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post #1 of 7 (permalink) Old 07-30-2009, 08:21 PM Thread Starter
 
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fork question

hey guys, where do i look to see if my fork seals are leaking?
also, feels like they're bottoming out under hard braking. i have an '03 with 7400 miles on it. sometimes with quick stops i can feel it hitting the wall, ya know what i mean?
thanks.
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post #2 of 7 (permalink) Old 07-31-2009, 08:00 AM
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There will be fork fluid on the calipers and on the bottom of the forks!
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post #3 of 7 (permalink) Old 07-31-2009, 09:26 PM Thread Starter
 
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hmmmm. calipers are dry...there is a slight film as far as the forks compress though.
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post #4 of 7 (permalink) Old 07-31-2009, 10:11 PM
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How's your front preload? Is it insufficient so your ride height is too low and then bottoms out under braking?
Or, how is your compression damping? Does your front end dive too quickly under braking, then bottoms out?
Have your fork been worked on recently?
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post #5 of 7 (permalink) Old 08-02-2009, 11:49 AM Thread Starter
 
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no, no fork work done.
diving too quickly under braking and bottoming out is exactly what it's doing.

i will admit i know next to nothing about suspension settings. i did mess with the settings a little last year though. i weigh 215 lbs and only ride in the street. any suggestions sub?

Last edited by TMFD; 08-02-2009 at 11:52 AM.
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post #6 of 7 (permalink) Old 08-02-2009, 02:24 PM
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Well if you have oily residue on one or more fork leg, then you've got a leaky fork seal.
How much and how long is the next question.
Your forks should never physically bottom out except under extreme situations.

You'll need to fix the leaks by replacing the seals.
When they fix the seals, they will add fork oil.
For oil, the usual is a 7 weight fork oil for cartridge forks.
The amount is 428cc per the service manual or 120mm of measure oil height as a baseline.

How many turns out from full in are your fork preload adjusters set?
If you don't know, take a piece of tape and stick it on a 22mm socket and a matching piece of tape on the fork cap to create an index mark.
The gently rotate the adjuster clockwise until it gently stops.
All the while counting the number or fractions of turns, then jot them down for each leg.

Next you can find two small zip ties and zip them around one fork leg snug enough to stay in place.
Then raise up to the top of the dust seal. The using a friend, gently mount the bike have your buddy hold the bike vertical while you assume a normal riding posture.
Hold that position for a few moments, then gently dismount.
Then measure the distance from the top of the zip tie down to the end of the fork slider where the fork bottom begins.
Subtract this number from 119-120mm which is the stock SP2 fork fully extended length.
If you're getting numbers greater than 40mm, then you may need to apply more preload.
You can try for 36-38mm as a baseline for starters.

Also, what is your fork compression adjuster settings?
The high velocity or bump compression is a function of oil viscosity and valving.
The lower velocity or weight transfer compression is adjusted using the compression adjuster knobs on the forks.

If your bike is diving too quickly, the try increasing the compression adjuster two clicks and see the result. If getting close, then change by one click either way until ok.

The stock fork springs are 1 Kg/mm and the rate for your weight is .93 Kg/mm.
In the future you might replace the springs with the correct rate.
They usually cost about $100 for a set.

Last edited by SubSailor; 08-02-2009 at 02:28 PM.
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post #7 of 7 (permalink) Old 08-03-2009, 08:33 PM Thread Starter
 
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thanks sub. you are fountain of knowledge, my friend.
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