BMW K bikes (Bricks)

You are not connected. Please login or register

View previous topic View next topic Go down  Message [Page 1 of 1]


GF Wollongong

avatar
Silver member
Silver member
Was about to look (buy?) at a K100 1992 ... used tatty etc but a 4 valve. A quick glance had me thinking that it was an 1100 - didn't really want a K100.

I've got two K100 2 valves. Got the usual 4000rpm vibrations, roasted testicles in summer, dodgy speedo - you know the score

So... what K bike do experienced owners think is the one to get (ignore the K1)?

Preferrably, no vibrations in the motor, reliability, design flaws fixed, etc etc. Don't necessarily need the electric screen.

Ultimately, it would be a keeper ... maybe historic rego when it's more than 30 years old.

And on this note, given that the engine number is found on the side of the (removable) sump, is it possible to use a newer motor in an older bike - but transfer the engine covers and sump from an old bike? ie. all the benefits of the newer engine with the look (and serial number) of the old bike.

Thanks

Guy

    

MartinW

avatar
Life time member
Life time member
One of the K75's no vibrations and handle better than the K100, and not much slower, you can really wring their necks. Fit insulation under the tank and a fuel cooler. The bare 75 the 75C or the 75s in descending order are probably the coolest to ride. The K75RT can get pretty warm. As far as the speedo gears go I'm on my second set at 170,000 K's, do not lubricate them as this causes the gears to degrade. As with most of the K's they are pretty bullet proof as long as you service them and don't leave them sitting. Mine is that reliable it verges on boring.
Regards Martin.


__________________________________________________
K75s Hybrid
    

TacKler

avatar
Life time member
Life time member
Like Martin said, a K75. No need to look any further. cheers


__________________________________________________
Red 1991 K75S
    

charlie99

avatar
VIP
VIP
sad but true the little brother is awesome


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
    

chris846

avatar
Silver member
Silver member
Just getting to know a K75, but I have to say...it's definitely got something...

So how about:
A K1100 frame, chopped in half and shortened by 78mm around the area of the tank rear mountings.

This adapts it to take a K75 engine/gearbox.

Then stick a paralever on it..

With K1100 forks, obviously. And one of tborosak's 'super clean' seat/tail units which could easily (I've used that word, damn) adapt to the shortened frame - and look redhot too..

You get the 1565 wheelbase shortened by 78mm, a good chance of 50/50 weight distribution....

(I need something to do after the K75 MadAss is finished)

    

MartinW

avatar
Life time member
Life time member
There was an article quite a while ago where a guy in NSW had over 1 million K's up on a K75 engine, supposedly never rebuilt. I'll have a look for it but I believe I lent it out.
Regards Martin.


__________________________________________________
K75s Hybrid
    

Laitch

avatar
Life time member
Life time member
@chris846 wrote:So how about:
A K1100 frame, chopped in half and shortened by 78mm around the area of the tank rear mountings.
(I need something to do after the K75 MadAss is finished)
How about this?


__________________________________________________
1995 K75T 68,000 miles
    

Dai

avatar
Life time member
Life time member
Is it just me or was the paralever really just an answer looking for a question? I've never had any trouble with 'jacking up' of the backend of LFB.


__________________________________________________
'83 K100 upgraded to K100RS spec
Others...
'78 Moto Guzzi 850-T3, '79 Moto Guzzi 850-T3 California,'93 Moto Guzzi 1100ie California,
'03 Suzuki Blandit GSF600SK3 (NFS any more because wifey has claimed it)
    

BobT

avatar
Life time member
Life time member
Which is the preferred K bike?That depends on who is preferring it. For me the K100RS 16v is great, but I like the K1200RS better. Having said that I now also have 4 Ducatis in the garage which I prefer to any of the BMWs.

    

brickrider2

avatar
Life time member
Life time member
Heresy!

