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Speed wobble.

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Posted by: Blackcat---------------------

Okay my bike does okay over the flat ground and everything but when I get on the woops my front end shakes back and forth. Not a continues back and forth just an occasional. I'd like to be able to go fast over the whoops but this stuff is scary . Any Idea on what it could be? I havn't took anything apart or checked it out yet as I would like to get some feed back first but I can say that everything looks okay. Thanks in advance.


Posted by: adam728---------------------

First thing first, have you set the rear sag for your weight? It will make a big difference in how your bike handles.


Posted by: Blackcat---------------------

I will check that as soon as my mom gets home. As I need a second person to actually measure. I read around here 105 mm does that sound right?


Posted by: kurt15---------------------

how's your front wheel bearing? i could be wrong but if its worn the front wheel will wobble... correct me if im wrong, just trying to help..


Posted by: Blackcat---------------------

The front wheel seems solid and the bearing spins good. I checked the sag and it was at 4 inches which equals 101 mm so it's not that far off. I would also like to add that my rear shock needs rebuilt. It is leaking a small amount of oil. When I say small I mean small amount. But I don't know how long it has been leaking. So maybe there is no oil in it. But it feels okay. Any other ideas I'm going to adjust the rebound and compression dampening on the front when I'm done with homework but I'm sure there all stock, just like the shock on the rear is adjusted to stock.


Posted by: Sand_man---------------------

my sag is set around 100mm. i ride a yz125, im about 135lbs. so make sure ur sag is set correctly. but when i got headshake i turned in the compression screw out 2 times, making the compression a little softer. that helped alot. also make sure your holding onto the bike with your legs gripped onto the side of the tank. hope that helped?


Posted by: Blackcat---------------------

Okay the front compression screw or the rear.


Posted by: Sand_man---------------------

the front compression screw on the forks, 2 clicks softer should help alot.


Posted by: Blackcat---------------------

Okay I took the forks off today and changed the fluid filled the forks back up to factory specs. I gave it 4 clicks softer. Seems like it helped a little bit. Maybe I'll give it two more tomarrow and see what that does. But for the most part it still wobbles. Anybody else have anything to say don't be shy. I am really determined to get this worked out.


Posted by: Sand_man---------------------

hmm, thats weird...what kind of terrain are you riding on? track, or just feilds and stuff?


Posted by: Blackcat---------------------

Dirt roads hills and Whoops. I really feel like the bike is working against me. When I go over whoops it will go alright for a bit then the front will shake and the back tire feels like it's trying to bounce in front of the front. The bike also feels really un manuveralbe. Any turns in the trail that I am riding on and I have to slow way down just to make the turn. And when I ride down dirt roads the front will just shake for no reason.


Posted by: rpm12505---------------------

Try FactoyConnection.com They have a trouble shooting section that might help. You may have to go the other direction with the clickers. Sorry I couldn't link it, good luck.
HEADSHAKE / HARSHNESS:
FORK - Is generally caused by too much compression damping in the forks. Soften compression 1-2 clicks. Lighter riders for the size bike you are riding may find it necessary to change to softer fork springs. Too much rebound damping can also cause a “packing” situation in which the damping holds the forks down in a stiffer area of the travel than is needed. Soften rebound damping 1-2 clicks. Other causes can be : a) improper fork installation or binding of the fork. b) improper shock set up which causes the fork to ride too far into the stroke.
Hey there it is


Posted by: BSWIFT---------------------

Quote:
Originally Posted by Blackcat
When I go over whoops it will go alright for a bit then the front will shake and the back tire feels like it's trying to bounce in front of the front. The bike also feels really un manuveralbe. Any turns in the trail that I am riding on and I have to slow way down just to make the turn. And when I ride down dirt roads the front will just shake for no reason.

Blackcat, what bike, how much do you weigh, stock suspension? If your rear shock is causing you to kick side to side, I would start looking there. If it is in need of service, you are better off getting that resolved before trying to isolate your head shake. Any component that is not working properly will not be consistant and will leave you chasing your tail to find the actual problem.
Your sag numbers sound good but how does the bike handle braking bumps and square edged bumps? It really sounds to me that the front and rear our out of balance. The rear is likely packing and transferring the harshness through the frame to the front end. I would recommend that you first service the rear shock, make sure your spring rates fit your riding condition and your weight, then start from scratch and adjust per trial and error.


Posted by: Blackcat---------------------

Yea the rear shock is leaking fluid. It started off small but now it is slowly getting worse. I am going to have to have that fixed first. I also noticed there is vertical movement in the bearing at the top of the shock so that is going to be fixed as well. Hopefully I'll have all this done by friday and I'll be able to take it out for a ride and see if that improves anything. I'll be posting back here pretty soon.


Posted by: 95xr250---------------------

the wooble sounds normal to me i have always done this even back when i had a brand new bike


Posted by: BSWIFT---------------------

What is your weight?


Posted by: Blackcat---------------------

I weigh 170 give or take a few. And yes everything on the bike is stock. I also noticed that there was play in the top bearing of the shock causeing some vertical freeplay. I ordered the bearings today. Would this have made a difference? Also as for the breaking bumps and square edge bumps it seems like it handles okay. I don't have nothing to compare it to but they don't seem to bother me. The bike does want to endo a bit on the smaller jumps though. I have to pull up and gas it at the same time to avoid this.



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