BMW K bikes (Bricks)

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1Back to top Go down   rear master Empty rear master Sat May 03, 2014 6:12 pm

kartooo

kartooo
Silver member
Silver member
on my 85 k100RT between the adjuster stud and plunger for the rear master is a rubber peg with a washer vulcanized to it. it has sheared off about a 1/8 " from the top. looks like it gives some nice gradual/soft type feel to the rear brake. don't want to buy the $65 master rebuild kit for this piece. anybody tried something different in there ? plastic tubing, fuel line,vacuum line etc. looks like you need the button washer on top to mate with the rounded adjuster peg when done...
maybe something harder or firmer would give the rear brake a better feel too. tried to drill a hole in the rubber of both halves and put a small stud in there but there just isn't enough material on the washer end left to do anything with.

rear master 34311410


__________________________________________________
85 k100rt current
04 vulcan 1500 classic sold
07 bonneville black sold
05 fjr1300 sold
04 r1150rt sold
91 k100lt sold
r80rt sold
85 K100 sold
    

2Back to top Go down   rear master Empty Re: rear master Sun May 04, 2014 12:43 am

charlie99

charlie99
VIP
VIP
if someone was handy with a lathe ...wouldn't be hard to turn something up
I think sidecar paul has already done this

might be a good idea to use the search feature to find the article again ??


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

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%Orear master Au-log10

'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
    

3Back to top Go down   rear master Empty Re: rear master Sun May 04, 2014 11:44 am

kartooo

kartooo
Silver member
Silver member
i'm going to take a small bolt, put some O rings on the outside of it to isolate it from the bore, give it a dish shape on top with a large drill bit, put a piece of rubber down in the base of the MC piston to give it some cushion and then cut it to length.
the original kinda looks like a tire plug with a dished washer vulcanized to the top of it. sure is a lot of rubber there to give the pedal a cushy feel. you can see it in the bottom left of my pic.

    

4Back to top Go down   rear master Empty Re: rear master Mon May 05, 2014 12:46 am

RicK G

RicK G
admin
admin
I am not 100% sure on this but I think it's what is called a reaction pad and is used in power boosters on cars.
It prevents a very sudden jar when the brake is applied and may be there to help overcome the jar for the sake of the ABS models.  No guarantees just my thoughts on it.


__________________________________________________
"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 2004 K1200GT 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki
    

5Back to top Go down   rear master Empty Re: rear master Mon May 05, 2014 9:27 am

kartooo

kartooo
Silver member
Silver member
i agree with your logic.
no abs here. being the rear i believe it helps with not locking up the wheel.
gives it more of a gradual apply. i used a drill bit to dish the head of a bolt to copy the washer that was on top of the rubber plug. slid some silicone tubing on it to isolate it from the MC bore. threaded a hard faucet washer on it to give it that cushion between it and MC piston. works well and i'm confident it will stand the test of time. the original sure has a lot of rubber there to do a lot of flexing side to side eventually failing. it only lasted 29yrs.....


__________________________________________________
85 k100rt current
04 vulcan 1500 classic sold
07 bonneville black sold
05 fjr1300 sold
04 r1150rt sold
91 k100lt sold
r80rt sold
85 K100 sold
    

6Back to top Go down   rear master Empty Re: rear master Mon May 05, 2014 9:34 am

RicK G

RicK G
admin
admin
Only 29 years!!!   take it back if you have the receipt. Laughing


__________________________________________________
"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 2004 K1200GT 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki
    

7Back to top Go down   rear master Empty Re: rear master Mon May 05, 2014 9:53 am

kartooo

kartooo
Silver member
Silver member
he did have a 2yr rest in a barn. i'll call him "Grumpy"
i found him up by the NH border. cut a deal with the owner and had to wait about 6 weeks till the snow in his yard melted enough to get him out. he used windshield washer to un freeze the barn door. that was a looooong anxious 6 weeks. i spent a few weeks on cleaning all connections and grounds, changing all fluids, clutch and diff spline lubes, fork gaiters, intake boots etc etc etc. the past month i have put an enjoyable 2k miles on him. he was still a youngster when i found him with only 25k. got 27k now and counting. if i can stop riding him long enough i still have some new fork springs and SS brake lines to install.


__________________________________________________
85 k100rt current
04 vulcan 1500 classic sold
07 bonneville black sold
05 fjr1300 sold
04 r1150rt sold
91 k100lt sold
r80rt sold
85 K100 sold
    

8Back to top Go down   rear master Empty Re: rear master Mon May 05, 2014 3:56 pm

sidecar paul

sidecar paul
Life time member
Life time member
I did try making a solid fitting to replace the rubber block but it made the brake into an 'on/off' switch. Embarassed 

Ultimately, I added a spacer, about 3mm, over the rubber to reduce the squidge but still retain some feel.

Paul.


https://www.k100-forum.com/t3739-mod-to-rear-brake



Last edited by sidecar paul on Mon May 05, 2014 3:58 pm; edited 1 time in total (Reason for editing : link added)


__________________________________________________
'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!
    

9Back to top Go down   rear master Empty Re: rear master Mon May 05, 2014 5:47 pm

kartooo

kartooo
Silver member
Silver member
i did the opposite but same effect.
made a metal peg similar to your's but with a rubber washer between it and the master..
you used the original rubber peg with a metal washer.
my bike came with some new spare parts including the master rebuild kit minus the rubber peg.....
BMW does not sell the peg separate.
my original sheared off. the original has a bunch of rubber sticking out to compress.
we both reduced that amount of rubber to squish
works well now with great "feel"


__________________________________________________
85 k100rt current
04 vulcan 1500 classic sold
07 bonneville black sold
05 fjr1300 sold
04 r1150rt sold
91 k100lt sold
r80rt sold
85 K100 sold
    

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