    

Two Wheels Better

avatar
Moderator
Moderator
I really enjoy riding my K100RS 8V (K589) which I keep Down Undah, and also an '87 standard K75 (K569) owned about ten years ago. The basic reasons I enjoy owning and riding it are that it's not terribly hot in Summer with some very basic mods, has never let me down or left me stranded (there was that one time with the rear lower shocky stud - an easy fix with a local trailer and a competent helping hand), does vibrate a bit at 'steady state' cruising RPM, tho' gets fantastic fuel mileage, doesn't burn any oil between changes, is still subjectively good-looking with its '80s edges and angles, and is relatively easy to work on and to keep maintained. Also, with a few K11 'upgrades' like 35mm TBs, 3 spoke wheels, radial tyres and four-piston front Brembo brakes, she's a roadburner extreme.

Having owned, ridden and loved the K1200RS/GT Brick (K41 series), though heavier, more bulky, far more complicated to service and maintain than a K589 Brick, it's a long-legged torque monster that travels well and has proven to be superbly reliable over distance and time.

But, for me...and this is subjective, with a few objectives thrown in, the newer K12/K13 (K44) series (2004 onwards) is a sweet machine. I feel these are the best of the current tech: comfort is exemplary, handling sublime, reliability unquestioned, power abounds - like a velvet hammer - with the caveat of greater complication and for some, cost to service, and a mild vibration in the very busy upper reaches of the revs. You've gotta have a bluetooth OBD module and a readily available app on your phone (or the much too-expensive GS911 diagnostic tool) to clear codes and re-set service indicator lights. I can sit on any of the three of these I own and spend the entire day in the saddle, un-fussed and in supreme comfort, especially the K1300GT.

I wouldn't give up my old K100RS for any newer model, however. It shines where it counts.

Did I hear someone say heresy!?


__________________________________________________

Bricks: '87 K100RS & Big Block'93 K11 frame, forks, Paralever & gearbox w/'02 K1200RS motor, brakes & wheels.
Other: '09 K1300GT, '07 K1200R, '04 R1150RT, '95 R100 Mystic & '77 R75/7-R100 dual-plugged w/340 cam, big valves, 40mm carbs & exhaust.
    

K75cster

avatar
Life time member
Life time member
@chris846 wrote:Just getting to know a K75, but I have to say...it's definitely got something...

So how about:
A K1100 frame, chopped in half and shortened by 78mm around the area of the tank rear mountings.

This adapts it to take a K75 engine/gearbox.

Then stick a paralever on it..

With K1100 forks, obviously. And one of tborosak's 'super clean' seat/tail units which could easily (I've used that word, damn) adapt to the shortened frame - and look redhot too..

You get the 1565 wheelbase shortened by 78mm, a good chance of 50/50 weight distribution....

(I need something to do after the K75 MadAss is finished)
That is a brilliant idea, replace the K75 frame front with a K100 frame front. Bring the wheelbase back to around the first series GSX750 Suzuki a bike brought out about the same time as the K75. I'd also consider lowering the frame onto the motor/gearbox combo. 30 to 40mm would drop the stock seat to about 760 mm mark, that would make for a diminutive and remarkable bike. It would look normal but as soon as a k parked beside it people would just stare at the difference. Dropping the frame would have to be done whilst converting to a K100 frame front so as to get the geometry right. But what a dazzler that bike would be.

Might I also add that changing the frame like that would change the rear shock mount, It would be pivoted forward by a smidge and maybe the rear wheel travel would go up to 120mm all up?? Either way matching the front suspension travel to the rears would give a bike with a remarkable stance.



Last edited by K75cster on Mon Feb 26, 2018 6:06 pm; edited 1 time in total (Reason for editing : Just added that suspension bit.)


__________________________________________________
Keith - 1987 K75c with r100rt replica fairing and half of a 1984 K100rt 1992 K1100LT a blue one

The Clever are adept at extricating themselves from situations that the wise would have avoided from the outset - QUOTE from david Hillel in Out of the Earth.
    

