Page 1 of 2 12 LastLast
Results 1 to 16 of 17

Thread: R1100gs clunky gearbox

  1. #1
    Senior Member
    Join Date
    Jul 2013
    Location
    Grimsby
    Posts
    119

    R1100gs clunky gearbox

    Hi there

    I have a nice r1100gs 52k on the clock fsh, this is my first GS and ism loving it, covered 2k miles in 5 weeks somehow lol.

    To the point, my gearbox can be rather clunky changing gear when the engine and gear oil are up to normal running temperature (5 bars )

    When the engine is cold there are no clunks at all. I've changed the oils and this hasn't made any difference.

    I've read the forum and seen that the later gearboxes were black, has mine got a problem or have I got to live with the problem or have the box stripped and repaired in the inter?

    Any advice appreciated

    Cheers
    Steve

  2. #2
    Senior Member
    Join Date
    Jan 2010
    Location
    Dublin
    Posts
    8,068
    It's they way they are perhaps? You will find its different depending on the oil you put in it, the temperature etc. that's my experience..

    Try preloading the gear lever between changes. That helps. Failing that ride more smoothly.

  3. #3
    Subscriber Click here to find out how to Subscribe
    Join Date
    Jul 2005
    Location
    Darsetshire
    Posts
    1,568
    You have bought a tractor, they all do it.

  4. #4
    Senior Member
    Join Date
    Jul 2013
    Location
    Grimsby
    Posts
    119
    Quote Originally Posted by Seamaster View Post
    You have bought a tractor, they all do it.
    Lol @ tractor :-) I'm sure they weren't clunky out of the showroom ! I'll try the preload , It's the same smooth riding or sporty riding

  5. #5
    Subscriber Click here to find out how to Subscribe
    Join Date
    Aug 2008
    Location
    Cheshire
    Posts
    10,252
    Five years ago when I first got my 1100 (a '94), I use to obsess about the clunky gearchange.

    2nd to 3rd especially sounded like a field gun going off and I tried all sorts to sort it out - 140 weight gear oil, sneaking up on it, pre-loading etc, etc.

    Nothing worked - it's just what they do

    The only thing that makes any difference (on my bike) is that there's a sweet spot at about 4500rpm where, if I'm lucky, I can change smoothly between 1st and third (it almost never happens). The trouble is that it not a natural change point for me in relaxed riding - I tend to short shift and use the torque.

    In the end, you just get used to it and stop wincing in the low gears.

    The only thing I'd caution against is pre-loading as this plays on a weak point in the 1100 gearbox. Pre-loading puts a large, high rev, wearing load on the faces of the selector forks - when they start to wear out, a gearbox rebuild isn't far away.

    It is what it is. It'll never be a jap sports bike gearbox - it's spinning at crank speed and has a dry clutch. Learn to love it

  6. #6
    Subscriber Click here to find out how to Subscribe
    Join Date
    Jun 2006
    Location
    Islandmagee, Co Antrim NI
    Posts
    11,472
    I hope you used GL5 spec gear oil no matter what grade?
    Oh Great and Wise Deity, Grant me the serenity to accept the things I cannot change,

    Courage to change the things I can! And the wisdom to know the difference!

  7. #7
    Subscriber Click here to find out how to Subscribe
    Join Date
    Aug 2009
    Location
    60N
    Posts
    4,081
    A teeny bit of pre loading, bigger boots and two finger on the clutch to pull it half way or less between gear changes... Being positive with your foot is the main thing as missed gears is a bit ugly... Also one little trick from riding power banded two strokes that worked for me... blip the throttle sometimes between up changes as well as down... Works especially for the cavernous 1st to 2nd change as you go through the very positive neutral...

    Seriously, Savanna now Santiago or similar semi off road boots make a hell of a difference as you can't feel all the mechanical bits that come with BM gear changes...

    The main thing that Matt is alluding to is the year of your 11GS M94 gearboxes were the eary GS ones and lasted 94 to 96... M97 gearboxes went from 97 through the early mid 1150 period... M94's have open bearings as of old and taper roller bearings either end of the input shaft...

