'04 Kayaba Clunk when Top Out

[markpr]

Hi,

Just had my suspension rebuilt front and back on my '04 YZ250. The suspension is working great so far in the first few hours of off-road riding and looking forward to taking it to the track.

I've noticed though a "Clunk" when I first top-out the fork and then compress through the first few inches of travel. I also pulled the forks off the bike and both forks rattle when shaken (springs?) and also make some noise (rattle) at the top of the fork uppers.

Looking for some help if this is normal and nothing to worry about or whether I'm facing some premature wear or other failure if it's not looked at. Going to call the suspension company tomorrow but as I have these things off now any info would be helpful (if anyone has 04 kayabas they could try this with too..)

On the "Clunk" sound - I also stripped all the plastic and anything obvious to rule out anything around the forks making the noise. I also rule out the wheel bearings as the cause of the sound (in good condition) and don't think this is coming from the front caliper. The steering head has a new set of bearings/races and everything has fresh grease. I can create the clunk sound by applying the front brake, pulling back on the bars (to fully extend the forks) and then pushing down to compress the forks (keeping the brake applied). I get the clunk sound when doing this slow or fast. I tried the same thing on a 2005 YZ250 and I can't create the sound there (I know these are an updated fork so it may not behave the same).

thanks for any help - Mark

 

[whenfoxforks-ruled]

Did you check the air relief valves for air build up? And you do know to do this with no weight on the fork?

 

[markpr]

I forgot to mention that, yes I bled the air out of the forks and did this while the bike was on a stand. We also opened up one of the forks bleed valves after the fork was off the bike and there was no additional air in there....

 

[whenfoxforks-ruled]

There are bumpers to soften topping out, and the rebound damping. Where is the rebound adjustment set at? And you are sure its not binding? Overtightened pinch bolts? Loose pinch bolts and or steering stem nut? Then, I would be on the phone, AND not riding it! You did write that they had just been serviced? Something is loose or broke.

 

[markpr]

I have rebound set at 10 and although pinch bolts are at torque settings (and with all new bolts) I did not try to see if the "clunk" would occur with the bolts just hand tight. I also followed the fork install procedure that's documented here. I agree, not wanting to ride this until I have the all-clear from the suspension company and have less than 3 hours since a complete rebuild...

What about the rattle with the forks off the bike, is that normal?

 

[whenfoxforks-ruled]

What about the rattle with the forks off the bike, is that normal?

Now you got me there! I would figure there would be some amount of play in the spring? You used a torque wrench and followed Jeremy's directions for properly setting the front end? Then something is wrong.

 

[_JOE_]

I recall seeing a few threads about this issue. I have a buddy with an 05 yz250f who developed the same clunk after a seal/bushing replacement. As far as I know he's still riding it like that. I haven't heard anyone come back with a solution. I would definately call the company that serviced them.

As for the rattle when shaking them, some setups have a bit of a gap between the spring and seat when unloaded. That would allow the spring to move around a bit causing the rattle. They certainly need to come back apart ASAP to see what's goin on in there.

 

[markpr]

I spoke with the company this morning and they do believe this is normal for the same reasons (Joe). There is a gap that can cause a rattle of the springs and the forks when they top-out run a little bit of negative pre-load that can be causing this clunk sound. They suggested taking off the top-cap and having a look which will confirm nothing is loose and also give me some familiarity with the internals.

I did use a torque wrench and it was Jeremy's instructions for setting up the front end that I used. I even used a digital caliper to set the fork height even on both sides so feel pretty good about the installation. If this is all just normal I am happy.. ( I don't need a stealth fork !)