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twin spark R1150RT vibration


TopazTiger

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TopazTiger

My 2005 R1150RT has a mild vibration. I did a recent valve adjustment/TBS and added grip puppies. It is a little better with Grip puppies but not gone. Also, in 4th-5th gear I can feel it in the seat (Sargeant). 6th gear is fairly smooth but vibes still noticeable after a long ride (BOTH hands get a bit numb). I am not gripping the throttle too tight. Otherwise runs great; all fluids seem to be okay, handles fine. By comparison my '97 R1100RS seems smoother. Any ideas? Thanks in advance.

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Did you check the condition of all four spark plugs? I'd be looking for any indication of a plug not firing correctly and then tracing any elec faults.

See if you can borrow a pair of stick coils from a bike that runs smoothly. See what happens when they're in your bike.

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realshelby

Did the vibration change after the Throttle Body Synch? Throttle body synchronization has a huge effect on vibration. Especially under load. Just sayin.....you might double check on TBS.

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I've syched the TB to spot on in the driveway, and found the bike vibrated after the service when it had been smooth before. I redid the TB sych with the TwinMax on the tank bag so I could look at it under load while riding. There was a slight out of balance which took maybe 1/16 of a turn to bring back to dead on, and no more vibration. And yes, I did stop the bike to make the adjustment.

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My 2005 R1150RT has a mild vibration. I did a recent valve adjustment/TBS and added grip puppies. It is a little better with Grip puppies but not gone. Also, in 4th-5th gear I can feel it in the seat (Sargeant). 6th gear is fairly smooth but vibes still noticeable after a long ride (BOTH hands get a bit numb). I am not gripping the throttle too tight. Otherwise runs great; all fluids seem to be okay, handles fine. By comparison my '97 R1100RS seems smoother. Any ideas? Thanks in advance.

 

Ricorider, you m-i-g-h-t have a vibration problem & again you might not.. Keep in mind the BMW boxer engines do vibrate,, the larger the engine the more the vibration (my 1150 was worse than my old 1100).. Even though the (2 cyl) boxer engine is an inherently primary-balanced engine there are enough other orders of vibration to make the grips buzz at certain engine operational loads & RPM ranges.. There is also an inherent rocking couple shake because of the wide spacing between the crankshaft rod journals due to large cylinders.. Then you have the peak combustion induced firing frequency disturbances.. All in all the BMW 1150 boxer is not a real smooth engine in certain RPM ranges (usually worse around the 4000 RPM range)

 

On the BMW 1200 hexhead boxer BMW tried to calm the peak vibration periods by adding a (single?) balance shaft.. Obviously it only works a little as adding rotational imbalance to correct an inherently balanced engine leads to off-order vibration periods.. My 1200 is no 4 cylinder Honda when it comes to freeway speed bar buzz & foot peg buzz.. I presume BMW engineering decided to trade off some buzzniess in some operational ranges over peak vibration in narrow ranges (just my guess on this one)..

 

In any case BMW boxer handle bar buzz is at it’s worse after a rider tunes into it.. Until you go looking for the buzz you basically ride through the buzz zones & pay no attention,, once you tune into a problem you tend to hone right in on it every time you feel it.. A tight grip on the bars really makes it worse & much more annoying.. On my 1200 hexhead the factory cruise control is a big help in the bar vibration department as it allows a very relaxed bar grip & a chance to rest the right hand as you ride..

 

As mentioned above verify the TBI balance is spot on & the valve settings are in the ball park,, but those are just minor contributors to the bar or footy peg buzz as most of the vibration you feel is mechanical.. Go over ALL the engine mounting bolts & chassis bolts,, look for anything loose in the chassis,, make darn sure the center stand isn’t contacting the catalytic converter (gives both an audible buzz & frame transmitted exhaust induced buzz,, sort of surround sound if you will).. Make sure the muffler attachment is tight & nothing loose in the exhaust system or mounting.. Check the air intake snorkel for grounding out & make sure the air box is tight..

 

If all up to snuff fastener & TBI balance wise,, all 4 spark plugs are working (this is difficult to check for) then my suggestion would be to just ride the bike & think about other things,, if like most BMW boxer vibration issues your engine disturbance will diminish as you quit paying attention to it.. Kind of like a squeak in a car,, it usually doesn’t bother the driver UNTIL someone else points it out then it becomes an irritating issue..

 

If you still are bothered by bar buzz sometimes adding heavier bar end weights helps the bar buzz (it helped my last 1150RT quite a bit)..

 

Also remember different riding gloves can have an effect on bar buzz feel.. My bar buzz always seemed to bother me more in the spring & early summer when I change from thick winter riding gloves to thinner summer gloves..

 

 

Twisty

 

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TopazTiger

Actually, the vibration did get more noticeable after the TBS/valve adjustment. (Eureka?) That could be it and fairly simple to check out. If only it would stop raining here in Boston I could get her outside for a test ride and fuss with it.

 

I know that the stick coils and the spark plugs are fairly recent. Interesting thought about riding it with the Twinmax hooked up and then stopping for micro adjustments (kind of like adjusting the suspension).

 

This is my 3rd beemer and 2nd oilhead so I am used to vibey twins. Even my R65 didn't leave my hands numb like this.

 

I'll try the areas mentioned and post an update. Thanks guys! I appreciate the collective wisdom.

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It is a little better with Grip puppies but not gone ... BOTH hands get a bit numb

 

Try heavier bar-end weights.

 

I got numb hands when I bought my 2003 RT used. A good valve adjust and TBS, combined with the heavier bar-end weights, put an end to the problem.

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