    M97 were converted to all sealed bearings that will eventually wear but not get jammed like the M94's leading to premature failure... Oilhead gearboxes had alloy selectors faced with titanium (as i remember?) which could chip and wear through with rough use and then wear the alloy quickly so jamming bits of alloy mainly in the tight clearance taper roller bearings... You will only know which one it is by the identifying numbers...

    I know this 'cos i had 3 11GS's of which 2 had ot have gearbox work due to failing taper rollers... You can usually hear them a bit with the clutch out but if the noise increases then it is the tapers getting rough... People like Steve Sciminger are people to speak to then...

    Basically if it's a later 11GS you have less to worry about re gearboxes and the "tractor" tag is fairly normal... And yes, they were tractors out of the showroom too...

    There are reasons why they are tractors and a good read is... http://www.largiader.com/tech/oiltrans/

    The main thing with oilheads is to just ride 'em unless you have something to really worry about... They may not be perfect but they can take some abuse and are good long term bikes once you get the drift...

  8. #8
    Senior Member
    Join Date
    Sep 2003
    Location
    -45.8, 170.5
    Posts
    2,064
    Quote Originally Posted by Ferretboy View Post
    I'm sure they weren't clunky out of the showroom !
    My 1150 was, still is 50-odd thousand miles later. Earplugs are a good idea for all sorts of reasons.

  9. #9
    Subscriber Click here to find out how to Subscribe
    Join Date
    Aug 2009
    Location
    60N
    Posts
    4,081
    PS to my comment above... An 1150 box is totally different in shape and the number of gears but the bearing idea was the same as i remember... They did change things like the width of the gear wheels on mid to late 1150's to slicken things up but with not much effect... I standby to be corrected and tarred and feathered...

  10. #10
    Senior Member
    Join Date
    Jul 2013
    Location
    Grimsby
    Posts
    119
    Quote Originally Posted by Wrigsby1 View Post
    A teeny bit of pre loading, bigger boots and two finger on the clutch to pull it half way or less between gear changes... Being positive with your foot is the main thing as missed gears is a bit ugly... Also one little trick from riding power banded two strokes that worked for me... blip the throttle sometimes between up changes as well as down... Works especially for the cavernous 1st to 2nd change as you go through the very positive neutral...

    Seriously, Savanna now Santiago or similar semi off road boots make a hell of a difference as you can't feel all the mechanical bits that come with BM gear changes...

    The main thing that Matt is alluding to is the year of your 11GS M94 gearboxes were the eary GS ones and lasted 94 to 96... M97 gearboxes went from 97 through the early mid 1150 period... M94's have open bearings as of old and taper roller bearings either end of the input shaft...

    M97 were converted to all sealed bearings that will eventually wear but not get jammed like the M94's leading to premature failure... Oilhead gearboxes had alloy selectors faced with titanium (as i remember?) which could chip and wear through with rough use and then wear the alloy quickly so jamming bits of alloy mainly in the tight clearance taper roller bearings... You will only know which one it is by the identifying numbers...

    I know this 'cos i had 3 11GS's of which 2 had ot have gearbox work due to failing taper rollers... You can usually hear them a bit with the clutch out but if the noise increases then it is the tapers getting rough... People like Steve Sciminger are people to speak to then...

    Basically if it's a later 11GS you have less to worry about re gearboxes and the "tractor" tag is fairly normal... And yes, they were tractors out of the showroom too...

    There are reasons why they are tractors and a good read is... http://www.largiader.com/tech/oiltrans/

    The main thing with oilheads is to just ride 'em unless you have something to really worry about... They may not be perfect but they can take some abuse and are good long term bikes once you get the drift...
    funny you should mention the boots, i do feel too much on the boots im using at the moment. i have got a pair of Abercis motocross boots, but they are so stiff i cant feel rear brake or gear changes very well, i like a tactile feel for the rear ;-)

    i was worried when i saw the comment about GL5 oil for the FD and gearbox, but ive checked and the silkoleanes is infact a GL5 so thats ok.

    mine is a 99 model so hopefully that has the later box, i will keep riding until something goes wrong lol, maybe take it off in the winter and see if it needs a refurb,
    cheers!

