obvious and mega annoying.

Has anyone experienced anything similar? Any suggestions as to what if May be? Should I be concerned?

TIA
The hum you called it, could it be more like a wa-hump sound coming from the intake of the air cleaner during the air intake cycle? On my bike its almost like a loud honk if I accelerate hard with the throttle wide open.

I too have a 2020 1250 Rt that made a lot of new (for me) noises I was not familiar with on my 2012 K 1600.

Consider going to the dealer and have a chat with him about what sounds/noises are normal and what might not be normal on a M/C that costs as much as ours has.

He owes you at least that much conversation.
Gary Smith, aka RR Gary
 

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Discussion Starter · #36 ·
Lots of very in depth opinions and advice, many thanks. I’ve now removed everything which isn’t OEM and it’s now booked in with the dealer next week. It’s a pulsating hum which is very obvious so it going to be interesting to hear what they say ………. An update will follow 👍🏻
 

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I’ve just got my very first BMW, a 2020 1250 RT and it’s driving me nuts. It’s brand new, now with 1,300 miles on the clock and at anything above a steady 3500rpm in 4th 5th or 6th gear it has a “pulsating” buzz which comes through the seat and you can also hear the hum hum hum (hard to explain) The Rev counter is steady, the speed is steady without and engine surging but it’s very obvious and mega annoying.

Has anyone experienced anything similar? Any suggestions as to what if May be? Should I be concerned?

TIA
My old 2005 R1200RT did it in 4th gear around 45 or 50 mph. The entire time I owned which was almost 14 years. When I sold it the bike had just under 130 thousand miles on it. I knew it was resonance and never worried about it. I never had an issue with the drive shaft, rear drive or transmission. I also did my own maintenance.

Sometimes I can feel it my current '19 1250RT in fifth gear, ironically, around 45 to 50mph, but it's less than my '05 was. In fact, every boxer I have ever owned has done it to some degree. Those bikes were a 1977 R100/7 (sold with a quarter million on it), 1984 R100RS (sold with 121k on it), 1993 R1100RS (totally with 159k), 1998 R1100RS (sold with 38k) and finally, a 2001 R1150RS (sold with 43k).

The one K bike I ever owned, a 1985 K100RS, never did it. The fact that my R1250RT does it sometimes does not concern me.
 

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I’ve just got my very first BMW, a 2020 1250 RT and it’s driving me nuts. It’s brand new, now with 1,300 miles on the clock and at anything above a steady 3500rpm in 4th 5th or 6th gear it has a “pulsating” buzz which comes through the seat and you can also hear the hum hum hum (hard to explain) The Rev counter is steady, the speed is steady without and engine surging but it’s very obvious and mega annoying.

Has anyone experienced anything similar? Any suggestions as to what if May be? Should I be concerned?

TIA
I had a similar problem on my 2018 R1200GS Rallye from brand new. BMW was no help. My harmonic vibration was from about 32-38 mph with TKC80 tires on, so i thought it might be that. Switched to Shinko 705's and the vibration changed to 42-45 mph. Very harmonic vibration was in handlebars, footpegs and to some extent the seat. Didn't matter what gear I was in, but was more noticeable in the higher gears. I swapped out the aluminum bar end weights with some steel ones I had in my tool chest and the vibration disappeared. Have about 16,000 miles on it now and still no issue. Suppose I should retry the aluminum ones after all these miles to test out the solution, but have not done it yet. Back when I first had the issue I found a couple other mentions of this issue but never any solution.
 

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Hi, I'm new to this forum, i plan on swapping out my GS for an RT soon. This problem i believe is a wheel balance issue, sounds just like my problem but i get it around 45 MPH although its probably there at high speeds but i can't hear it. I noticed it when i started riding in march after i change the rear tire in the winter. Either way its a cheap way of ruling out the tires.
 
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