New suspension lead to swapping?

[jmdsurf45]

New to the forum so don't beat me up! I just had my son's suspension done on his new 06 KX85 and he rode it for the first time this past weekend at one of our local tracks, 3 Palms. He said that the bike was running and handling well untill he was going down this long bumpy straight away, which he had gone down several times, wide open when the front end began to shake and the bike started swapping and he went down really hard seriously injuring him and messing up the bike pretty bad. My question is, could the new suspension job of caused the incident or was it just from lack of knowledge or experience on my sons part. He is ready to ride again and wouldn't want to have to go through that again. Thanks for any suggestions or comments.

[Silver_Fox]

Incorrect suspension setting would certainly cause headshake. There are a number of factors that contribute to headshake, damping adjustments fork and shock, fork height, and even tire pressure.

Hope he is ok, there is nothing more frightfull than trying to hang on to a bike that wants to swap ends, oooooh those memories of the bars getting ripped out of my hands and breaking my collarbone are coming back.

[MXtras]

How is the front to back suspension balance? Sounds like maybe the front is much softer than the back.

Are the forks mounted high in the clamps? Dropping the forks down a bit may help a little but it might cost him a little in the corners.

I am new here also by the way so you are not alone!



Scott

[schwen_108]

Sounds like the rear end was squatting a little too much going down the hill, causing the front end to ride up just enough to get headshake.
I say, get get it redone. perhaps just set up for him. Take it to someone who knows what they're doing with suspension, have HIM tell them whats' what with it and they should know how to fix it. I did that after my first ride on my CR, took it to one of the local suspension companys (no longer in business anymore ) The guy knew exactly what was wrong and set it up for me. The next day I went riding with it and it was perfect.

[Big Maico 393]

Which track was he on? if it was the river track, it was most likely the wet sand caught the front end & took him for a ride, I almost did the same thing on the 525, but I had the HP to pull it out & recover.

I didn't ride the main track Saturday, but it did look to have a few spots in it that might be a little soft & gooey

[jmdsurf45]

We, Ben, JoeJoe, my son and I were putting in some real fast lap times on the GP track, RIGHT!, when I got off the track near the entrance under the tree at the left turn. Matthew passed both of them in that flat left turn before the small whoop section. He said he was pinned after that small step down table when his front end stared shaking bad, he said he let go and shut his eyes. From a distance I saw the green bike going end over end and then saw a blue bike flip, JoeJoe,s, and went down. I ran across that track as fast as I could run, alot of people had already stopped to help. Matthew seemed Ok but was crying and after seeing his bike even cryed more. JoeJoe was pretty beat up also. Anyway the bike was handling great all day, I think he just got tired and forgot to grip the bike through that section. Your right the tracks were pretty boggy early, I had a hard time on my 250. Anyway, you have any suggestions on what we can work on to prevent this from happening again since your the all wise one. Thanks

[Big Maico 393]

Mathew will have to learn that the throttle can be your friend or your worst enemy. he will learn when to gas it & hold on & when to roll off you never shut the throttle unless you want to take a huge dirt sample!

I wasn't there to see what happened, so I can only guess that he might have backed off the throttle or been in the wrong position on the bike,causing the front end to get heavy & shake. it also has todo with timing of the woops or braking bumps. it's a learned art & it will take time.

You said that the bike was handling well up to that point? so it could be the suspension, but without seeing it I couldn't tell you.

[MXtras]

Big Maico mentions body position - good point. When entering a rough section (whoops, breaking bumps, deep sand, etc) you want to attack it with your body towards the back of the bike and your arms straight - this will allow you to control a slide or headshake easily. This is also a good stance for hard braking coming into a corner.

Just suggesting another possibility....

Scott

[Woody_393]

No one's asked, but did the suspension guy set the sag? Did you double check it with your son to make sure it was good?

If memory serves me (it's been known to fail) you want 1/3 of the total rear shock travel in sag. So if it's got 9" of travel, then you want 3" of sag. If for some reason the sag isn't enough, the front end will be heavier then it should be and certainly cause some swappage... ooooh that stuff is scary too, nothing worse then when it starts and you can see if getting ready to buck you off. Too bad none of us has bull riding experience because it might be handy

One other thing, and I don't know if this will work on your son's bike, or if the KX85 even has highspeed compression or not, but after I had my syspension done, I had some problems with head shake and after double checking the settings to see what they were set at, I discovered that the HS Comp was at full soft or turned out all the way. Now the suspension company that did mine did this on purpose, but it certainly didn't fit my riding style, nor did it work well in the "fast/high speed" chop. So the short to my rambling is after I dialed it back in and then back out to 1.75 out the head shake went away.

Like I said, I'm not even sure if the KX85's suspension has HS Comp, but if it does, I'd check it to see what the settings are.

Oh and welcome to We try our hardest not to bite here.