Front End Gose Crazy

[eagles22793]

I have a 2000 YZ250 dirt bike I bought about a month ago and the front end gose crazy sometimes when I am riding it. The hole front end gose back and forth by it self and I dont know how to make it stop. Can some one give me some advice on how to fix this?

 

[julien_d]

rebuild forks, replace front wheel bearings, replace steering stem bearings, set up your forks properly.

one of those will probably fix it. Kind of hard to narrow it down with the information you've provided though.

 

[eagles22793]

I dont know how to tell if the forks need to be rebuilt or the stem bearings need to be replaced but it already has new wheel bearings and the front forks are not set up for my weight because I dont know how to set them up right. I dont know much about the front end because I never had to mess with them but I know the rest of the bike.

 

[TRexRacing]

You may get better results and answers is you look at this.And read a bit.

http://www.dirtrider.net/forums3/forumdisplay.php?f=29

 

[whenfoxforks-ruled]

Fork height in the triple clamps, race and static sag, your weight, ground conditions, fork and shock mechanically sound, and what springs are on it now? This information could be relevant.

 

[eagles22793]

How do I adjust the forks for my weight and I already moved the fork height down and it made no difference. I only weigh 133 and I am 5' 9" so I am not that big for this bike but can controll it with no problem. The handlebars go crazy only at high speeds and not all the time.

 

[RM85rider123]

How do I adjust the forks for my weight and I already moved the fork height down and it made no difference. I only weigh 133 and I am 5' 9" so I am not that big for this bike but can controll it with no problem. The handlebars go crazy only at high speeds and not all the time.

133 lbs. on a 250 :yikes: . thats you're problem right there. JK :cool:

 

[helio lucas]

I dont know how to tell if the forks need to be rebuilt or the stem bearings need to be replaced but it already has new wheel bearings and the front forks are not set up for my weight because I dont know how to set them up right. I dont know much about the front end because I never had to mess with them but I know the rest of the bike.

eagles, it´s the same.
1: lift the front wheel of the groud, grab the wheel and try move it back and forth. any play and you need to ajust\replace the steering bearings on the top of the steering head.
2: there are several tutorials to rebuild the suspension on dirt bike. on this forum, on video web sites and even on service manual.
3: when aligning the front wheel you need to be sure to align the axle, or the forks may bind and cause severe wear and loss of control. once again it´s on the service manual.
4: tight the spokes. half a turn each time, 1 spoke yes, 2 spokes not. mark the already tight spokes so you could tight all of them just 1 time before going the second round.
5: after everything verified and repaired what needs to be, check your bike geometry with static\loaded\unloaded sag.

theres is more about dirt bike than just ride until it breaks! :nod:
get the service manual of your particular bike, they are VERY hepful.

go to eric gorr web site, http://www.eric-gorr.com/, and chek the FREE samples of his great book "off road performance handbook". there is a guide for your bike every single problem. after that, just buy the book...

and, just hang on to handlebars :cool:

 

[eagles22793]

I checked the stem bearings yesterday before I went riding and they seem to be fine and I know that the forks dont need to be rebuilt but I did notice that there is a directional front tire on this bike and it is on backwards. Could this be the problem?

 

[High Lord Gomer]

What you're experiencing is called "head shake". If you've already moved the front forks down to where the top of them are flush (or close) to the top of the top triple clamp, the next thing I would check would be the preload on the rear shock.

 

[whenfoxforks-ruled]

Nice try. What is the rear sag set at? Set the rear sag first. Then check the static sag, this will tell you if you have the proper rear spring. The front springs needs to match. At 133 pounds, you will likely need revalved to match the new spring rates.

 

[eagles22793]

I did not mess with the rear shock yet because I didnt think it had anything to do with this problem. The rear shock it set up for an 180 pound rider and feels pretty good for me when I am riding. I still have no idea on how much to turn the screw on the top of the front forks or the rebound on them?

 

[whenfoxforks-ruled]

With the rear end set up stiff, it will push on the front end. Check and set the rear sag, for your own safety.

 

[eagles22793]

I am going to put the front tire on the right way because I know that has to make a difference somewhere and I will soften up the rear sag a little because I like it a little harder then for my weight

 

[whenfoxforks-ruled]

4 inches for MX, SX 3 1/2.

 

[eagles22793]

Could there be anything else that might be wrong to make the front end go crazy. It has good stem and wheel bearings, fork height is adjusted flush with the triple tree and the forks dont need to be rebuilt. Can someone tell me how to set the static sag on the front forks?

 

[whenfoxforks-ruled]

Static sag on the forks, that would be new. Look, you get the proper weight spring in the back, get the static sag within range. Then you will know what rate springs to put in the forks, easy enough. Check out MX Techs website, they have a spring generator to tell you what springs you should need.

 

[eagles22793]

I am good with the stock springs that are on it now. There is no point of changing the springs if I dont need to. All these people change these springs for know reason and they are not even good at riding. Go to a track look at the nicest bike there and I bet you he sucks at riding.

 

[jsantapau]

What you're experiencing is called "head shake". If you've already moved the front forks down to where the top of them are flush (or close) to the top of the top triple clamp, the next thing I would check would be the preload on the rear shock.

 

[jsantapau]

With the rear end set up stiff, it will push on the front end. Check and set the rear sag, for your own safety.

 

[jsantapau]

have you checked the rear yet?

 

[julien_d]

I am good with the stock springs that are on it now. There is no point of changing the springs if I dont need to. All these people change these springs for know reason and they are not even good at riding. Go to a track look at the nicest bike there and I bet you he sucks at riding.

Dude. You seriously need to stop asking for advice, period. You've been told how to begin fixing the problem. If you don't want to do that, then just go ride it set up completely wrong for you and leave these guys alone. They have better things to do than waste time trying to beat information into your head. Correct suspension setup is the single most important aspect of your bikes handling, and 99% of that starts with setting the rear sag CORRECTLY. Just do it already. It takes about 15 minutes.

 

[longtime coming]

Then find out what all the stock clicker settings are and start there. You are too light for a stock 250 spring set-up. :bang:

 

[whenfoxforks-ruled]

IF, the rear sag is 4", and the static sag is 1 1/4", you need a softer rear spring, and fork springs to match. The way it is set up now, the rear end is too stiff and pushing on the forks too much..... The only way for your bike to handle even close, is put the proper springs in. It has absolutely nothing to do with a riders abilities and spring rates. Re-valving for faster riders to be sure, springs no. Head shake at top speed is a sure ticket to the emergency room, sooner or later. Put all your gear on, weigh yourself and check MX Techs spring generator, put all your gear on and have 2 people hep you double check the race sag and static sag, THEY WILL BOTH TELL YOU TO CHANGE THE SPRINGS! Sometimes you can get them off fleabay cheaper, or go for bust and order some titanium springs, no actual benefit, other than weight and bling power. And by the way, do you release the air in your forks with the wheel off the ground?

 

[helio lucas]

one thing i forgot, a bad tire (old,beat one), a wheel that is not properly aligned, or a bent\untrue rim may cause some headshake at cetain rpm...

if you are fast with a untuned suspension, try setting the suspension. it will make twice faster!!! realy!!!