BMW K bikes (Bricks)


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1Back to top Go down   transmission query Empty transmission query Wed Jul 17, 2019 6:37 am

frankie177rg

frankie177rg
New member
New member
Does the 85 K75 transmission have all the gears rotating on the mainshaft or are all 5 gears fixed... My curiosity is whether or not you could install a taller 5th gear without touching any of the other gears or the final drive. BMW seems to like having the top two gear ratios ridiculously close to each other for some reason. I've always wanted very tall top gears on all my vehicles (2-wheel, 4-wheel, etc.) As an example, I have a Honda XR650L DP bike that I'm gonna change the 5th gear from an 0.84 to an 0.80 ratio. Is there anyone in the world who knows of something similar for this K75? The 5th gear on the K75 is 1.66, while the 4th gear is 1.88. If I could obtain a 5th gear that was more like 1.5, or even 1.4 I'd be a very contented rider.Thanks, Frank

    

2Back to top Go down   transmission query Empty Re: transmission query Wed Jul 17, 2019 9:18 am

Rick G

Rick G
admin
admin
Put a K1100 gearbox in they have a 1.61 top gear and a K100RT/LT rear drive which makes a big difference. However just let them rev they do it willingly and changing gear ratios will do little but drop the revs a bit.


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 1999 K1100 LT with a Big Block 1200
    

3Back to top Go down   transmission query Empty Re: transmission query Wed Jul 17, 2019 11:12 pm

Point-Seven-five

Point-Seven-five
Life time member
Life time member
What RickG said.

These engines have been designed and tested to run non-stop at full load at redline for 24 hours.  They love to rev.

When I got my first K bike I was constantly reaching for 6th gear; a few years and several thousand miles later I now find myself doing 65mph on the interstate in 4th.


__________________________________________________
Present: 1991 K100RS "Moby Brick Too"
 
Past:
1994 K75RT "Ilsa, She Wolf of the SS"
1988 K100RS SE "Special Ed"
1994 K75S "Cheetos"
1992 K100RS "Moby Brick" R.I.P.
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

4Back to top Go down   transmission query Empty Re: transmission query Thu Jul 18, 2019 2:23 am

duck

duck
Life time member
Life time member
Buy a Toyota Camry. They love to run at 2500 RPM.


__________________________________________________
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
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
98 Taxi Cab K1200RS
14 K1600GT
http://www.ClassicKBikes.com
    

5Back to top Go down   transmission query Empty Re: transmission query Thu Jul 18, 2019 5:23 am

Crazy Frog

Crazy Frog
admin
admin
duck wrote:Buy a Toyota Camry. They love to run at 2500 RPM.
And they suck more gas than a K100. Very Happy


__________________________________________________
transmission query Frog15transmission query Logo2101986 k75, 1985 K100rt, 1985 K100rt/EML GT2 sidecar, 1999 K1200lt/Hannigan Astro Sport sidecar.
    

6Back to top Go down   transmission query Empty Re: transmission query Thu Jul 18, 2019 7:20 pm

92KK 84WW Olaf

avatar
Life time member
Life time member
Crazy Frog wrote:
duck wrote:Buy a Toyota Camry. They love to run at 2500 RPM.
And they suck more gas than a K100. Very Happy
Even worse they only move the body.
A K moves the soul as well.


__________________________________________________
1992 K100LT 0193214 Bertha Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red 578 bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 689 58,645 now 106,950 miles Deceased.
1983 K100RS 0011157 Fricka 606 Alaska Blue 29,495 miles Damn K Pox Its a Bat outta Hell Now 58,200 miles. 
1996 K1100LT 0233004 Lohengrin Mystic Red 38,000 miles currently 51,800 miles.
1983 K100RS 0004449 Odette R100 colours 58,000 miles. Sprint fairing now 63,390 miles

Past:
1968 Yamaha 80 YG1
1971 Yamaha 125 YAS-1
1968 Honda 125 SS
1970 Honda CD 175
1973 Honda CB500-4
Honda CX 500
    

7Back to top Go down   transmission query Empty Re: transmission query Thu Jul 18, 2019 7:30 pm

Dai

Dai
Life time member
Life time member
If you're worried about stressing the engine/gearbox, Mick Walker's 'K-Series Motorcycles' states in it somewhere that the drive train was designed and tested to run at somewhere in the region of 175bhp.

Guess that's how Luftmeister got away with fitting turbochargers without modding the guts of the engine.


__________________________________________________
1983 K100 naked upgraded to K100LT spec after spending time as an RS and an RT
1987 K100RT
Others...
1978 Moto Guzzi 850-T3, 1979 Moto Guzzi 850-T3 California,1993 Moto Guzzi 1100ie California
2020 Royal Enfield Bullet 500
    

8Back to top Go down   transmission query Empty longer 5th Mon Jul 29, 2019 1:47 am

Phil Moser

Phil Moser
active member
active member
frankie177rg wrote:Does the 85 K75 transmission have all the gears rotating on the mainshaft or are all 5 gears fixed... My curiosity is whether or not you could install a taller 5th gear without touching any of the other gears or the final drive. BMW seems to like having the top two gear ratios ridiculously close to each other for some reason. I've always wanted very tall top gears on all my vehicles (2-wheel, 4-wheel, etc.) As an example, I have a Honda XR650L DP bike that I'm gonna change the 5th gear from an 0.84 to an 0.80 ratio. Is there anyone in the world who knows of something similar for this K75? The 5th gear on the K75 is 1.66, while the 4th gear is 1.88. If I could obtain a 5th gear that was more like 1.5, or even 1.4 I'd be a very contented rider.Thanks, Frank
I'm busy looking into R1200C gears ( 2,54 ratio ) onto my K. I've found an R1200C bevel drive for sale but I doubt it'll all fit, so does anyone have just the gears ? If I get it right, my 2,82 ratio will probably go to my brother in laws' K75R, and them we'll see what he says about that.

    

9Back to top Go down   transmission query Empty Re: transmission query Mon Jul 29, 2019 2:51 am

duck

duck
Life time member
Life time member
Between a K75 and the four cylinder Ks the only difference in the transmission is 5th gear where the K75 is 1.67 and the 4 cylinder Ks are 1.61 - a little less than a 4% difference.

If you want the tallest final drive gearing that is sure to fit then you should convert the K75 to paralaver and use a K1 final drive which is 2.75. (33/12)

(But you'll end up with a really slow K75.)


__________________________________________________
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
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
98 Taxi Cab K1200RS
14 K1600GT
http://www.ClassicKBikes.com
    

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