BMW K bikes (Bricks)

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1Back to top Go down    Now the truth comes out on Thu Jul 11, 2013 9:40 am

RicK G

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After getting some questions as to where the info came from about the K100 and K75 gearboxes having different top gear ratios I did some investigating with the parts book/s
I first got the info on the motobrick site and I questioned it then and was shown copies of the original sales brochures that BMW printed for the North American market and most likely the rest of the world as well.
It stated the K100 as having a top gear ratio of 1.61 - 1 and the K75 was 1.67 - 1. This can not be correct as the part numbers for all the 8v engines K100 or K75 are as follows Drive gear on the input shaft is 23211 451 039 and has 18 teeth that is common all the way through to the end of production of the 5 speed getrag gearbox which was 3/1997.
The driven gear on the output shaft part number is 23211 451 075 and is a 30 tooth gear and is the same right through the production of gear boxes for the 8 valve engines.
However there is a difference in the gearboxes for the 16 valve engines K1 K100 RS 16V and all K1100, the driven gear is part number 23211 461 900 and it is a 29 tooth gear.
So actually the difference is between the 8v and 16v engines not the 3 and 4 cylinder engines.
The ratios are correct but the 8v engines have a 5th gear ratio of 1.67 - 1 and the 16v engines have a 5th gear ratio of 1.61 - 1.

This info has come from real OEM which we all seem to accept as a reliable source for this type of info.


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If everything seems under control then you aint goin fast enough:- Mario Andretti
Bikes 1986 K100RT, 1993 K1100 LT, 1994 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 & 1976 SR 500 Yamaha for now
    

2Back to top Go down    Re: Now the truth comes out on Thu Jul 11, 2013 9:55 am

klompy the grey brick

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I guess I would have to be stating the bleeding obvious but is it not written/stamped on the item?...or even comparison of RPM to miles/kilometres per hour.....just saying.
Although if the part numbers are the same....anyhow 75's are quicker and 100's are faster isn't that right?


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KKlompy
1984 K100RS Silver VIN 0019026 Mitt eine Staintune Zorst.
1997 K1100LT Dark Grey VIN WB1052600W0237453.

Chassis number0019026
Vehicle code0503
SeriesK589
ModelK 100 RS 83 (0502 ( 0503 )
Body typeK 100 RS 83 (0502
Catalog modelECE
Production date1984 / 07
Engine0513)




    

3Back to top Go down    Re: Now the truth comes out on Thu Jul 11, 2013 4:56 pm

sidecar paul

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Hmm, the plot thickens, so why did BMW print this?





Yes, I know it doesn't matter a jot in practice but to be real K geeks we need to have the truth!

Paul.


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'84 K100RS (0014643) (owned since '85), 86 K100RS (0018891) with Martello sidecar (built as an outfit in '88),
'51 Vincent (since '67),'72 Montesa Cota (from new), '87 Honda RS125R NF4 (bought 2015)
....No CARS never ever!
    

4Back to top Go down    Re: Now the truth comes out on Fri Jul 12, 2013 3:53 am

RicK G

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I don't think there really is a plot as such but some numpty that got a thick ear after the second boo boo that was made.
The brochures I saw copies of were fairly much the same as that one so were probably from the same time frame

Like you say no real difference except to the Klovers.


__________________________________________________
If everything seems under control then you aint goin fast enough:- Mario Andretti
Bikes 1986 K100RT, 1993 K1100 LT, 1994 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 & 1976 SR 500 Yamaha for now
    

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