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1Back to top Go down   Four pot Brembos on a K75? Empty Four pot Brembos on a K75? Tue Mar 02, 2021 6:47 pm

gorio

gorio
Silver member
Silver member
I am wondering if anyone has made the swap to the four pot Brembos from the F08's found on the K75 1993 or 94 models.
It looks like the mounting fits but what about rotor alignment ans wheel clearance? Is a fork and wheel change need to go with it?

Thanks


__________________________________________________
1992 K100rs 16v
1997 R1100rt
2006 R1200rt
Past lives
Kawasaki Concours
1976 BMW R90s
1975 Ducati 860gt
1992 Honda VFR750
1985 Honda VF750
1982 Kawasaki 750GPZ
1975 Norton 850 Commando
    

2Back to top Go down   Four pot Brembos on a K75? Empty Re: Four pot Brembos on a K75? Tue Mar 02, 2021 10:00 pm

robmack

robmack
Life time member
Life time member


__________________________________________________
Robert
1987 K75 @k75retro.blogspot.ca
http://k75retro.blogspot.ca/
    

3Back to top Go down   Four pot Brembos on a K75? Empty Re: Four pot Brembos on a K75? Tue Mar 02, 2021 11:04 pm

Two Wheels Better

Two Wheels Better
Moderator
Moderator
My red RS in OZ has four piston Brembos at the front, along with 292mm Suzuki discs with aluminium spacers set behind the discs to appropriately centre the callipers, plus K11 20mm master cylinder, K11 throttle twist assemblage, K11 throttle cable with a modified TB end and eventually K11 35mm TBs. I found it all on eBay, etc., and found the swap much as Robmack describes.

It was worth it, but I enjoy mucking about with this n that in an effort to see if it can be done and perhaps through some (often) misguided idea that change is an improvement.


__________________________________________________

1970 R60/5, OZ '77 R75/7-R100, '85 K100'87 K75C, OZ '87 K100RS, '93 K11-K12 Big Block, '93 K1100RS, '95 R100-Mystic, '96 K1100RS, '98 K1200RS, '00 K1200RS, '02 K1200RS, '03 K1200GT, '04 R1150R'04 R1150RT, '05 K1200S, '06 K1200R, '07 K1200R, '09 K1300GT & 2013 R1200RT-Polizei  - Beemers owned still or sold.

~We all believe what we want to believe in - Rob Dickinson
    

4Back to top Go down   Four pot Brembos on a K75? Empty Re: Four pot Brembos on a K75? Wed Mar 03, 2021 2:38 am

Suzi Q

Suzi Q
Life time member
Life time member
"It was worth it, but I enjoy mucking about with this n that in an effort to see if it can be done and perhaps through some (often) misguided idea that change is an improvement."


Sums it up nicely  Four pot Brembos on a K75? 112350


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Sometimes I'm not really Suzi Quatro.
    

5Back to top Go down   Four pot Brembos on a K75? Empty Re: Four pot Brembos on a K75? Wed Mar 03, 2021 2:50 am

gorio

gorio
Silver member
Silver member
Thanks for the info folks. I am guessing I will need to meaasure it all up and then decide.


__________________________________________________
1992 K100rs 16v
1997 R1100rt
2006 R1200rt
Past lives
Kawasaki Concours
1976 BMW R90s
1975 Ducati 860gt
1992 Honda VFR750
1985 Honda VF750
1982 Kawasaki 750GPZ
1975 Norton 850 Commando
    

6Back to top Go down   Four pot Brembos on a K75? Empty Re: Four pot Brembos on a K75? Thu Mar 04, 2021 4:17 pm

jbt

jbt
Silver member
Silver member
@gorio wrote:Thanks for the info folks. I am guessing I will need to meaasure it all up and then decide.
I have considered that option, but it implies to use the 20mm Magura master cylinder. Very expensive, fragile and rare to find in good condition. A Brembo or Nissin 19mm MC would do the job, but will make you change the throttle and find a solution to fit the switches.
Adding the adaptation needed for discs, does the braking improvement worth the cost and the lack of reliability? Not sure. Genuine K75 brakes are pretty good if they're in good condition.


__________________________________________________
Let us enjoy the transient delight
That fills our fairest day.
    

7Back to top Go down   Four pot Brembos on a K75? Empty Re: Four pot Brembos on a K75? Thu Mar 04, 2021 4:27 pm

gorio

gorio
Silver member
Silver member
My mind went to this because at the moment I have a complete front end as well as the Switch gear and MC from a R1100 sitting here.
The calipers and MC are very much like that on me 92 K100rs4v So it got me to wondering. 
With all of the wild and wonderful things people on here do to these bikes I thought it worth asking. 
The K75 claipers maybe rebuildable which is likely the first choice but if they prove to be beyond repair and the parts I have would swap over without to much trouble it might be worth doing. Sourcing another pair of F08's comes with a fairly high price tag for the current budget. 
It seems i have less motorcycle units to spend then some.


__________________________________________________
1992 K100rs 16v
1997 R1100rt
2006 R1200rt
Past lives
Kawasaki Concours
1976 BMW R90s
1975 Ducati 860gt
1992 Honda VFR750
1985 Honda VF750
1982 Kawasaki 750GPZ
1975 Norton 850 Commando
    

8Back to top Go down   Four pot Brembos on a K75? Empty Re: Four pot Brembos on a K75? Thu Mar 04, 2021 4:36 pm

jbt

jbt
Silver member
Silver member
@gorio wrote:My mind went to this because at the moment I have a complete front end as well as the Switch gear and MC from a R1100 sitting here.
The calipers and MC are very much like that on me 92 K100rs4v So it got me to wondering.
They are the same, so is the MC.
Another option would be to find a K100RS1/K1100 fork and 3 spoke wheels.


