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post #1 of 21 (permalink) Old 12-29-2012, 04:43 PM Thread Starter
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fork question

Hey guys just a quick question. I have lowered several bikes. and have never had this issues before.. 1st on the Kawi though..

Bike:
02 zx6r
19K miles
9" extension
lowered 1" in front and rear

Issue:
almost every bump the front fender hits the upper faring, it seems like the front springs are really loose, I turned the spring rate to hard, but its still doing it.. Is there something wrong with the forks??
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post #2 of 21 (permalink) Old 12-29-2012, 06:12 PM
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The spring rate doesn't change. "Turning the spring rate to hard" just compresses them more and causes the bike it "sit lower" at rest. You need to increase the compression damping not the preload on the forks.

That swingarm extension won't help either as it likely dropped the bike even more.

Personally, I would see what happens when you set the bike back to stock height and then set the preload correctly.

Of course I'm generalizing from a single example here, but everyone does that. At least I do.


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post #3 of 21 (permalink) Old 12-29-2012, 06:36 PM Thread Starter
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Correct me If i am wrong. but the spring rate adjustment is the flat head screw at the top of the forks?

" increase the compression damping" please explain.. how?


As for the swingarm, It is just the opposite. When you extend the rear it lifts the bike.. I lowered it 1" which is back to stock height
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post #4 of 21 (permalink) Old 12-29-2012, 06:59 PM
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You cannot adjust a spring rate without replacing the spring. Spring rate is a measurement of how much force it takes to compress the spring. For example:

If you had a 1lb/inch spring one lb of pressure would compress the spring 1 inch. If you put two lbs of pressure on it you would compress it by 2 inches. If you tighten down the preload (squish the spring an inch) then put one lb of pressure on the spring you only squish it one inch. Basically, the spring rate stays the same.

I don't have access to a set of your forks so I cannot tell you what adjustments are on them off the top of my head. But, look at it this way.

You have three adjustments on most forks:

Preload - how much the spring is squished
Compression damping - speed at which the fork squishes
Rebound damping - speed at which fork returns to normal resting point

IF you dropped the front, then cranked down the preload then you have effectively dropped the front of the bike as low as possible.

IF memory serves the flathead adjustment on the top (again going from memory) is actually rebound damping meaning that with it cranked in all the way you're actually forcing the fork to remain in its compressed position for as long as possible (it will take the longest amount of time to fully extend after a bump).

Of course I'm generalizing from a single example here, but everyone does that. At least I do.


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post #5 of 21 (permalink) Old 12-29-2012, 07:23 PM Thread Starter
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If I turn the screw back out "soft" than it should raise the front some, some maybe it would help?? I planned to raise the front back up 1/4"-1/2" tomorrow. just trying to figure this out.. Never had this problem on any of the Gsxr's i have done..
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post #6 of 21 (permalink) Old 12-29-2012, 07:35 PM
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Quote:
Originally Posted by Sharkyreef View Post
If I turn the screw back out "soft" than it should raise the front some, some maybe it would help?? I planned to raise the front back up 1/4"-1/2" tomorrow. just trying to figure this out.. Never had this problem on any of the Gsxr's i have done..

I feel like making a joke about squids and GSXR's... but that's too easy.

Suffice to say that if you don't understand what something does, you shouldn't be fucking with it. I think the issue that you're having trouble with is that you don't understand what the adjusters you're spinning do. And rather then do the research to find out how to do it correctly you just started spinning things. You pretty much dropped yourself into this without a real clue (was that too bitchy HassieM?). And to make matters worse you're still assuming that what you were turning has anything to do with the spring rate. Compression and rebound adjustment control how quickly the oil moves through the damping holes adjusting how fast the fork compresses and extends. Turning it back to "soft" likely means that the fork will extend faster, not that it will raise the height.

Also, rebound needs to be set front and rear... it needs to be adjusted after a the suspension is warm to set it so that the bike maintains a neutral posture and follows the road smoothly. Rebound and compression are for keeping the wheel following the road smoothly. Preload is for setting where in the stroke the bike sits at rest. What I'm getting at is that quite simply "turning it back" to where you were isn't even setting that correctly.

That being said, it is possible that you now have the wrong spring rate in there, but removing 1" of travel from that bike and expecting it to behave normally is a mistake.

Of course I'm generalizing from a single example here, but everyone does that. At least I do.


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post #7 of 21 (permalink) Old 12-29-2012, 11:36 PM Thread Starter
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This bike was in box's when i bought it.. as in Frame sitting on the ground.. Wasn't even a roller.. I am not a Newbie rider nor builder, When it comes to the shocks. I had a race shop adjust them for me... I am just looking for a simple hand, or a few things to try. I test ride every adjustment i make..
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post #8 of 21 (permalink) Old 12-30-2012, 01:14 AM
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Adjustments that you don't understand aren't ones you should be making.

Of course I'm generalizing from a single example here, but everyone does that. At least I do.


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post #9 of 21 (permalink) Old 12-30-2012, 09:30 AM Thread Starter
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Hents why im asking questions..
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post #10 of 21 (permalink) Old 12-30-2012, 11:58 AM
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After you messed things up...

Of course I'm generalizing from a single example here, but everyone does that. At least I do.


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