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1Back to top Go down   Strange brake behavior? Empty Strange brake behavior? Wed Apr 24, 2013 3:58 am

Rabidchiwawa007

Rabidchiwawa007
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This is in regards to a 1992 16v k100rs.

This is most noticeable while on a hill, thanks to gravity. Anyways, while stopped at idle, with the front brake applied, if I rev the bike mildly quickly up to around 3k, the brake lever will actually push itself out and stick there for a second before actually allowing me to pull it back in. The brakes release and everything. It's very odd. The same thing happens when I have the rear brake applied. The brake pedal will essentially push itself back up, release the brake, and stick there for a second before allowing me to push it back down.

If I rev it *slowly* up all the way to 7k-ish, the brakes remain unaffected.

I feel that this could be related to the ABS, but that is functioning normally as far as I can tell.

Any ideas?


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1968 BSA Lightning
1991 BMW K100RS 16v with K1100LT fairing
    

2Back to top Go down   Strange brake behavior? Empty Re: Strange brake behavior? Wed Apr 24, 2013 4:52 am

92KK 84WW Olaf

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I cant say for certain about he K but I had the same behaviour on a 2000 Mercedes E Class which did have ABS and Brake Assist.

But the K does not have a servo the way a car does so it may not be the same. Does everything else behave normally?

92KK



Last edited by 92KK K100LT 193214 on Thu Apr 25, 2013 4:27 am; edited 1 time in total (Reason for editing : Typos.)


__________________________________________________
1992 K100LT 0193214 Bertha Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red 578 bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 689 58,645 now 106,950 miles Deceased.
1983 K100RS 0011171 Fricka 606 Alaska Blue 29,495 miles Damn K Pox Its a Bat outta Hell Now 37,190 miles. 
1996 K1100LT 0233004 Lohengrin Mystic Red 38,000 miles currently 42,640 miles.

Past:
1968 Yamaha 80 YG1
1971 Yamaha 125 YAS-1
1968 Honda 125 SS
1970 Honda CD 175
1973 Honda CB500-4
Honda CX 500
    

3Back to top Go down   Strange brake behavior? Empty Re: Strange brake behavior? Wed Apr 24, 2013 4:58 am

Rabidchiwawa007

Rabidchiwawa007
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Yep, everything else on the bike behaves normally (finally!)


__________________________________________________
1968 BSA Lightning
1991 BMW K100RS 16v with K1100LT fairing
    

4Back to top Go down   Strange brake behavior? Empty Re: Strange brake behavior? Wed Apr 24, 2013 6:20 am

Basic2

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I'm guessing the rapid change in battery voltage from idle is affecting the ABS brake modulators.


__________________________________________________
K100 Basic 2
11/1987 6308319K100CJ
Marakesh Red
    

5Back to top Go down   Strange brake behavior? Empty Re: Strange brake behavior? Wed Apr 24, 2013 7:19 am

RicK G

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@Basic2 wrote:I'm guessing the rapid change in battery voltage from idle is affecting the ABS brake modulators.

This would be the only thing I could come up with, maybe an email to Tosi Tabuki the ABS genius in Japan, he may be able to shed some light on it. Like you say it sure is a strange one, maybe its possesed and I don't mean by a finance company. Twisted Evil


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

6Back to top Go down   Strange brake behavior? Empty Re: Strange brake behavior? Wed Apr 24, 2013 1:13 pm

92KK 84WW Olaf

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Funny now that you mention battery voltage I recall this was much less noticeable after I replaced the battery.......

Some other issues arose and the suggestion was to run a diagnostic check at €75 plus VAT but that it was likely to be the battery. I spent the money on a battery instead.


__________________________________________________
1992 K100LT 0193214 Bertha Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red 578 bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 689 58,645 now 106,950 miles Deceased.
1983 K100RS 0011171 Fricka 606 Alaska Blue 29,495 miles Damn K Pox Its a Bat outta Hell Now 37,190 miles. 
1996 K1100LT 0233004 Lohengrin Mystic Red 38,000 miles currently 42,640 miles.

Past:
1968 Yamaha 80 YG1
1971 Yamaha 125 YAS-1
1968 Honda 125 SS
1970 Honda CD 175
1973 Honda CB500-4
Honda CX 500
    

7Back to top Go down   Strange brake behavior? Empty Re: Strange brake behavior? Wed Apr 24, 2013 2:14 pm

Rabidchiwawa007

Rabidchiwawa007
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Battery is brand new too! Razz.

Well, if / when I figure this out, I'll post back and let you all know.


__________________________________________________
1968 BSA Lightning
1991 BMW K100RS 16v with K1100LT fairing
    

8Back to top Go down   Strange brake behavior? Empty Re: Strange brake behavior? Wed May 08, 2013 4:26 am

K-BIKE

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That is an interesting phenomenon I guess the first questions that form in my mind are have all connections to and from the ABS been treated with DeoxIT to rule out any odd connection issues. Next what is the battery voltage at idle and how does that rise when you open the throttle so as to eliminate any weird voltage fluctuations from the diagnosis. If the alternator/regulator electronics/regulator brushes/slip rings have a problem you could be getting strange voltages out. Use an accurate fast DVM to do the check.

I would read out any fault codes stored as well just to see if anything is stored there once you have done that do a CPU reset and see if the problem is still there and read the fault codes again.

Last quick check after all the above is get a friend to swap their ABS CPU into your bike does the problem go away? If it does that would indicate to me that the problem is CPU related having already eliminated all connection and voltage issues.

Let us know what you find.

Regards,
K-BIKE

    

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