BMW K bikes (Bricks)


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1Back to top Go down   Lower first gear Empty Lower first gear Fri Jun 05, 2015 8:26 am

floyd

floyd
Life time member
Life time member
Any gurus out there know...?

Out of the plethora of gearboxes BMW have made....will any of them offer a lower first gear that will go into a K100 gearbox?

Would like to have more ability to craaaaawl along without working the dry clutch so much.


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K100 with lots of K1100 bits - mongrel of a thing...
    

2Back to top Go down   Lower first gear Empty Re: Lower first gear Mon Jun 08, 2015 4:05 am

K75cster

K75cster
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If you haven't used the 3.2:1 F/D from a K75, then that would be the 1st port of call.


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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.
    

3Back to top Go down   Lower first gear Empty Re: Lower first gear Mon Jun 08, 2015 4:38 am

floyd

floyd
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K75cster wrote:If you haven't used the 3.2:1 F/D from a K75, then that would be the 1st port of call.

Cheers mate,

Soooo....This FD would have a lower rotational speed for a given engine rpm - correct?

Thanks for that one...obvious port of call as you say.


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K100 with lots of K1100 bits - mongrel of a thing...
    

4Back to top Go down   Lower first gear Empty Re: Lower first gear Mon Jun 08, 2015 4:45 am

charlie99

charlie99
VIP
VIP
I have a feeling that all the ratios in the gearbox are all the same Floyd

the diff is the clue

unless you can do some magic in one of the similar r series boxes for first gear ....look for any monolever series for investigation is my guess ....twb and some others like the us based r series  mob might have some additional information ...swap gear sets for first ?


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

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
1987 k100rs ########   "Red"  - (red sports rs TWB style )
1989 K100rt #009637   "Black Betty"  (naked rt ala Nigel , now sporting an rs main fairing )
    

5Back to top Go down   Lower first gear Empty Re: Lower first gear Mon Jun 08, 2015 4:59 am

floyd

floyd
Life time member
Life time member
charlie99 wrote:I have a feeling that all the ratios in the gearbox are all the same Floyd

the diff is the clue

unless you can do some magic in one of the similar r series boxes for first gear ....look for any monolever series for investigation is my guess ....twb and some others like the us based r series  mob might have some additional information ...swap gear sets for first ?


Thanks Charlie....Was hoping TWB would chime in with a part number hehe. 

The 75 fd seems like a good idea...but will obviously effect the ratios across the board, rather than just 1st....that may be a good thing tho....my k loves to sit at 130-140kmh...just seems like thats where it wants to be....which gets me in trouble Wink

I was a postie for a while, and the training they gave me was some of the best motorcycle riding instruction ive ever had. Anyways....we had to craaaaaaawl along so slow. The test was something like we had to ride 10m in 30secs without putting our feet down. and had to do turns on the spot at full lock for a while. Was good fun...

Anyways, the K dont like to crawl Mad


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K100 with lots of K1100 bits - mongrel of a thing...
    

6Back to top Go down   Lower first gear Empty Re: Lower first gear Mon Jun 08, 2015 5:03 am

charlie99

charlie99
VIP
VIP
um 40 to 240 in 5th gear ...nope they don't like to crawl

giggles


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

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
1987 k100rs ########   "Red"  - (red sports rs TWB style )
1989 K100rt #009637   "Black Betty"  (naked rt ala Nigel , now sporting an rs main fairing )
    

7Back to top Go down   Lower first gear Empty Re: Lower first gear Mon Jun 08, 2015 5:13 am

floyd

floyd
Life time member
Life time member
charlie99 wrote:um 40 to 240 in 5th gear ...nope they don't like to crawl

giggles

Thats flying, not crawling!


__________________________________________________
K100 with lots of K1100 bits - mongrel of a thing...
    

8Back to top Go down   Lower first gear Empty Re: Lower first gear Mon Jun 08, 2015 5:20 am

floyd

floyd
Life time member
Life time member
This graph compares the road speed of the RS, RT and 75 FD's on a K100 gearbox

The lines, from top to bottom, are RS, RT and 75

Lower first gear Ratio_10


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K100 with lots of K1100 bits - mongrel of a thing...
    

9Back to top Go down   Lower first gear Empty Re: Lower first gear Mon Jun 08, 2015 7:08 am

Holister

Holister
Life time member
Life time member
If you do the calculation for 3000rpm as an example there's 3.5kph difference

Your K100RS
@3k rpm in 1st gear @4.50:1
FD ratio @2.81:1
Tyre circumfrence = 2m
Road speed = 28.6kph

Your K100 with K75 FD
@3k rpm in 1st gear @4.50:1
FD ratio @3.20:1
Tyre circumfrence = 2m
Road speed = 25.1kph


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1989 K100RT     VIN  0097367 (naked)  
1996 K1100RS   VIN  0451808
 Lower first gear Austra12    Fuel:  95 Octane
Engine Oil: Nulon Full Synthetic 15W50
Gear Box Oil:  Nulon Synthetic 75W90
    

10Back to top Go down   Lower first gear Empty Re: Lower first gear Mon Jun 08, 2015 10:13 am

floyd

floyd
Life time member
Life time member
Kaptain Holister wrote:If you do the calculation for 3000rpm as an example there's 3.5kph difference

Your K100RS
@3k rpm in 1st gear @4.50:1
FD ratio @2.81:1
Tyre circumfrence = 2m
Road speed = 28.6kph

Your K100 with K75 FD
@3k rpm in 1st gear @4.50:1
FD ratio @3.20:1
Tyre circumfrence = 2m
Road speed = 25.1kph

Thanks for some perspective Kapn Holister....

Having said that...when my current LT (swapped out from the knackered RS when I still had a spares cache...oh the days) packs it in, so to speak, I shall likely swap it out for a disc brake K75 unit....Time to investigate how many splines these units have....as Im also considering a driveshaft and swing arm lengthening and spline numbers are an obvious issue there.

fun stuff  Laughing

I wanna ride this beast to meet that Irish Eccentric mob we read so much about!  Lower first gear 502531


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K100 with lots of K1100 bits - mongrel of a thing...
    

11Back to top Go down   Lower first gear Empty Re: Lower first gear Tue Jun 09, 2015 4:11 am

Rick G

Rick G
admin
admin
All the K75s had a 20 spline drive whether it was drum or disc rear brake.


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"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
    

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