92KK 84WW Olaf

avatar
Life time member
Life time member
I thought the geometry of the 2V K100 and K75 frames was the same apart from K75 front down tubes altered angle to suit the shorter engine?


__________________________________________________
1992 K100LT 0193214 Alaska Blue 101,000 miles
1984 K100RT 0022575 Baja Red bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Mystic Red 58,645 now 74,700 miles
    

K75cster

avatar
Life time member
Life time member
Olaf, there would be a slight change if yout run the headstock back 78mm and connect it to the frame, the frame slopes backwards towards the shockie mount so it would go up just a bit amidships mate. So alittle wriggling would be needed.


__________________________________________________
Keith - 1987 K75c with r100rt replica fairing and half of a 1984 K100rt 1992 K1100LT a blue one

The Clever are adept at extricating themselves from situations that the wise would have avoided from the outset - QUOTE from david Hillel in Out of the Earth.
    

Point-Seven-five

avatar
Life time member
Life time member
I have two K75's, an RT and an S. I also had a 1992 K100RS16V which got totalled last November and replaced with a 1991 K100RS16V.

Of the three, the K75RT with Russel Day Long saddle is a dream to tour on, but horribly top heavy and clumsy in city traffic and in situations where I am getting on and off. Without the fuel cooler I added, it was nasty hot in summer weather with the heat coming off the tank.

The K75S is light and nimble, IMO as close to a sport bike as any of the classic K's can get. Like the RT, it is smooth and with a comfort seat I can ride it all day. Unlike the RT is has no heat problems for the rider, but has hardly any protection in the rain or on cold days.

The K100RS16V in the last year has become my go to ride for daily commuting and day touring. With a good tune on the throttle bodies, valves and throttle position sensor it is pretty close to the smoothness of my K75's at the same level of tune. Handling is good for an 80's bike and with an aftermarket Fox Twin Clicker it had a plush but very controlled ride.

Where the big difference is is in the 16V power delivery. Where the K75's start to flatten out at 80-85mph the 16V keeps pulling like a freight train until I have second thoughts about talking to a cop(about 110mph) and will probably keep on pulling. Where the K75's are spinning hard at 85 mph, the 16V seems to be loafing along, especially when riding two up. Give it some throttle and it pulls like a beast at almost any speed

Like others, I have never noticed the "jacking" the Paralever is supposed to minimize. If anything, the "jacking force" helps to counteract the weight transfer squat that can occur on hard accelleration. (The only place I have ever seen "jacking" is on videos of bikes on dynos where there is no accelleration weight transfer.) On the other hand, the second u-joint on the Paralever reduces to almost nothing the "pumping" of the shaft back and forth on the final drive splines that causes the wear on the splines. This seems to result in minimal need for spline lubrication.

The RS fairing doesn't seem to throw a lot of heat at me like the RT fairing, yet has enough protection to make riding in near freezing temperatures pleasant. In the rain, it is somewhere in between the S and RT as far as deflecting water from the rider.

The wider wheels on the 16V allow radials that make a big difference on grooved pavement, and enhance the stopping power of the larger brakes. The lower seat height also makes the 16V easier to handle in stop and go traffic.

I have never owned an 8V K100 so really can't comment on the difference from the 16V. All I can say is that the 16V is my personal favorite of the three I own for a general purpose machine.

I have put the K1100RS fairing on my RS without internal baffles. Seems to not be too hot in the summer. While the 1100's have a bit more power, I can't see where I really need it.


__________________________________________________
Present:
1994 K75RT
1994 K75S
1992 K100RS

Past:
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

RicK G

avatar
VIP
VIP
MYTH
The splines do not slide back and forth on the movement of the suspension. Sidecar Paul showed that and I checked using a dial gauge and found about 0.01mm from full up to full down when there is no shock. the centres of the shaft pivot and the swingarm pivot are on a common centre. The splines get like that because of no lubricant to take the hammering that using only one uni joint causes. That is why a high content moly grease works well because it wont squeeze out under load and will remain in place to do the job.
If you don't believe me check it out yourself.