  11. #11
    Senior Member
    Join Date
    Jul 2013
    Location
    Grimsby
    Posts
    119
    Quote Originally Posted by Ferretboy View Post
    funny you should mention the boots, i do feel too much on the boots im using at the moment. i have got a pair of Abercis motocross boots, but they are so stiff i cant feel rear brake or gear changes very well, i like a tactile feel for the rear ;-)

    i was worried when i saw the comment about GL5 oil for the FD and gearbox, but ive checked and the silkoleanes is infact a GL5 so thats ok.

    mine is a 99 model so hopefully that has the later box, i will keep riding until something goes wrong lol, maybe take it off in the winter and see if it needs a refurb,
    cheers!
    Just checked, looks like i have according to you great link the later M97 box, interesting read about the input shaft wearing,may look into that as my winter project, maybe have it refurbed for the next 50k lol

  12. #12
    What a waste. Click here to find out how to Subscribe
    Join Date
    Oct 2003
    Location
    S/W London.
    Posts
    61,510
    Why your gearbox rattles and riders new to BMW's have trouble getting their bikes into first gear. From a post i did in 2007.

    I've coloured the paragraph red that maybe of most interest to you.
    Happy reading.


    Read and be enlightened

    BMW Transmissions
    The MO factory visit with BMW supplier Getrag sheds some light upon the darkness of this perpetual irritation.
    CHATTERING TEETH
    ...A splendid new boxer. But still criticized for shifting. How come? MO has a look at the builder of BMW's gearboxes.

    Bitter reproaches for the new BMW R 850 R in MO 11/95. Tester Guenter Wimme addressed the issue of shifting behavior unequivocally: "In the old BMW tradition the great weakness remains: the gearbox. Difficult shifting, long shift lever travel, graunchy shifts between first and second, and still the old tale of woe in finding first at stoplights."

    In that article's conclusion, our (MO's) journalist Wimme recommended that the BMW factory seek out a new transmission manufacturer. As we now find out, shortly after the introduction of the R 1100 RS, BMW was actually in the process of looking... The Bavarians had already contacted gearbox builders in Japan, Italy and Austria. But after ongoing testing of the prototype proposals the source will remain where it has been since 1978: at Getrag in Ludwigsburg, or more precisely, at the Getrag subsidiary, ZWN in Neuenstein/Hohenloh.

    Understandably, the people at Getrag don't like hearing the reproach that they can't build a decent transmission for the prestigious BMW bike, all the moreso since the 3,000 workers of the factory supply the cream of the international automakers with their gearboxes. The list is exceptional: Porsche, Maserati, Alfa Romeo, Alpina Bi-turbo, Jaguar, Ford Cosworth, Dodge Stealth...

    Of course, their biggest single customer is BMW. The complete automotive line, from the 3-series on, is equipped by Getrag, and also the motorcycle line: old Boxers, new Boxers, and K-series. The exception is the F-650 with the Rotax motor. In round numbers, ZWN/Getrag has built about half a million motorcycle transmissions for BMW. Up till 1978, BMW built their own motorcycle transmissions. (...and they didn't shift any better than these... translator's note)

    HIGHER STANDARDS
    Nobody needs to explain the secrets of gear-shaping to the people at Getrag. The know-how of the company, founded in 1935, is incontestable. The in-house development department with its state-of-the-art test center is imposing; the production facilities make an exemplary impression.

    Getrag is proud, and rightly so, of their high automotive product-standard, which applies equally to the motorcycles. All the parts are calculated to take the maximum possible stress from fully-loaded machines, difficult mountain passes and maximum torque. This is a reputation to which we can attest, having performed so many long-distance endurance tests on BMW's. Transmissions of the Bavarian motorcycles are still in spotless condition after 100,000 kilometers and can boast tolerances which would be expected from new parts.

    Nevertheless, BMW's new boxers don't come close to delivering the same standard of gear-changing that has been set by comparable machines such as Honda's ST 1100. What is the dirty secret here?

    O-RINGS AS NOISE-SUPPRESSORS
    A clamor of complaints arose together with the introduction of the new Boxer generation. The clattering noises emanating from the hot gearboxes drove more than just those with delicate hearing back to the dealerships in swarms. Gearboxes were replaced in large numbers, and the public rapidly seized on the image of time-bomb gearboxes. (lit. -"Kaputt-guaranty").

    In fact, Getrag had built a faultless transmission according to their contract, which, through a chain of circumstances derived from the unique technical characteristics (of the BMW motorcycle), created an acoustical nightmare (lit. "defektbombe").

