Rear end kick

merlinnn

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Nov 30, 2002
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#1
Hi there,

Last weekend I was riding a new track that was more open and hi-speed then my local. I was coming down a straight section in 4th gear at about quarter to half throttle, standing and gripping the bike with my knee's when all of a sudden BANG both feet were lifted of the pegs and I was virtually thrown over the bars. This only happened once, and I was curious as to what would reduce/prevent this from happening again. More comp or rebound?
 
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#2
My vote is more comp. It went tru the stroke too fast causing a bottoming when you didn't expect it. Took you of guard. It was a high speed blow. So search for the h-s clicker
 
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#3
Maybe duct tape the feet to the pegs ??
My bike doesn't do this[kick], but several times per ride the rear end will deflect violently sideways off of a rock and end up 3 feet out to one side. Anyone know the correct terminology for this annoying manouver or better yet how to eliminate it ?
 
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#4
Slow down the rebound by making it stiffer had this problem with my 250F till I did that. Since your are going at higher speeds I would suggest backing off the comp a few clicks, sounds like to me you rebounded too fast. Just play with the adjustment and if you make a change and don't like it you can always go back.
 

kevin5758

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#5
This is one of those things that can be caused by different and opposite settings.
If this happened when you were at the middle or end of a rough section I would guess the rebound is to slow. It packed up and then ran out of travel and kicked. This would be exagerated by compression / sag to soft which allows it to compress to far into the compression stroke, coupled with the slow rebound, causing it to run out of available travel. IMO, a couple clicks on the compression adjuster will have little to no noticable effect on a kick of this magnitude. Check what the normal rebound range is (owners manual) and see where your adjuster is set in comparison.

http://www.shimprogram.com/test_riders_handbook_1.htm
 
Last edited:

merlinnn

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#6
Thanks for your advice everyone, I am running about 15 clicks out on comp, the high speed is standard. Rebound is at 10. The bike is 03 YZ 250. The only thing different from standards is heavier springs .44 up front and 5.4 rear. Standard is .43 and 4.9. Too little compression, combined with to much rebound? I will have to wait till the 28th to ride that track again.
 
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#7
Hi, got your shock replaced i assume.
On the stock shock try this, 100mm race sag, low speed 12 out, high speed full soft, rebound 10 out . I would like to show you just how good your shock can be made to work, if you let me revalve it for you. Check out my website and give me a call.