__________________________________________________
"Every normal man must be tempted, at times, to spit upon his hands, hoist the black flag, and begin slitting throats." from Mencken's 1919 Prejudices

Bikes 1993 K1100 LT, 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 for now
    

Point-Seven-five

avatar
Life time member
Life time member
Rick, I agree the splines don't slide due to suspension travel. I used a bad choice of words to describe the rotational speed changes with u-joints. As I understand it, and I could be very wrong, the second joint's speed changes help reduce the effect of the first joint's when the joints are phased properly.

In any event, even if my K100RS16V had a MonoLever drive shaft I suspect I would still prefer it to my K75's for daily riding.


__________________________________________________
Present:
1994 K75RT
1994 K75S
1992 K100RS

Past:
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

RicK G

avatar
VIP
VIP
I really don't know what possessed BMW to use a single uni joint shaft and not have an oil bath like the airheads and then go on to say that the shafts don't need to be lubricated
My Z1300 Kawasaki has the same set up as the airheads (with an oil bath) and at 236K it still is as good as new.


__________________________________________________
"Every normal man must be tempted, at times, to spit upon his hands, hoist the black flag, and begin slitting throats." from Mencken's 1919 Prejudices

Bikes 1993 K1100 LT, 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 for now
    

brickrider2

avatar
Life time member
Life time member
Well, isn't that the same organization that also produced a final drive without a drain plug -- aka sealed for life? Shocked

    

GF Wollongong

avatar
Silver member
Silver member
Thanks for the replies.

So if either a 16V K100RS or 1100 or K75 gives me the puppy dog eyes
AND I've got the story straight for my wife...

Onto reality check time:

Just heard yesterday that my friend's father came off his K75 at about 90km/h approx. Haven't seen the bike. His age is about mid to late 70s. Thankfully no broken bones. Sounds pretty shaken up.

Haven't heard how it happened but the older I get the less likely I am to risk broken bones (leave that for the teens and twenties). I'll just get a long straight section and light up.

Guy

    

chris846

avatar
Silver member
Silver member
Maybe this should be a separate thread, but I'm carrying on with this idea of a K75k ('k' for 'kurz' i.e.short).

Two reasons for a K1100 frame, A: steeper rake (is it 26.5'? - Olaf, I share your understanding of K frame geometries) & B: there's one for sale on ebay at the mo for twenty quid, no reg. document so I won't be reducing the worldwide K population.

Might use some leftover KTM forks and yokes - less offset than the K1100 yokes, but the increased trail will further reduce the wheelbase a bit. Plus, they're upside down, which (apparently) is a GOOD THING.

K75cster - I think lowering the frame would cause a rework of too many components - radiator, airbox etc, and most of all the bellhousing/frame mount. This is a 'cut and shut' which, as you say, has the appeal of looking like a standard K with, erm, a missing cylinder.

I'd already read Laitch's thread about the K75 paralever conversion (so I knew it could be done!), that is so appealing because it takes huge advantage of BMW's unique progressive compatability as models develop. It's as if BMW want us to do this stuff.

Dai - there's a great remark somewhere else on this forum where someone cautions against changing for change's sake - because the 'change' invariably brings about a new problem which then needs a solution too. I found this out for myself when my super-duper K100 with jacked-up rear suspension catapulted me into the scenery when it ran out of rider sag as I did a monster gearchange half way round a bend, and the back end jacked itself up right off the road. Being devoid of any commonsense whatsoever, the obvious and only solution to this self-created two-wheeled disaster, is for me to ride the range from now on with a paralever, which is obviously impossible to crash...

