RM 250 Head shake

1

1998RM250

Member
Nov 5, 2008
426
0
Hey guys I recently had a shop install new fork seals on my 01' Suzuki RM 250 (kyb forks) and since I got it back it has some serious head shake through the whoop section. When on the throttle through the whoops the front end has alot of head shake and the rear end wants to bounce out side to side on me as well. I'm an average 165 lb rider, and from what I know has stock springs, any advice? Oh btw the rear shock has been swapped for a showa, not sure if that makes a difference? Thanks
 
W

wake_rider

Member
Feb 21, 2007
481
2
Maybe they put the forks high up in the triple trees, putting more weight on your front end? Check to see if your forks are much higher in the clamps than you originally had them.
 
1

1998RM250

Member
Nov 5, 2008
426
0
Thanks for the response, they seem to be in the right position from the markings on the tube where they previously were. It's bad because not only does the front have bad headshake, but the rear likes to get out on me from side to side when accelerating through the whoop section!
 
C

Chili

Lifetime Sponsor - Photog Moderator
Apr 9, 2002
8,062
17
You had no headshake issues prior to getting new fork seals? There is really nothing in changing a set of fork seals that is going to cause the front end to head shake or the rear end to dance around. I'd drop the forks in the clamps some to combat the headshake and stiffen the compression and maybe slow the rebound in the shock a bit to try to tune out the back end dance.
 
J

_JOE_

~SPONSOR~
May 10, 2007
4,697
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Same guy that did your jetting? :whoa:

Check the sag on that shock. Why did you swap it out? Has it been serviced? Where did it come from? Are the front and rear spring rates matched?

You can't just swap out suspension parts and expect them work fine. You may need to send the forks and shock out to be matched to each other, the bike and you. Front and rear must work together as a balanced package to get the handling right.
 

whenfoxforks-ruled

Old MX Racer
~SPONSOR~
Oct 19, 2006
8,129
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Merrillville,Indiana
Make sure all the clickers are where they should be, and one side is the same as the other. The rear did not change since you have owned it/had the fork seals done? There is no reason to change the inner reservoir of oil, but the outer oil level could be altered. When you release built up air out of the forks, make sure the wheel is off the ground.
 

2-Strokes 4-ever

~SPONSOR~
Feb 9, 2005
1,842
4
Missouri
Lighter weight oil?
Less oil than before?
Different clicker settings?
As mentioned... different fork height?

5W oil should be OEM.
Manual will tell OEM oil height.
Go back to stock?... or slow down comp and speed up rebound (fork).
Even 3mm will make quite a difference in forktube height.

I'm assuming you didn't change shock settings?
Speeding up comp and slowing rebound will effect the way the fork performs.
You dialed in with 100-105mm rearend rider-sag?

Suzukis are fast-handling, turn-on-a-dime bikes.. they like steering dampers.
 
1

1998RM250

Member
Nov 5, 2008
426
0
I know the guy who did the fork seals adjusted the clickers, and the seemed a bit stiff so i went 3 clicks softer. As for the rear I will have to check the sag height again, but my old kyb shock blew an oil seal and I happen to find a good deal on this one from an 03' RM 125. I haven't really messed with the rear shock settings much, it just shakes it's head and dances out side to side so much! One thing I found out this morning is that the head bearing is slightly worn, not sure if that will have a huge effect?
 
J

_JOE_

~SPONSOR~
May 10, 2007
4,697
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I'd suspect the shock. Too light of a spring or wrong preload/incorrect sag.

This is another area you should learn to tune yourself.
 
1

1998RM250

Member
Nov 5, 2008
426
0
I think your right joe, the rear end kicking out side to side probably has to do with the front end getting out of control. Hey at least I'm trying to learn, even though I ask a million questions!
 
D

dirt bike dave

Sponsoring Member
May 3, 2000
5,348
3
What is your sag?

How about the free sag (how much the bike sags under its own weight after you set the sag with you on it).

FWIW, too low an oil height in the fork will make it easier to bottom the fork. If the fork is hitting the next whoop, more compressed you could get head shake where you had none before.
 
1

1998RM250

Member
Nov 5, 2008
426
0
Maybe i should do a search more on sag height, I just left it how it was after
I installed this shock. Seems the bike sits quite a bit lower then before on its own weight, but I left it because I can touch the ground better. How do I set it up right, any good links?
 

whenfoxforks-ruled

Old MX Racer
~SPONSOR~
Oct 19, 2006
8,129
2
Merrillville,Indiana
The 125 shock may work on a 125. You would likely need a new spring, and valved for the 250. I do not know if putting thicker oil would be an easy fix? After setting the race sag, see what the static sag is. That is the 1 to see if you need a spring.
 
1

1998RM250

Member
Nov 5, 2008
426
0
I figured they would both be the same since they are just about the same weight, and frame etc. Seems to work pretty good, except the whoop section.
 
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