BMW K bikes (Bricks)

You are not connected. Please login or register

View previous topic View next topic Go down  Message [Page 1 of 1]


1Back to top Go down   1985 K100 Empty 1985 K100 on Sun Aug 02, 2015 12:58 pm

jkom67

jkom67
active member
active member
Hello K100 owners, enthusiasts, and Gurus...

Hoping for some tips on my front forks. They were feeling hoppy especially in higher speed corners which is a little disconcerting at the least! No damping, thus no rebound. I decided to change the oil. I started by placing it on the center stand and elevating the front wheel, I drained the fairly clean oil by removing the 10mm bolt at the bottom and then the allen bolt from the top. I re-filled with Spectro 5W fork oil to 360cc. No difference at all, the fork is actually resting at bottom, I have to pull up to get any action?

Please help!

Jason

http://www.Retro-Rides.ca
    

2Back to top Go down   1985 K100 Empty Re: 1985 K100 on Sun Aug 02, 2015 1:41 pm

Comberjohn

Comberjohn
Life time member
Life time member
Hi Jason.
I would have said that 5w is a bit on the light side and would use 10w.
K100's are notoriously fussy about how much oil goes in each fork leg, too. Last one I had was seriously firm and uncomfortable to use on bumpy roads. Too much oil.
Replaced it with 365cc(?) Of 10w and it was great.
The other thing to check is to see if they are the original forks. As yours is an '85 they may have been changed at some point and there are a few different types.
You'll find a number cast on the side towards the wheel of the alloy sliders that can help to identify them.
Only other thing is if it has big miles, many do, it may be time to change to a pair of progressive springs.
Do a search on the forum about forks. It's a bit like opinions on tyres, plenty of information.


__________________________________________________
Life is not a rehearsal.
2010 VFR 1200F DCT 
2010 R1200GS(gone)
1986 K100 Silver(gone)
2012 K1600GT(gone)
1984 K100RT Madison Silver(gone)
1989 K100LT Stratus Grey(gone)
1984 K100 Red(gone)
http://www.johnsdrivingschool.co
    

3Back to top Go down   1985 K100 Empty Re: 1985 K100 on Sun Aug 02, 2015 2:28 pm

nino

avatar
Life time member
Life time member
Hi Jason, new oil wouldnt change problematic handling of old K specially in curves.I agree with Comberjohn and  reccomend to think about progressive springs for your old forks. I changed old tired springs in 83 forks with Wurth progressive springs an fill with 400 ml of 7,5 w oil. It changed a bike handling totally.
Best regards

    

4Back to top Go down   1985 K100 Empty Re: 1985 K100 on Sun Aug 02, 2015 8:26 pm

RicK G

RicK G
admin
admin
Sounds to me like the springs are sagging a lot and by the picture you posted they are sagging.


__________________________________________________
"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
    

5Back to top Go down   1985 K100 Empty Re: 1985 K100 on Sun Aug 02, 2015 9:01 pm

jkom67

jkom67
active member
active member
Thanks gents... Time to pull it apart. I am in Canada and just did an extensive Google search for new springs. I could not find any! Any suggestions for sourcing?


 Anyone familiar with the alloy pieces under the plastic cap with the oil fill allen bolt? You need to hold them with a wrench in order to loosen and tighten the allen bolt. why is it made to turn? is it some kind of preload adjuster?

http://www.Retro-Rides.ca
    

6Back to top Go down   1985 K100 Empty Re: 1985 K100 on Sun Aug 02, 2015 9:42 pm

RicK G

RicK G
admin
admin
That is a bung with an O-ring and is free floating, held in with a wire circlip.  You push it down and get a fine point and pick the clip out then the spring comes out. If you remove the handlebars the spring will lift out easily.

"Progressive" brand springs are of reasonable quality and price, most bike shops would be able to order some in.


__________________________________________________
"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
    

7Back to top Go down   1985 K100 Empty Re: 1985 K100 on Tue Aug 04, 2015 10:50 am

jkom67

jkom67
active member
active member
Thanks Rick G

http://www.Retro-Rides.ca
    

8Back to top Go down   1985 K100 Empty Re: 1985 K100 on Tue Aug 04, 2015 9:46 pm

JR_K100RS

JR_K100RS
Life time member
Life time member
G'day jkom67 , just reading your original technique to change the fork oil , you said you removed a 10mm bolt at the bottom to drain the oil , I'm no sure that this is the correct process , the drain hole is at the back of the fork leg and is only a 5mm socket head cap screw , happy to be corrected by other wiser heads

John R


__________________________________________________
Diamond Grey ( 617 ) 1987 K100RS ( European Delivery ) Original owner
    

9Back to top Go down   1985 K100 Empty Re: 1985 K100 on Tue Aug 04, 2015 10:18 pm

jkom67

jkom67
active member
active member
Hi John R,

On mine it is in fact a bolt with 10mm head, bottom back of forks!

http://www.Retro-Rides.ca
    

10Back to top Go down   1985 K100 Empty Re: 1985 K100 on Tue Aug 04, 2015 10:41 pm

duck

duck
Life time member
Life time member
If I were you I'd look into swapping in some newer K75 or K100 forks from Fleabay or wherever. The early K 100's did not have a fork brace which some of the later K100 models and all K75s had. (There used to be an aftermarket fork brace called Telefix or something like that but those are long out of production.)

I recently redid an 86 K100RS and swapped in some K75 forks with a fork brace.

As for fork oil, I have always had good luck with Honda SS-8 (which is a 10W oil.)


