BMW K bikes (Bricks)


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1Back to top Go down   Is this an acceptable alternative? Empty Is this an acceptable alternative? Sun Mar 09, 2014 4:07 pm

JGT

JGT
Platinum member
Platinum member
Last week dismantled and replaced leaking rear drive oil seal on the K75. For some inexplicable reason could not find the correct allen key to remove the 8 bolts securing the cover plate. I found that a Torx bit was an excellent fit in the cap screw and thus used it to dismantle and rebuild the drive unit. This left me wondering if a Torx bit, that is a good fit in a cap screw is an acceptable alternative or is it preferable to use the correct size allen key? Is there a correlation between Torx sizes and Metric allen keys? Out of interest what size allen key fits these cap screws? I meant to check before assembling back to bike, but forgot. john


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1992 K75
    

TacKler

TacKler
Life time member
Life time member
The correct size is 7mm.  I bought a 3/8 drive impact socket version just for that job. 

As for Torx* bits I would use one in an emergency only.  Essentially with the design of the Allen head bolt you are after surface area contact between tool and fastener.  Max contact area is best, and a clean bolt head as well, so try and clean any grunge out first. 

The engineers can probably drone on for hours about design of the bolt, torque value, pitch and all that stuff but for me the main concern is undoing the little sucker, first time.  🤡 

Dave.


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Red 1991 K75S
    

Rick G

Rick G
admin
admin
Why do BMW make it a 7mm head? Because they can Please don't ask why because I seriously doubt that even BMW could give a sensible explanation. They would without doubt give you large amounts of waffle and no ice cream.

As for using a torx bit it's not the best way but if needs be and it doesn't damage the head then all's well.
The first time I did a drive I had to buy a 7mm bit from my local auto shop $$$$$$$$$$$$$$$$$$$$$$$$$$$$$.
I have a very large collection of allen keys and yet no 7mm so they are not a common size.


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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
    

4Back to top Go down   Is this an acceptable alternative? Empty Re: Is this an acceptable alternative? Sun Mar 09, 2014 11:13 pm

MikeP

MikeP
Life time member
Life time member
Odd. Perhaps it's an antipodean thing? Every allen key set I have includes a 7mm.


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1992 K1
1993 K1100R (used to be an LT)
    

5Back to top Go down   Is this an acceptable alternative? Empty Re: Is this an acceptable alternative? Mon Mar 10, 2014 12:59 am

Rick G

Rick G
admin
admin
I have a set that was in a plastic roll till I unrolled it and then swept all the small bits of plastic up and had a look at the keys and from what I could see of the fragile roll there was a 7mm in it but it apparently went walkabout some time ago.


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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
    

TacKler

TacKler
Life time member
Life time member
MikeP wrote:Odd. Perhaps it's an antipodean thing? Every allen key set I have includes a 7mm.

Perhaps when the ship passes the equator and it turns upside down, the 7mm says to his mates in the tool roll, "Bugger this.  I'm outa here". 

The poor chap then lands on his head, knocking himself unconscious, and when he wakes up, can't remember where he is.  By this time the ship is heading back to BMW land, so the poor little bugger jumps ship at the next port.  He then lives happily ever after in some backward tropical paradise.   Is this an acceptable alternative? 177381 

RIP (Rust in Peace).


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Red 1991 K75S
    

K75cster

K75cster
Life time member
Life time member
What a loverly story, You and rick should get together and tell stories, I'm sure Rossco will forget the scones and drift off to KK land instead


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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.
    

JGT

JGT
Platinum member
Platinum member
Ah That explains it. My set does not include 7mm, nor I notice does the BMW tool role. John


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1992 K75
    

xpc316e

xpc316e
Gold member
Gold member
Perhaps it was designed by the same chap that used to work for Shimano and used a 9mm set screw to anchor the cable on a bicycle rear derailleur?  Why would anyone use such an odd size?  It is the only thing you'll find on bicycles with a 9mm head.


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VIN 0191428, 1991 K100LT, formerly owned by Lancashire Constabulary. This old warhorse is now 'out to grass' and living in retirement in Suffolk, where it will be showered with appropriate love and care.

VIN 6459609, 1992 K1100LT, another ex-Police machine, even though she now looks like she is a former fire engine.
    

10Back to top Go down   Is this an acceptable alternative? Empty Re: Is this an acceptable alternative? Sat May 24, 2014 3:49 pm

billtr96sn

billtr96sn
Silver member
Silver member
You can get heavy duty 7mm allen keys, they were used on a lot of car brake calipers, notably Ford MkV Cortinas and possibly Sierras.

They come with the longer end encased in plastic.

Found them on Ebay
http://www.ebay.co.uk/itm/SYKES-PICKAVANT-FACOM-7mm-HEX-KEY-WRENCH-BRAKE-TOOL-/380912130643?pt=LH_DefaultDomain_3&hash=item58b021da53



Last edited by billtr96sn on Sat May 24, 2014 3:55 pm; edited 1 time in total (Reason for editing : Added Ebay link)


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Something witty is supposed to go here... help!! Is this an acceptable alternative? Uk-log10
http://www.billsbikechat.co.uk
    

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