    Analyzed in detail, the truth of the story is revealed. A peculiarity of BMW motorcycle design is that as in an automobile, the transmission is separate from the engine, isolated in its own housing. Between the motor and transmission is the single-plate dry clutch. A characteristic of this design is that transmission noises can clearly be differentiated. In normal Japanese engine architecture the motor and transmission share a common housing. The noises emanating from cam drive, alternator, pistons and transmission blend together, making it difficult to assign exact sources to to the component sounds. The chorus of transmission noises become a section of the overall symphony of mechanical noise.

    Motor and transmission castings on the new Boxer are manufactured by a pressure die casting process, which produce a thin-walled housing. Delicate, thin-walled die castings do not block noise as effectively as the somewhat coarser, thicker-walled sand castings (...as formerly used by BMW — translator's note). The actual source of the annoying gearbox clatter is the gear teeth themselves, as the flanks of the freewheeling gear teeth click against each other, accelerated by by the uneven rotation of the crankshaft. Imagine that you are a piston. Unlike an electric motor, which revolves in a continuous and even rate, the individual rotations of a piston-driven motor are characterized by a series of accelerations and decelerations. The sparkplug fires, "paff", and the piston and connecting rod thrust hard against the crankshaft, which accelerates. Then the piston reaches bottom dead center, losing energy, as simultaneously the cam chain encounters the resistance of the valve springs, which induces a small deceleration in the rate of the crankshaft's rotation.

    At steady, small throttle openings (as in neutral/idle — translator's note) and at minimal combustion pressures (power output) this variation in rotational speed is especially noticeable, moreso as the new BMW boxer is programmed to run at very lean, environmentally optimal mixtures. The resulting surges in rotational speed send a shaking effect through the input shaft to the gear cluster. This is what generates the gearbox rattle in neutral, which is all the more apparent when the transmission is hot and the oil is thin.

    Faced with substantial numbers of customer complaints, BMW had to react quickly. To dampen the clatter the Bavarians resorted to the introduction of rubber o-rings in the gearbox. These were installed between the transmission shafts and the inner diameters of the freewheeling gears. By this simple trick the disengaged gears are always under a slight drag and cannot spin freely on the transmission shafts, their teeth cannot chatter so easily against one another and the noise is noticeably reduced.

    For a self-respecting transmission manufacturer to need to take such a step is something of a fiasco. The efficient operation of the transmission diminished by the o-rings, and the shiftability also suffers.

    However, it happens that the noisy rattling in neutral is also an issue in modern, emissions-optimized automobiles. The manufacturers have resolved the problem with a so-called double-mass flywheel, which dampens the torsional fluctuations before they can reach the transmission input shaft. Such a flywheel cannot be used in the BMW boxer motor, as it would be too heavy and might have durability problems withstanding the higher revs of a motorcycle motor.

    Thus BMW customers of the future will find o-rings in the gearboxes of all the new BMWs, in spite of the fact that the noisy transmissions of the first ('94) series, with the exception of the objectionable neutral noises, were in fact the better-shifting transmissions. These early transmissions, in point of fact, had no pattern of mechanical defects, only an unattractive noise in neutral when the gearbox was hot.

    WHEN FIRST GEAR WON'T ENGAGE....
    The light turns green, you pull in the clutch and step on the shift lever of our brand-new Boxer. It doesn't snick into first, it makes no "clack"...On the dash the big neutral "0" still shows on the digital gear indicator and first gear just won't go in. The "hard cases" just keep standing on the pedal and let the clutch out slowly; the more delicate riders go back to neutral, let the clutch back out and start the process over.

    How do you suppose the BMW automobile developers would react if they were told that the new top-of-the-line 7-series BMW sedans would only go into first gear only 50% of the time? Of course, they would say, "Guys, get your tails right back to the drawing boards!".

    So why did things turn out as they did with the new BMW Boxer? A condition of the contract with Getrag was "No noise when first gear is engaged!" Thus Getrag allowed a "roll-down" time with the clutch pulled in of .8 seconds at operating temperature (note: the time necessary for the free-spinning gears to idle down to a standstill — translator's note). After the introduction of the anti-rattle update, the roll-down time was reduced by the increased internal friction of the o-rings to only .4 seconds. Thus the transmission gears spin down to a standstill very quickly. If the opposing gears have not stopped in just the right position, it is very difficult for the shift dogs to find engagement in their intended slots. Result: the gear will not engage.

