Does yours vibrate at 5000 rpm

[jonesai]

I balanced the throttle cables using a home made manometer filled with fork fluid on my 1999 1150GS ,23k miles following instructions on this site and Haynes manual to the letter.
Can't get them balanced perfect as adjustment is very sensitive, but at 70 to 80 mph (3000 to 4000 rpm approx) E (6th gear) the vibes are acceptable.
Get into the 4000 to 5000 rpm range, which is around 90 to 100 mph, all done on a private road of course..and the level of vibration is unacceptable for comfortable riding or doing the engine much good either.

• is this normal ?
• or am I asking too much of a parallel twin?
• or do I need to balance the cables again maybe using a twinmax?

advice appreciated

 

[davedyer]

My new 1200GS (just 800 miles on the clock) is exactly the same. It's just had it's first service and I've found the vibes are slightly less - probably because of the fresh oil.
Given that it is a 1200cc twin a certain amount of vibes has to be expected (just look at Harleys)
But up to 4.5k you could almost believe you were riding an in-line 4 - it's that smoooooth.
Aparantly they get better with age.
So don't worry.

 

[blues n twos]

My standard 1150 with the lower geared 6th gear was silky smooth at 100mph.

However my 1150 ADV having to rev higher in 6th has noticably more vibes the higher up the revs you go. Very smooth to about 5000rpm which is about 85-90mph. Rev it past that and I wouldn't want to ride at that spped for long as it feels as though the engine is having to work so much harder.

Did yours vibrate badly before you started tinkering ?......

Because there is an old saying on this here site that " if it ain't broke"....

Jon

 

[(RIP) Bin Ridin]

My '02 1150 has a rough patch at about 5,000 revs, not too serious but noticeable, and absent on the 1200. I have a set of Magurit hamdlebars to fit, partly to see if it they reduce the vibes felt at the handgrips.
Bin

 

[turnipbmw]

I was told that BMW's vibrate because the pistons are not opposite each other - makes sense but why did they not use a forked big end like Harley Davidsons if thats the case ?

 

[Blackal]

Forked crankshafts generally take up more space on the crankpin, which requires the pin to be longer, thereby increasing the distance between main bearings which in turn increases the bending forces on the crankshaft.

One could ask on a Harley forum (if you dare ) - why they don't opt for a horizontally-opposed engine (a la BMW) which would reduce their vibration?

Al

 

[davegs]

Paralell twins?

How long have bmw's ben n making paralell twin gs's? paralell twins really do vibrate, sure your not changing into to (sixth gear) too early, i.e below sixty or freferably 70p mph?.
dave ( with an horizontlly opposed twin)GS.

 

[Sween]

Forked big ends

BMWs have two big ends set at 180 degrees so that the pistons move in opposite directions and arrive at the top at the same time. A flat twin with one big end on the crank would shake its self to bits.

 

[(RIP) Bin Ridin]

fixed it for you....

BMWs have two big ends set at 180 degrees so that the pistons move in opposite directions and arrive at the top at the same time. A flat twin with one big end on the crank would shake its self to bits.

just like a H-D does.

 

[nud1e]

good vibrations

all boxers have the vibs in 4000 - 5000 range. balancing the carbs will minimise the vibs, but never remove them. I've found that the setting of the rear shock also has an effect on the apparent vibration. with panniers on, it's acceptable. take the pannier off and don't change the setting of the shock and the vibes are harsh. Keep meaning to play around with this and the rear subframe mountings to see what difference, if any, occurs

 

[Rob Farmer]

Most of the dyno graphs I've seen show the 1150s running very lean at 5000 rpm. The guys who have fitted Techclusion units all seem to be very happy with the smootness of the bikes once they have fitted them...worth a look?

Have you still got the Yellow coding plug fitted in the fusebox? if you have it needs removing and the Motronic resetting (pulling fuse 5).

My 2003 1150 GSA has a lean spot at 5k.

 

[jonesai]

vibration at 5000 rpm

Thanks for the responses

Rob
I will think about the Techlusion.I assume that it enrichens the mixture and hence the vibs decrease?

I still have the Yellow coding plug fitted in the fusebox.It connects nos 6 and 2.
Do you simply remove it and not replace it?
How do you reset the Motronic?

I have a standard exhaust with Cat.

 

[ianboydsnr]

I balanced the throttle cables using a home made manometer filled with fork fluid on my 1999 1150GS ,23k miles following instructions on this site and Haynes manual to the letter.
Can't get them balanced perfect as adjustment is very sensitive, but at 70 to 80 mph (3000 to 4000 rpm approx) E (6th gear) the vibes are acceptable.
Get into the 4000 to 5000 rpm range, which is around 90 to 100 mph, all done on a private road of course..and the level of vibration is unacceptable for comfortable riding or doing the engine much good either.

• is this normal ?
• or am I asking too much of a parallel twin?
• or do I need to balance the cables again maybe using a twinmax?

advice appreciated

i did the same including making my own manometer, but they adjusted untill they were spot on, not tried it since, but it werent to bad at 5000 before if i remember correctly

 

[littleredrooster]

It's better if you balance them under load. Get a set of vacuum gauges and strap them to the bars and take it for a ride on a quiet road watching what happens to the needles as you accelerate. Get them spot-on at 3000rpm upwards and future adjustments will only take a matter of minutes.

 

[Rob Farmer]

Thanks for the responses

Rob
I will think about the Techlusion.I assume that it enrichens the mixture and hence the vibs decrease?

I still have the Yellow coding plug fitted in the fusebox.It connects nos 6 and 2.
Do you simply remove it and not replace it?
How do you reset the Motronic?

I have a standard exhaust with Cat.

The Techlusion has adjustable "steps" that override the EFI pulses to the injector lenghtening their operating time (hence richening the mixture). I'm sure doing a search will throw up more info than my alchohol sozzled brain will ever do


To remove the coding plug just turn the ignition off, pull the little yellow critter out, remove fuse 5, leave for 30 seconds or so, put the fuse back in, turn on the ignition and wind the throttle fully open and closed a few times.

Theres a few fusebox inlays around if you aren't sure whats what in there http://www.ukgser.com/forums/showthread.php?s=&threadid=7564

 

[jonesai]

Thanks to all
Plenty there for me to play with at the weekend if the rain stays off