__________________________________________________
Let us enjoy the transient delight
That fills our fairest day.
    

9Back to top Go down   Four pot Brembos on a K75? Empty Re: Four pot Brembos on a K75? Fri Mar 05, 2021 12:50 pm

gorio

gorio
Silver member
Silver member
@jbt wrote:They are the same, so is the MC.
Another option would be to find a K100RS1/K1100 fork and 3 spoke wheels.
Thats the ticket then. If the rebuild doesn't take.


__________________________________________________
1992 K100rs 16v
1997 R1100rt
2006 R1200rt
Past lives
Kawasaki Concours
1976 BMW R90s
1975 Ducati 860gt
1992 Honda VFR750
1985 Honda VF750
1982 Kawasaki 750GPZ
1975 Norton 850 Commando
    

10Back to top Go down   Four pot Brembos on a K75? Empty Re: Four pot Brembos on a K75? Sat Mar 06, 2021 12:22 pm

robmack

robmack
Life time member
Life time member
Many years ago when I was researching 4-pot conversion for my bike, I compiled a document from all sorts of Web sources. A link to that research is below:

https://drive.google.com/file/d/1D42exu8qpPn1An3tajpCLVzIf_o_utnh/view?usp=sharing

The parts of interest are highlighted in Yellow.


__________________________________________________
Robert
1987 K75 @k75retro.blogspot.ca
http://k75retro.blogspot.ca/
    

11Back to top Go down   Four pot Brembos on a K75? Empty Re: Four pot Brembos on a K75? Sun Mar 07, 2021 12:24 pm

gorio

gorio
Silver member
Silver member
@robmack wrote:Many years ago when I was researching 4-pot conversion for my bike, I compiled a document from all sorts of Web sources. A link to that research is below:
Thanks robmack. We are fortunate to have people here like yourself that document things so well.


__________________________________________________
1992 K100rs 16v
1997 R1100rt
2006 R1200rt
Past lives
Kawasaki Concours
1976 BMW R90s
1975 Ducati 860gt
1992 Honda VFR750
1985 Honda VF750
1982 Kawasaki 750GPZ
1975 Norton 850 Commando
    

12Back to top Go down   Four pot Brembos on a K75? Empty Four Pot Brembos On a K75 Wed Apr 28, 2021 7:40 am

pugsley

pugsley
New member
New member
I put a pair of four pot front Brembos on my K75 a couple of years ago. I have done about 3,000 miles on them now and would not go back to my old two pot FA08 Brembos, the four pots are excellent. 


My bike is a 1986 K75S with 1993 K75S three spoke wheels fitted. It is a non-ABS bike.


I used a pair of little used EBC MD605 (RS/LS) discs which came off a BMW R100R Mystic, these did not require any further modification or spacing and mounted and aligned fine.


I used a pair of four pot Brembo calipers from a 1998 BMW K1200RS. These did not require any further modification or spacing and mounted and aligned fine with adequate clearance from the wheel spokes. My forks are the 1986 Brembo type, not the later Showas, though I am not sure that would make any difference as the 3 spoke wheel spacers and caliper mountings do not appear to be any different between them. 


The hydraulic brake lines mounted up to the new calipers without any problems. The brake lines were the standard arrangement for the 1986 K75S with two separate hydraulic lines down to each caliper from the splitter under the lower fork yolk.


I tried the first iteration of the modification with the original K75S 13mm bore Magura master cylinder. I found the lever travel too much and the brake feel was poor. I bled the brakes a few times in case that was making the hydraulic ratio problem worse, that was not the problem. So I fitted a 15mm bore Magura master cylinder from the TWIN disc version of the BMW R100R Mystic (part number 32722314022). 


The benefit of using this master cylinder apart from the obvious hydraulic ratio change is that your original throttle grip, mirror and switchgear is retained without any modification. The 15mm master cylinder sorted out the brake lever travel and brake feel which is now very good. I don't suppose that I should have been surprised at this being a good match as this is essentially the same set-up as the R100R Mystics with similar sized twin Brembo four pot caliper pistons, so the hydraulic ratio is the same.




I started out using Brembo 07BB24SA sintered brake pads but these felt too grabby for me and now I am using the EBC FA407 organic pads which have a less grabby and more progressive feel and allegedly reduced disc wear, though I have yet to verify this in practice. I suppose this is really a matter of personal preference.




I hope this is useful. It is one of the best mods I have done to my K75 and thanks to those that did a lot of the donkey work before me.



Last edited by pugsley on Thu Apr 29, 2021 7:28 am; edited 2 times in total (Reason for editing : errors corrected and additional information added)

    

13Back to top Go down   Four pot Brembos on a K75? Empty Re: Four pot Brembos on a K75? Thu Apr 29, 2021 1:03 pm

gorio

gorio
Silver member
Silver member
@pugsley wrote:I put a pair of four pot front Brembos on my K75 a couple of years ago. I have done about 3,000 miles on them now and would not go back to my old two pot FA08 Brembos, the four pots are excellent. 

Thanks for the info Pugsley


__________________________________________________
1992 K100rs 16v
1997 R1100rt
2006 R1200rt
Past lives
Kawasaki Concours
1976 BMW R90s
1975 Ducati 860gt
1992 Honda VFR750
1985 Honda VF750
1982 Kawasaki 750GPZ
1975 Norton 850 Commando
    

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