    This BMW characteristic is made yet more noticeable by the use of a perfectly disengaging dry clutch. Unlike Japanese motorcycles using a multi-plate oil bath clutch (which always "drags" a little when disengaged — translator's the BMW uses an automotive dry clutch (made by Sachs), which disengages totally, without any clutch drag at all. Thus the BMW clutch provides optimal declutching.

    The Japanese transmission, even with the clutch pulled in, is still under continuous rotation from the dragging clutch plates. The result: first gear engages effortlessly. The disadvantage: epecially when it is cold and the oil is thick, first gear engagement is often accompanied by a terrible grinding noise in many motorcycles. And that is exactly what BMW wanted to avoid.

    CLANKS AND CRUNCHES
    Shifting a BMW transmission requires great concentration. In practice it is a good habit to maintain preload on the shift lever for a moment or two after each shift. Thus one is assured that the gears remain in engagement. This is especially important when starting off and when making the leap from first to second. In general the BMW transmission, even in the higher gears, shifts notchily and unwillingly.

    The Getrag engineers have an illuminating explanation for this characteristic as well. The BMW designers required a minimum of freeplay between rotating parts in the gearbox, so that the "driveline slop", eagerly criticized by magazine testers, would be reduced as much as possible. Minimal rotational play, however, results in more difficult shifting. This is easy to visualize, as the smaller the clearance between the shift dogs on one gear and their respective openings in the mating gear, the more difficult it becomes to find the optimal position for engagement.

    To banish this blemish the Getrag designers developed a two-tiered (stepped) shift dog. The slightly extended, narrower tip of the shift dog easily engages the (now relatively large) opening in the facing gear. When the gears have turned just a little more, the entire shift dog now slides into the engagement slot.

    If a neophyte Boxer owner just nudges the shift lever and feels the tip of the shift dog drop in, it may seem as if the shift has been completed successfully. However, it may happen that under load the gear jumps back out of engagement. The seasoned BMW gear-banger, by keeping the pedal under preload, can feel both the first and second stage of complete engagement take place. Subjectively, the impression the transmission makes is "notchiness".

    Loud clanks and bangs have been inherent in BMW transmissions since the beginning of time. These noises have always been especially "robust" when shifting down from second to first gear. This BMW peculiarity is best explained by the basic mechanical characteristics of the gearbox. The mass of the three-shaft transmission (input shaft w/torsion damper & spring, intermediate cluster & output shafts — translator's note) and large diameter dry clutch inevitably carries a great deal of rotational energy. There are also rather large relative differences in the ratios and speeds of the gears in the lower ranges and at low rpms. Finally, the solid shaft drive system does nothing to dampen the impact of the gears' engagement.

    Thus, the current situation... The question remains: who is guilty of creating this miserable transmission? On one hand it would seem that the bulk of the answer lies buried in the conceptual foundations of the Bavarian Boxer. Tradition is often good for Marketing but not necessarily best when dealing with matters of functionality. On the other hand, the example of BMW/ Getrag shows what can happen when two partners are not sufficiently engaged in communication during the development process... The alloted time suddenly runs out; the World Introduction inexorably arrives, and the dealers, gnashing their teeth, are left to whitewash the shortcomings as best they can. It is lucky that in spite of this the customers are convinced by BMW's offering and continue to buy Bavarian with unbridled enthusiasm.

    Lessons have been learned from this experience by both parties. In the future Getrag/ZWN will lead the transmission development process as the responsible vendor. Hitherto the final development authority rested with BMW. At Getrag there is now a single, coherent design team in place. These are not desk-jockeys, but actual motorcyclists in the flesh. You can already feel the impact! MO has ridden a new prototype transmission in a K 1100 RS. And we can tell you this: total BMW shifting pleasure is coming - and soon.

    SIDEBARS

    1. IN THE PLANS: IMPROVEMENTS TO THE BOXER TRANSMISSION

    In the planning stages: high load roller bearings with fine-particle oil filtration (clean bearings) will replace the previously specified barrel roller bearings on the input shaft. By this means the previously reduced (through the introduction of the o-rings) roll-down time will be increased to approximately 1 second. This will make engaging first gear from a standstill easier.

