BMW K bikes (Bricks)

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1Back to top Go down    K75 versus bmw k100 on Thu Sep 27, 2018 1:11 am

gabriel


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Hi

I recently purchased a bmw k75s for a very reasonable price.
These are some of my observation over the past few weeks of rid Ng both bikes:
-bmw k75 not as powerful, therefore have to work the gears a lot more.
-riding position. K75s handlebars have a forward riding position. Doesn’t take long for my wrists to develop numbness and pins and needles in my arms.
- K75s smooth engine
-K75s gearbox is very notchy. Gear changes are sometimes difficult. Is this normal for a K75s.
-I was going to sell my k100. I decided to take my k100 to work. I have decided I am not going to sell the bike.
- I now have two k bikes in the shed....Very Happy:D
Any opinions about the K75s and gear changes?

Regards

Gabriel


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;BMW; 1984 BMW k100..frame number 6228?
    

2Back to top Go down    Re: K75 versus bmw k100 on Thu Sep 27, 2018 1:48 am

RicK G

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You will probably find that bad gear changes are the result of a dry input shaft spline which makes the clutch bind a bit or that the oil needs changing in the gearbox.


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"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
    

3Back to top Go down    Re: K75 versus bmw k100 on Thu Sep 27, 2018 2:36 am

Tesla13BMW

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Interesting your description of numbness and pins and needles.  This is exactly what I get with my K100RS.

I blamed it on broken wrists from racing speedway, but, perhaps I should look into changing handle bar position?


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Brisbane, Australia.  '86 K100RS
    

4Back to top Go down    Re: K75 versus bmw k100 on Thu Sep 27, 2018 3:14 am

RicK G

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Get yourself checked out for carpal tunnel syndrome. I had it and got it fixed about 20 years ago and all is good but I cant now ride in that position due to a back injury. Usually it only affects the thumb and three fingers not the little finger.


__________________________________________________
"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
    

5Back to top Go down    Re: K75 versus bmw k100 on Thu Sep 27, 2018 5:45 am

MartinW

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Over the years I have moved my bars up and back. If you do this you will have to extend the dash pad bracket mounts with a piece of aluminium to allow it to be refitted. Also try fitting the oversize foam grips. Some riders can suffer from muscle pump which can cause problems. When you start getting the symptoms see if you are gripping the bars too tightly, if so try and relax your grip. Sometimes a neoprene forearm strap will help. As per Rick lube the gearbox input shaft splines. Other inmates have had success on easing gear changes by placing moly into the gearbox. Some have used moly powder others liquid moly. I use Molybond in a tube which is enough to do both the gearbox and the final drive.
Regards Martin.


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K75s Hybrid
    

6Back to top Go down    Re: K75 versus bmw k100 on Thu Sep 27, 2018 7:38 am

Two Wheels Better

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While I tend to prefer the 'S' position on my Beemers, my red RS has a simple 25mm riser saddle and 50mm bar extenders at either end of the 'bars. As well, there are simple aluminium tabs riveted to the dash centre pad which allows the pad to sit correctly over the 'bars. I have better leverage & control as well as lessening the amount I have to lean forward. I can ride all day.

Tomorrow I will take pictures to clarify.


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1987 K100RS, '93 K11/K12 hybrid 'Big Block', '09 K1300GT, '07 K1200R, '04 R1150RT, '95 R100 Mystic, '77 R75/7.
Have we accomplished half of what we dreamt we would? There may still be time.
    

7Back to top Go down    Re: K75 versus bmw k100 on Thu Sep 27, 2018 9:36 am

Point-Seven-five

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I use Moly powder in my gearboxes which helps make the shift forks move more easily in the drum's grooves.  I also have the clutch splines lubed with a light film of HondaMoly.

Clutch technique also seems to help shifting on my bikes.  Pulling the clutch all the way makes the shifts harder than just a quick fan synchronized with the shift lever.


