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1Back to top Go down    Front suspension on Mon 1 Oct - 20:50

BillOwens

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Just had our club inspector pass bike for classic rego
He felt the front suspension seemed soft, ie it would dive under front braking
Can it be stiffened, it certainly is softer than the Ducati

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2Back to top Go down    Re: Front suspension on Mon 1 Oct - 21:28

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Hello Bill,
If you do a search you'll find plenty of discussion on this topic.
Yes, the front suspension is a bit soft or perhaps better known as compliant.
First thing to do is change the fork oil. It may have been in there since Moses played fullback for Jerusalem.
Then work from there...progressive springs etc.
It's a good idea to put your bike model and year in your signature.

Sean.

    

3Back to top Go down    Re: Front suspension on Mon 1 Oct - 21:38

RicK G

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They are very touchy on the grade of oil some use 5SAE and 7.5 or 10 and some even mix grades to their liking but anything over 10 weight usually rattles the bones a bit.


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"Every normal man must be tempted, at times, to spit upon his hands, hoist the black flag, and begin slitting throats." from Mencken's 1919 Prejudices

Bikes 1993 K1100 LT, 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 for now
    

4Back to top Go down    Re: Front suspension on Mon 1 Oct - 21:47

88

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+1 what the guys say Bill.

When I got my LT the fork dive was waaay to much for my liking. I replaced the fork oil with 10w (IIRC) and the difference meant that I could put all thoughts of spring replacement aside.

Here's a recent thread on the subject with some handy tips.


88


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88....May contain nuts!

"The world is a book and those who do not travel read only one page." - St. Augustine from 1600 years ago & still true!

Bike: K100LT 1988. 0172363. AKA the Bullion Brick! Mods: k1100 screen and stands.
K1: 1990. 6374189. Custom Stealth Black paint.
    

5Back to top Go down    Re: Front suspension on Tue 2 Oct - 1:03

Two Wheels Better

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I've retrofitted the K75S 'S' front forks to my K100RS. The difference in feel (and reduced suspension travel) is amazing; they are much firmer than the typical long travel front suspension. The 'S' forks use only 280cc of fork oil and the weight I decided upon after trying all weights is 5W. I weigh less than 85kg dressed for the sunshine in a sudden downpour.

Using 10 or 15W oil can help but often it's a matter of not enough fluid in the forks in the first place. I recommend a flush and refill with the correct level spec to see how much it changes. Barring that, some Progressive springs or replacement with the OEM might make a difference.


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Bricks: '87 K100RS & Big Block'93 K11 frame, forks, Paralever & gearbox w/'02 K1200RS motor, brakes & wheels.
Other: '09 K1300GT, '07 K1200R, '04 R1150RT, '95 R100 Mystic & '77 R75/7-R100 dual-plugged w/340 cam, big valves, 40mm carbs & exhaust.
    

6Back to top Go down    Front suspension on Wed 3 Oct - 19:27

BillOwens

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Will do a drain and refill this weekend, is 360 ml per fork correct
Is there an easy way of getting the new oil in?
Should I use my compressor to blow all the old stuff out?


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1984 BMW K100 RS black,90,000km, 1982 Ducati Pantah 600SL 2,000km since restoration, 1949 Velocette Mac 350, undergoing restoration
http://www.wdmoc.com
    

7Back to top Go down    Re: Front suspension on Wed 3 Oct - 20:10

RicK G

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Use a bit of aluminium foil to keep the oil away from the discs and remove the top bung then the bottom bung as there is often pressure in there. You will need a gas mask , it will stink.
I use a big 100ml syringe to put the oil in the top and measure it, got it from a vet.


__________________________________________________
"Every normal man must be tempted, at times, to spit upon his hands, hoist the black flag, and begin slitting throats." from Mencken's 1919 Prejudices

Bikes 1993 K1100 LT, 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 for now
    

8Back to top Go down    Re: Front suspension on Wed 3 Oct - 20:10

rosskko

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Not sure about the compressor, but use a horse syringe. Takes a few to get it all in, but you won't spill any.
I tried a pvc hose and funnel. If you have a really small diameter hose it is ok, but the air obviously needs to get out.


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1986 K100RT VIN 0093801K100RT with summer fairing for a northern visitor

Basic/2 6308802K100CJ05/1988

K1100RS 0194321
    

9Back to top Go down    Re: Front suspension on Wed 3 Oct - 21:49

charlie99

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bill there is usually enough suction to work the oil out the bleeder holes at the bottom with a few pumps of the front end on the handle bars .

our good friend inge posted a fantastcic tool for keeping the oil from blowing all over the forks disks et all ... durring the empty process

its a cut up bottle ...hope i can find the pic again (might have to use the search feature )


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

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

10Back to top Go down    Re: Front suspension on Wed 3 Oct - 22:00

Inge K.

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It was in a thread where RT was changing his fork oil.
And did find one of the drain holes clogged,...or was the leg empty......?





Last edited by Inge K. on Wed 3 Oct - 22:06; edited 1 time in total (Reason for editing : Adding pictures.)


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Inge K.
K100RS -86. (first owner), K1100LTSE -94.
    

11Back to top Go down    Re: Front suspension on Wed 3 Oct - 22:10

rosskko

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1986 K100RT VIN 0093801K100RT with summer fairing for a northern visitor

Basic/2 6308802K100CJ05/1988

K1100RS 0194321
    

12Back to top Go down    Re: Front suspension on Thu 4 Oct - 1:57

Motorandy123

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I recently installed some K100 springs that I cut down by 2" to get the appropriate
stiffness. According to Racetech the stockers are 0.72 kg/mm and 0.80 to 0.85 would
be best. I threw in some lightly thicker oil (10 w) to bring the rebound back and she
should be all set!

    

13Back to top Go down    Fork oil change on Sun 7 Oct - 21:14

BillOwens

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Drained both forks, still oil but watery and probably 200ml per side
Put 360ml sae10 per side. No leaks yet, rides well
Also got 2 nd hand mount for the broken one that came with it


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1984 BMW K100 RS black,90,000km, 1982 Ducati Pantah 600SL 2,000km since restoration, 1949 Velocette Mac 350, undergoing restoration
http://www.wdmoc.com
    

14Back to top Go down    Re: Front suspension on Sun 7 Oct - 21:35

charlie99

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good work bill ...amazing what fresh oil does for the ride

happy times ol mate !


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

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

15Back to top Go down    Re: Front suspension on Sun 7 Oct - 22:49

RicK G

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Bill if your seals have been leaking (I am not sure if they were) check the radiator as the oil gets there and collects dust and clogs the fins on the outside.


__________________________________________________
"Every normal man must be tempted, at times, to spit upon his hands, hoist the black flag, and begin slitting throats." from Mencken's 1919 Prejudices

Bikes 1993 K1100 LT, 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki X 2 for now
    

16Back to top Go down    Re: Front suspension on Sun 7 Oct - 22:59

Inge K.

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Good advice,......as always.


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Inge K.
K100RS -86. (first owner), K1100LTSE -94.
    

17Back to top Go down    Front forks on Mon 8 Oct - 19:14

BillOwens

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Thanks for the advice Rick, will check asap


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1984 BMW K100 RS black,90,000km, 1982 Ducati Pantah 600SL 2,000km since restoration, 1949 Velocette Mac 350, undergoing restoration
http://www.wdmoc.com
    

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