    Simple shift dogs with slightly increased engagement clearance will replace the stepped shift dogs. The transmissions of the K models have always been equipped with this shift dog design. This measure will improve the shifting haracteristics.

    BMW has recognized that the rider likes to hear an acoustical signal that first gear has been engaged. In the future even a BMW will generate a little noise and produce a perceptible commotion through the shift lever when first gear is engaged. It will all of course be of the highest and most satisfying quality.

    To this end a new dry clutch is being developed with a carefully defined amount of clutch drag when disengaged. This measure will bring the engagement of first gear from a standstill up to the appropriate standard.

    Further detail work on the transmission will make the o-rings superfluous.

    The mentioned modifications will be introduced in series production up through the model year 1997.

    2. CONVERSATION WITH GETRAG/ZWN

    Transmission-Questions: What the builders say. MO spoke to Getrag development engineers Klaus Sommer and Eberhard Schaetzle. Both ride their own privately-owned BMWs. Sommer a K 1100 RS and Schaetzle the new R 1100 GS.

    MO: Are the transmissions of the R models similar to those of the K models, broadly speaking?
    SOMMER: There exists similarity in concept only. For example the gear ratios, shift mechanism and engagement dogs are different on the K model, and the K model even has a different housing.
    MO: Can Getrag-ZWN look back on other motorcycle experience besides BMW?
    SOMMER: At Getrag some time ago we manufactured the Yamaha XS 750 shaft drive system, which was designed by Porsche.
    MO: Getrag produces these transmissions at considerable expense. Forexample the highest-loaded 5th gearset is finely honed to produce the best possible surface on the flanks of the teeth. The rest of the gears are shaved. Do these transmissions still need to be broken in?
    SCHAETZLE: Every fully asssembled transmission goes onto a test stand and is thoroughly tested with hot test-oil. Afterwards the hot oil is extracted and along with it the first wearing-in material.The transmission does not need to be broken in. It can be be fully loaded from the very beginning.
    SOMMER: After the first rides, the o-rings in the boxer gearboxes settle in a little. Then the transmission may shift a little easier. This has nothing to do with wearing in. Only the braking effect of the o-rings is slightly lessened. After sufficient operation and with a hot motor a slight ticking noise in neutral can be audible even with an o-ring transmission. This ticking will be louder when the idle synchronization is not meticulously adjusted.
    MO: What kind of oil recommendation for the BMW transmission can you give us?
    SCHAETZLE: Oil should be seen as an integral part of the transmission. When designing the transmission the load bearing capability of the oil is part of the calculation. We fill the BMW transmissions with SAE 90 GL 5 gear oil manufactured by Fuchs, a brand mainly found as an OEM supplier.
    SOMMER: SAE 90-Oil should be used throughout the whole year. It istrue that in winter the shifting will suffer at first from the thick oil, but it should improve during a very short ride. For those to whom this is disturbing, because they make many short trips, for example, can use 75w90 GL 5 in winter as an alternative. In summer it must be changed back to SAE 90 GL 5.
    MO: How do you regard oil additives?
    SCHAETZLE: Oil additives are always factors which cannot be taken into account when designing and building a transmission. In the best case they don't do any harm. For example, it has not been researched yet how oil additives might react with the new "clean bearings". We therefore rigorously recommend against their use, especially in automotive transmissions. Synchro rings, for example, function only if they can exert some braking effect on the gear wheels. Special extra-slippery additives can result in big damages.

    3. THE BMW BOXER CONCEPT: ADVANTAGES AND DISADVANTAGES

    A QUESTION OF PRINCIPLE — Both Boxer motors and the K series are built on the same fundamental principles at BMW (automotive design — translator's note). The construction principle: crankcase with additional cast bell-housing for the dry clutch and starter drive gear. Bolted up to this is a separate transmission housing containing the final drive output shaft. All the shafts are oriented in the same direction. In the world of motorcycling manufacturers today, only Moto-Guzzi retains an identical construction concept.

