front forks bottoming out on hard braking

[racinrich]

replaced the front fork seals 2 months ago, easiest rebuild ever , replaced top bushing in body of shock , no extra parts no metal in tubes, leaks gone used 10 w like I used last year, now on hard braking front end is banging ,its not abs activation, any ideas

[johnny]

im calling insufficient suspension fluid...

id drain it and refill it... 300ml left 350ml right...

http://www.ibmwr.org/ktech/fork-oil.shtml

j o

[Scott_]

I'm going to suggest weak springs, especially if they are still the 20+ year old originals.

[Inge K.]

im calling insufficient suspension fluid...

id drain it and refill it... 300ml left 350ml right...

j o

Yes, Johnny you're correct about the suggested amount being insufficient...............should be 350/400 ml L/R.

[johnny]

no wonder my forks are whack... im 50ml short on both...

j o

[jacksdad1963]

Try wrapping a cable (zip?) tie around a fork leg, then you can see how far the front end is diving: if the tie is pushed up to towards the lower yoke then I'd suggest thicker oil.
One thing I've been told, the viscosity of fork oil differs from maker to maker :mbird
I've used Rock Oil 15W, yet my cable tie is still going towards the end of the 'normal' travel, so I'm going to try a different make but still 15's grade :2thumbup:

[TimTyler]

I thought that fork oil had more to do with rebound dampening (stretching out) than on compression dampening.

After I rebuilt my forks this summer I sometimes hear knocking on the rebound. The only part I replaced was the piston Guide Ring (31 42 1450517).

[roninvt]

I believe on a k1100 the right fork handles rebound damping and the left is for compression.  I would drain them to check the volume.  If the volume is correct, you could try a heavier oil, but 15 sound pretty thick to me.  I am using Belray 10w in mine and they are plenty stiff, maybe too much. 

[johnny]

can always cut a couple 13mm pieces of pvc plumbing pipe and stick them in the tubes at the top of the springs...

j o

[racinrich]

fluid level makes sense .put same amount in both on rebuild, and last year only drain and filled left. rt was resealed by another hack.whe all else fails read the instructions.

[pdg]

can always cut a couple 13mm pieces of pvc plumbing pipe and stick them in the tubes at the top of the springs...

j o

I used some rubber bungs to give a bit of elastic preload to my progressive fork springs ;)