06 yz450f keeps blowing fork seals


27 replies to this topic
  • 06yamaha450f

Posted February 17, 2011 - 11:47 AM

#1

my 06 yz450f is on its 3rd set of fork seals and they need replaced again. i bought the bike new in late 09 as a dealer leftover. so just last season all this happened. any ideas on what can be causing this or any way to prevent this from happening every 3 rides. i bleed the forks after every ride to get out excess air.

  • grayracer513

Posted February 17, 2011 - 12:28 PM

#2

Some of the OEM replacement seals for the YZF were of a low drag design intended to reduce friction. This they do, but they don't seal very well. The fork seals for an '08 KXF450 fit right in (same fork) and are a good deal more aggressive. You can also order KYB's best fork seals from Dave Johnson at SMART Performance.

Mechanically, chronic fork seal failures can be caused by loose bushings (especially with the factory seals) or by small nicks or burrs on the inner tubes. If you find a nick or scratch that you can feel with a fingernail, you should sand it over with 320-400 grit wet sand paper, using mineral spirits to wet it.

Be sure the dust seals are in good shape, too, and get into the habit of cleaning under them every couple of rides. I always wipe a bead of bearing grease around the fork tube before I pull the dust seals up into place. The grease serves to intercept intruding dirt before it gets to the oil seals, and really does help.

Mud is the arch-enemy of fork seals. Wipe the tubes clean between rides/motos. Even water spots are a problem.

  • 06yamaha450f

Posted February 17, 2011 - 12:50 PM

#3

thanks gray and i forgot to mention that the last 2 times they blew it was the right side only. i was thinking about buying the moose relieve valves to bleed them easier and sooner while at the trails.

  • tpars121

Posted February 17, 2011 - 01:19 PM

#4

I doubt air pressure is contributing to the seal failures and if it is right side only then I would do as Gray said and check the bushings or lower tube for a nick.

  • grayracer513

Posted February 17, 2011 - 03:14 PM

#5

The air pressure that builds in the fork should have very little to do with it leaking, really.

  • brentn

Posted February 17, 2011 - 05:15 PM

#6

Remember that proper fork alignment with the axel greatly extends fork seal and bushing life. You'll know your forks are not aligned after a while as striations will show up on the inner tube where they rub the most.
Alot of people skip this part and then wonder why there seals are blown after only 10 hours of ride time...

  • Ga426owner

Posted February 18, 2011 - 09:18 AM

#7

06s are notorious for leaking fork seals. Grey is dead on - the oem seals do not seal worth a poop...less stiction more leakage :smirk:
interesting that the Kawi KYB are better
What is the best KYB fork seal from Dave at smart Perf for a 06?

  • grayracer513

Posted February 18, 2011 - 09:39 AM

#8

What is the best KYB fork seal from Dave at smart Perf for a 06?

It's probably the KXF seal, but he being a KYB dealer, they all have the KYB PN's on the bag. I can post it tonight if you like, or just ask Dave for the good seals for the YZF.

  • kawi_wowi

Posted February 18, 2011 - 09:44 AM

#9

you should clean your fork thoroughly after every ride and take off your forks and feel them for the tinyest of nichs or scratches and sand them down with very light sandpaper
next time your seals blow make sureall your bushings arent able so come off. also if your spring rates arent set up for you and you bottom out your forks off every jump that could be a contributing factor. setting up harder suspension will make it less likely to blow out seals

  • primerib108

Posted February 18, 2011 - 10:19 AM

#10

I've had good results with MSR seals I put in last year.....prior to that I used oem's and they leaked within a month.

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  • grayracer513

Posted February 18, 2011 - 11:19 AM

#11

I've had good results with MSR seals I put in last year.....prior to that I used oem's and they leaked within a month.

I've used the red MSR's before, and I like their dust seals better than OEM. They were definitely better than OEM from Yamaha, but still not as good as the latest KYB seals from Dave have been.

  • primerib108

Posted February 18, 2011 - 11:34 AM

#12

I've used the red MSR's before


Those are the ones I have, that is good to know.....I did notice the dust seals are a better quality build than the old stockers.

ebay seems to have lots around for cheap too.

  • sledtrash

Posted February 18, 2011 - 07:51 PM

#13

Another thought, when you haul your bike do you use a fork saver?? I know on bikes that are hauled with the forks squished all the way down the seals will blow out very quick.

Dustin

  • richardnoggin

Posted February 18, 2011 - 07:53 PM

#14

One more idea is that you might have a burr or scratch on your fork,that is what i found on my forks,a rock or someting put a small burr in it and the only way i found it was by feel!!

  • mliebal

Posted February 18, 2011 - 07:57 PM

#15

One more option is to tighten the seal spring. Just pull the dust cap down and use a small scredriver to pull the spring that goes around the seal up in the fork. Once it is down the leg find the end of the spring and unwind them. Then clip off about 1/2" from the female side of the spring, reassemble. This has done wonders multiple times for extending the seal life. It just increases the preload on the seal that gives the sealing.
Good luck

  • grayracer513

Posted February 18, 2011 - 09:27 PM

#16

Another thought, when you haul your bike do you use a fork saver?? I know on bikes that are hauled with the forks squished all the way down the seals will blow out very quick.

Dustin

That falls under the heading of Bovine Scatology, or as the Marines in the field say, "BS".

I haul mine around with the forks compressed all the time, and have no such problem.

  • ktmexc300

Posted February 18, 2011 - 09:36 PM

#17

tired of fooling around with forkseals? I know exactly how you feel. try racetech fork seals and buy a 20 dollar fork saver. or make your own fork saver with 2x4's. It worked for me and I havent had a problem since!!!!

  • grayracer513

Posted February 18, 2011 - 09:39 PM

#18

I haven't had a problem since I started using the latest KYB seals and I never use a "fork saver".

  • coreyl

Posted February 18, 2011 - 09:55 PM

#19

i have been using msr fork seals and amimpressed so far.

  • YamaLink

Posted February 19, 2011 - 07:31 AM

#20

Hard water deposits got my friend for a few blown seals until he started wiping the forks spotless after washing.





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