    ADVANTAGES:

    Motor and transmission as separate entities may make later repairs more economical, since less labor time is required to service separate components. The separate gearbox can be lubricated with special transmission oil. Thus in principle it should be possible to provide a "lifetime" lubricant. The oil remains clean forever, since there is no wear material from the dry clutch being deposited in the oil (as would be the case with a wet clutch — translator's note). The motor lubricant is not burdened with the wear and contamination of the transmission and clutch. Thus longer oil change intervals can be recommended. All rotating shafts are lying parallel in the same plane, resulting in better mechanical efficiency.

    DISADVANTAGES:

    Noise suppression of the separate transmission and crankcase housings and large dry clutch bell housing is not very effective. The primary drive reduction must take place in the transmission after the clutch. This increases the rotating masses in the transmission. This has an adverse effect on shifting comfort and noise when changing gears. Crankshaft rotation perpendicular to the rotation of the wheels may have an adverse effect on chassis stability. Crankshaft torque reaction is not cancelled by a counter-rotating clutch or similar heavy rotating mass. The motorcycle leans along its long axis under acceleration. This constructions results in a long engine/transmission package. Thus a shorter wheelbase, desirable for good handling, is scarcely possible. Shaft drive vastly increases the unsprung weight of the the rear wheel assembly. This impairs the suspension behavior of the machine. Shaft drive mandates a wide separation of the footpegs. This is not ideal for the seating position.
    _________________
    All your BMW servicing needs at the .gsshop.biz, including 1200 models

    Recommended as an "excellent independant" in Ride magazine 2009.

  13. #13
    Senior Member
    Join Date
    Jul 2013
    Location
    Grimsby
    Posts
    119
    \thanks! that was a very informative read, well done for posting that :-)

  14. #14
    Subscriber Click here to find out how to Subscribe
    Join Date
    Jul 2010
    Location
    London UK
    Posts
    109
    What a refreshing, objective post. I now love my clunks and whirrs even more than before. Bravo!

  15. #15
    Subscriber Click here to find out how to Subscribe
    Join Date
    Jun 2003
    Location
    Swindon, England
    Posts
    4,103
    I guess that makes me a 'Hard case' when selecting first. But then you don't have much time when filtering.

    I will be a good boy and practice the 'Delicate Method'.


  16. #16
    Subscriber Click here to find out how to Subscribe
    Join Date
    Aug 2009
    Location
    60N
    Posts
    4,081
    I read the Steptoe post info a few years ago to and it was one of the best bits of gearbox design info I had read... I remember oilheads 1st coming out and all the complaints about noisy boxes and rebuilds on M93 and it may be seen that the rattle was the only prob and in trying to get rid of it they introduced other probs... Moaning bastard BM riders... What is also interesting as to the "twin effect" is that k boxes were similar but were usually slick as slick and trouble free...

    Also it IJH in the last post, i found that 1st on oilheads and TBH Airheads as well is only really easy to engage without a big fuck off clunk, when the bike is virtually stationary or with a very healthy blip to get 1st to engage relatively drama free... It was totally different to Jap bikes and with the very big 1st to 2nd gap, was very BMW and something you soon get used to...

Page 1 of 2 12 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Anyone attending a Ride Out or Event organised through the UKGSer Forums does so at their own risk.
UKGSer.com or anyone organising an event posted here will not be held responsible in any way for damage or personal injury sustained while attending any such events.

Members attending any such event do so at their own risk.

The text, images, graphics, sound files, animation files, video files, and their arrangement on this Website are all subject to copyright and other intellectual property protection. These objects may not be copied for commercial use or distribution, nor may these objects be modified or reposted to other sites without prior written permission.

Disclaimer: Use or depiction of the BMW logo or trademark throughout this web site is for illustrative and editorial purposes only, and to the benefit of the trademark owner, with no intention of infringement of the trademark.

The UKGSer Forums may include adult content for which it cannot be held responsible. Your use of this website constitutes acceptance of the UKGSER network privacy policy



UKGSer is....

"A vent, a source of info, a source of bullshit, a source of humour and in the coming months, possibly a source of sanity." Big Lad March 2020

"I have always known this community is full good people even if most of you cover it up with piss n vinegar" Chad 2018

"Its about being a grown up hooligan - and if that means a dark visor, remus open pipe and a bit of speeding out of town then all well and good" Kaister 2005