__________________________________________________
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
    

8Back to top Go down    Re: K75 versus bmw k100 on Thu Sep 27, 2018 4:14 pm

Woodie

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"Pulling the clutch all the way makes the shifts harder than just a quick fan synchronized with the shift lever."


I've noticed this also but why does it work this way?  Just curious.


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1985 K100RT
52667
    

9Back to top Go down    Re: K75 versus bmw k100 on Thu Sep 27, 2018 4:32 pm

Point-Seven-five

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@Woodie wrote:"Pulling the clutch all the way makes the shifts harder than just a quick fan synchronized with the shift lever."


I've noticed this also but why does it work this way?  Just curious.
I suspect that a bit of clutch drag helps keep the internal thingies moving and helps stuff engage.(apologies for the technical jargon)


__________________________________________________
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
    

10Back to top Go down    gear changing on Thu Sep 27, 2018 5:12 pm

redrockmania

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Gabriel - Two addition things are worth investigating. On the K75 check out the pedal and linkages for your gear shift mechanism. Rose connectors for example can wear to the point of needing replacement. 
Is everything comparatively tight, lubricated and moving smoothly and not sloppily. Also check if the angle of the gear lever to the foot peg suits your foot when on the footpegs and actuating the lever. I had to make a significant fear lever level adjustment on my Triumph which made all the difference. Also the way you position your upper foot against the ear lever is important. Try taking up all the slack with your upper foot before the change and you may find the change is smoother and quicker.
Finally different footwear sizes can significant change how smoothly the changes are. Heavy adventure boots position the top for your foot very differently to a normal pair of shoes...Things to consider.

    

11Back to top Go down    Re: K75 versus bmw k100 on Thu Sep 27, 2018 6:13 pm

Point-Seven-five

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@redrockmania wrote: Try taking up all the slack with your upper foot before the change and you may find the change is smoother and quicker.
There should be absolutely no slack in the shift lever travel.

If you need to remove slack from the travel of the gear shift lever when shifting gears you have a loose grub screw.  Of all the places BMW used that damn red Loctite that grub screw should have been the first, but it was not sealed with it.

Tightening that screw is something a lot of us have had to do.  It is about a one day job and can be done along with a clutch spline lube and replacement of the clutch o-ring.  It's also a good time to do things like cleaning the gear position indicator switch and lubing the clutch operating arm. 

If the grub screw is loose it's only a matter of time before it backs out enough that shifting is difficult if not impossible.  The difference in shifter operation when it is tightened is amazing.


__________________________________________________
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
    

12Back to top Go down    Re: K75 versus bmw k100 on Thu Sep 27, 2018 10:59 pm

gabriel


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Hi
Rick, your comment about about the inputs shaft splines made me think about my bike.
I decided to stop riding the K75s for now until I can check the splines.
I replaced the transmission oil but no improvement.
Regarding the loose grub screw, it is possible to rectify the problem without dismantling any of the gearbox internals.
Thanks


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;BMW; 1984 BMW k100..frame number 6228?
    

13Back to top Go down    Re: K75 versus bmw k100 on Thu Sep 27, 2018 11:17 pm

RicK G

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No it's head down arse up into the internals unfortunately.


__________________________________________________
"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
    

14Back to top Go down    Re: K75 versus bmw k100 on Sun Sep 30, 2018 9:34 am

Point-Seven-five

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That grub screw is the initiation into the serious brick owners society.


__________________________________________________
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
    

15Back to top Go down    Re: K75 versus bmw k100 on Sun Sep 30, 2018 11:48 am

duck

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It is possible to make minor adjustments to the angle of the handlebars and also rotate both the clutch and throttle perches to what works best for you. Be careful not to over tighten screws for the clutch and throttle perches.

Master Yoda Riding Position:
http://bmwsporttouring.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=2766&page=1

K75s do need to be run at higher RPMs to get decent torque.


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Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
http://www.ClassicKBikes.com
    

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