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
98 Taxi Cab K1200RS
14 K1600GT
http://www.ClassicKBikes.com
    

11Back to top Go down   1985 K100 Empty Re: 1985 K100 on Wed Aug 05, 2015 12:08 am

jkom67

jkom67
active member
active member
Thanks duck... Will put that into the realm of possibilities! 

Any advice on exhaust mods?? Curious!

http://www.Retro-Rides.ca
    

12Back to top Go down   1985 K100 Empty Re: 1985 K100 on Wed Aug 05, 2015 2:08 am

JR_K100RS

JR_K100RS
Life time member
Life time member
@jkom67 wrote:Hi John R,

On mine it is in fact a bolt with 10mm head, bottom back of forks!

well ok then , yup the head is 10mm in diameter , just making sure you are not undoing something that you shouldn't

John R


__________________________________________________
Diamond Grey ( 617 ) 1987 K100RS ( European Delivery ) Original owner
    

13Back to top Go down   1985 K100 Empty Re: 1985 K100 on Wed Aug 05, 2015 2:40 am

duck

duck
Life time member
Life time member
@jkom67 wrote:Thanks duck... Will put that into the realm of possibilities! 

Any advice on exhaust mods?? Curious!

Exhaust? Oh my, what a can of worms.

1 - If you bought a 600# bike designed 30+ years ago and your primary concern is performance then you should've just bought a newer 600RR, liter bike or Busa.

2 - If what you want is a loud "look at me" bike then you should've bought a cruiser and removed the baffles. 

3 - If you want to know what's available for an 85 K100 and want my (admittedly biased) opinion then there I can help. I've run several different exhausts on K100s so I have some experience there. Too much to type though.

I only have free long distance in the US but I'd be happy to spend some time BSing with you if you want to call me.  Just drop me a PM asking for my phone number.


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
98 Taxi Cab K1200RS
14 K1600GT
http://www.ClassicKBikes.com
    

14Back to top Go down   1985 K100 Empty Re: 1985 K100 on Wed Aug 12, 2015 11:26 am

jkom67

jkom67
active member
active member
Well, new Progressive springs with spacers sized at 2.5" are in with 50/50 5 and 10 weight Spectro oil. The fork still sits at bottom! I pull up and hear a whooshing sound, push down, same sound, she just sits, does not spring back at all. I have rebuilt forks from the 60's to the 2000's never encountered this... 

Any ideas gents?

http://www.Retro-Rides.ca
    

15Back to top Go down   1985 K100 Empty Re: 1985 K100 on Wed Aug 12, 2015 2:18 pm

Dai

Dai
Life time member
Life time member
Missing spacer? Which forks do you have?


__________________________________________________
1983 K100 upgraded to K100RS spec, 1987 K100RT
Others...
1978 Moto Guzzi 850-T3, 1979 Moto Guzzi 850-T3 California,1993 Moto Guzzi 1100ie California
2020 Royal Enfield Bullet 500
    

16Back to top Go down   1985 K100 Empty Re: 1985 K100 on Wed Aug 12, 2015 8:14 pm

RicK G

RicK G
admin
admin
When you lift the front up is there any load on the top bung or can you push it down and it stays there.


__________________________________________________
"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
    

17Back to top Go down   1985 K100 Empty Re: 1985 K100 on Mon Aug 17, 2015 1:15 pm

jkom67

jkom67
active member
active member
@RicK G wrote:When you lift the front up is there any load on the top bung or can you push it down and it stays there.
There is load, after I installed the new progressive spring and spacers I had to ask someone else to hold the bung down while I installed the clips. It took a lot of effort! When I jack up the front of the K after it has been sitting the lowers/wheel visibly drop several inches.

http://www.Retro-Rides.ca
    

18Back to top Go down   1985 K100 Empty Re: 1985 K100 on Mon Aug 17, 2015 8:23 pm

RicK G

RicK G
admin
admin
Some more questions, do the fork legs slide freely when there is no spring in them and just by themselves, no wheel and no fender?  Are the legs parallel, it is possible the tripple clamps are twisted and that can prevent the fork sliding or make it stick in one place mainly when when all is bolted up tight.
Undo the bolts at the bottom of the fork that clamp the axle 2 on each side also release the bolt in the end of the axle and bounce the front end a few times. This allows the forks to find the right place on the axle and makes sure they slide freely (not to be confused with a twisted clamp) then tighten all the bolts and see if there is an improvement.


__________________________________________________
"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
    

19Back to top Go down   1985 K100 Empty Re: 1985 K100 on Tue Aug 18, 2015 11:23 am

jkom67

jkom67
active member
active member
@RicK G wrote:Some more questions, do the fork legs slide freely when there is no spring in them and just by themselves, no wheel and no fender?  Are the legs parallel, it is possible the tripple clamps are twisted and that can prevent the fork sliding or make it stick in one place mainly when when all is bolted up tight.
Undo the bolts at the bottom of the fork that clamp the axle 2 on each side also release the bolt in the end of the axle and bounce the front end a few times. This allows the forks to find the right place on the axle and makes sure they slide freely (not to be confused with a twisted clamp) then tighten all the bolts and see if there is an improvement.
Rick G! Huge improvement with the above described!! 

You my friend are officially a guru in my estimation...!

Oh lord it feels so good to have buttery smooth front suspension!

Much thanks to you!Very Happy

http://www.Retro-Rides.ca
    

20Back to top Go down   1985 K100 Empty Re: 1985 K100 on Tue Aug 18, 2015 9:19 pm

RicK G

RicK G
admin
admin
:BW:


__________________________________________________
"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
    

View previous topic View next topic Back to top  Message [Page 1 of 1]

Permissions in this forum:
You cannot reply to topics in this forum