Seriously, I have a R1100s and, to me, the handling is sublime compared with my K. From early days my K liked to weave on long sweepers. I fitted a Koni dial-a-ride (is that a taxi service?) which was supposed to be the bees knees, but probably just made it worse. My K improved no end whenever I carried a pillion, and from that I learned to shift far back in the seat to keep it more stable. I still have to do this despite countless modifications. I can reduce it with monster rebound damping on the rear, but the suspension becomes terrible in other areas if I do that. I'm not the heaviest of riders (12.5 st) and I'm not tall so I sit forwards close up to the tank and lean forward with the low-ish bars. Also, I never have luggage on the rear, maybe all of that doesn't help. None of that is a criticism of the bike, which fits its own envelope perfectly. I'm just in the habit of being a bit off-centre.

    

glennpm

avatar
active member
active member
Hi Chris,

Sounds like an interesting project.

Regarding the weaving, the only time i got that with my K100RS was during spirited riding on sweepers when my head stem bearings were going bad. After I replaced them, it never happened again. I'm a little lighter than you and 6'/183cm tall. I run radials and have a Wilbur rear adjustable shock.

Once I mounted my sidecar, I'd get a little head shake wobble at low speed and ended up putting in Fluidloc dampers from a K75 and an air valve that I can add a bit of pressure in. I need the air with a sidecar passenger. The Fluidlocs were a challenge to put in. I don't notice any drag from them.

Glenn

"Seriously, I have a R1100s and, to me, the handling is sublime compared with my K. From early days my K liked to weave on long sweepers. I fitted a Koni dial-a-ride (is that a taxi service?) which was supposed to be the bees knees, but probably just made it worse. My K improved no end whenever I carried a pillion, and from that I learned to shift far back in the seat to keep it more stable. I still have to do this despite countless modifications. I can reduce it with monster rebound damping on the rear, but the suspension becomes terrible in other areas if I do that. I'm not the heaviest of riders (12.5 st) and I'm not tall so I sit forwards close up to the tank and lean forward with the low-ish bars. Also, I never have luggage on the rear, maybe all of that doesn't help. None of that is a criticism of the bike, which fits its own envelope perfectly. I'm just in the habit of being a bit off-centre."

    

K75cster

avatar
Life time member
Life time member
@chris846 wrote:Maybe this should be a separate thread, but I'm carrying on with this idea of a K75k ('k' for 'kurz' i.e.short).


K75cster - I think lowering the frame would cause a rework of too many components - radiator, airbox etc, and most of all the bellhousing/frame mount. This is a 'cut and shut' which, as you say, has the appeal of looking like a standard K with, erm, a missing cylinder.

I'd already read Laitch's thread about the K75 paralever conversion (so I knew it could be done!), that is so appealing because it takes huge advantage of BMW's unique progressive compatability as models develop. It's as if BMW want us to do this stuff.

Dai - there's a great remark somewhere else on this forum where someone cautions against changing for change's sake - because the 'change' invariably brings about a new problem which then needs a solution too. I found this out for myself when my super-duper K100 with jacked-up rear suspension catapulted me into the scenery when it ran out of rider sag as I did a monster gearchange half way round a bend, and the back end jacked itself up right off the road. Being devoid of any commonsense whatsoever, the obvious and only solution to this self-created two-wheeled disaster, is for me to ride the range from now on with a paralever, which is obviously impossible to crash...
Yes that is true, So even leaving all the frame from the Centre housing back intact, you would just need to remove a small amount of the length of the K1100 down tube to be a neat fit. It could be also managed with a bend in the top bars of the frame bent up to meet all of 6mm at a guess. I doubt 6mm would skew the relationship of the Tank and Battery cover that much. The simplest method would be to accept the rake increase that it would result from just butting up the pipes and welding them neat.


__________________________________________________
Keith - 1987 K75c with r100rt replica fairing and half of a 1984 K100rt 1992 K1100LT a blue one

The Clever are adept at extricating themselves from situations that the wise would have avoided from the outset - QUOTE from david Hillel in Out of the Earth.
    

View previous topic View next topic Back to top  Message [Page 1 of 1]

Permissions in this forum:
You cannot reply to topics in this forum