Jump to content
Sign in to follow this  

yz 250 constantly blowing fork seals! helllpp

Recommended Posts

I have had this problem of all recent yamaha's i have had! i literally have to replace the seals every 10-15hrs!

It;s costing me a fortune! i never encountered this problem on any of my Ktm's .

Whats the deal with the yamaha's doing this?

I thought about running seal savers? do these do any damage to the fork leg chrome? i ride in a lot of mud , suppose that can't be too healthy for the seals but it's gone beyond a joke now. i have had yz 125-09, yz 250 -09,10 and 11! they all do the same thing!

I have undone the dust cover spring last night ,chopped 5mm off , i will see if that does anything to stop the leaking.:bonk:

Share this post


Link to post
Share on other sites

hi aled

had the same problem with my 06 ,when you replace the seals pop the old springs out of the old seals and install in new seals so you have 2 springs in each seal worked for me.

but now i'm running ohlins but i did same trick with these.

cheers jk

Share this post


Link to post
Share on other sites

I read that yamaha is proud to use less friction on their seals. That aside most seals are just dirty and need cleaning which can be done from the outside. I got feed up with that cleaning and use sealsavers. No more problems now.

Share this post


Link to post
Share on other sites

good tip that jason! will try next time i replace the seals. i have cleaned the inside of the seal last night with a thin strip of plastics.. think they have stopped leaking,. at least for a bit anyway! i change seals like i change airfilters it seems! lol

Share this post


Link to post
Share on other sites

When you install your forks are you making sure they aren't bound up on the axle and they're parallel?

Most people bang the axle in with a hammer and tighten it up.

You need to install them methodically, making 100% sure the forks are in their natural position.

Share this post


Link to post
Share on other sites

yes i have been know to bang the spindle in at times ,they seem to be very sensitive forks to whatever you do with them

Share this post


Link to post
Share on other sites
yes i have been know to bang the spindle in at times ,they seem to be very sensitive forks to whatever you do with them

There you go, answered your own question.

Put the front end together correctly and you won't have a problem.

Share this post


Link to post
Share on other sites
I read that yamaha is proud to use less friction on their seals. That aside most seals are just dirty and need cleaning which can be done from the outside. I got feed up with that cleaning and use sealsavers. No more problems now.

Ditto here. The only way to go.:bonk:

Share this post


Link to post
Share on other sites

I was told by Dave at smart performance that the 2010 and up NOK ( i think oem brand) are the best made seals. He says there are 4 different models and the newest are the best. Also when you clean your bike dry off the shinny part of the fork, otherwise the water dries and the deposits are like sharp crystals that do damage. Also he sugests spraying silicon on the clean forks, says forks naturally leave a coat of oil when compresed and by cleaning you remove that layer.

Share this post


Link to post
Share on other sites

gotta remember to bleed your forks before/after everyride, especially if your riding area's elevation is below your storage area, if you leave the bike with postive pressure inside the forks its always going to try forcing oil out of the seals.

Share this post


Link to post
Share on other sites
There you go, answered your own question.

Put the front end together correctly and you won't have a problem.

So true.

Also if you crash the bike and twist the forks in the clamps you should re-align the forks in the clamps and re-align the fork legs to the axle.

Share this post


Link to post
Share on other sites

Hone the chrome portion of the forks during a change out.It will have less friction and will "hold oil" to lube the seals.

To do this,spin the lowers in a lathe or use a drill press and a expantion test plug on the open end to chuck it up,Use the slowest setting on the drill.Then use a 800 grit abrassive wet\dry paper with light oil.

and run it up and down.

This also gets rid of any micro nicks that kills seals.

Works great!! People bring me their forks that the "real shops" have done several times.

The only problem iv'e had is when they bring me Alls Balls seals,,pure junk! I won't install those anymore.

Share this post


Link to post
Share on other sites
When you install your forks are you making sure they aren't bound up on the axle and they're parallel?

Most people bang the axle in with a hammer and tighten it up.

You need to install them methodically, making 100% sure the forks are in their natural position.

I'm guessing this^^^^^^

I went through a couple sets of fork seals quickly by not following the manual when reinstalling the wheel assembly. On my yami's I need to hand tighten the axle nut, take the bike off the stand, compress the suspension up and down 15+ times, tighten the pinch bolts then torque the axle nut. This will keep the lower fork tubes from being pulled slightly inwards causing the fork seals to fail.

Share this post


Link to post
Share on other sites

There are a few things that will help:

1. Use Honda Seals from a 2010-11 CRF450. They're spec is a little better than Yamaha's, for whatever reason.

2. Use a pair of your wife's silk panties (or nylon) to run all over the fork tube when you have it apart. If there is ANY snag at all, it has to be buffed out.

3. Be very careful installing the new seals so you don't cut the lip. I would guess some folks out there induce a problem on install.

4. Make sure your fork bushings are not worn out.

5. Install and align your forks/front wheel properly.

6. Dry your fork legs after washing the bike. As others have said, hard water deposits can be very sharp.

Share this post


Link to post
Share on other sites
Use a pair of your wife's silk panties (or nylon) to run all over the fork tube when you have it apart. If there is ANY snag at all, it has to be buffed out.

Will my old streaked cotton whitey-tighties work instead? I don't think my wife will let me steal her silkies for motorcycle maintenance! :bonk:

Share this post


Link to post
Share on other sites

have a good suspension guy install the factory seals. backyard mechanics usually damage them while sliding them on. My yz's went out immediatly on my new 06. Had my suspension guy do a re-valve and they lasted hundreds of hours and were still not leaking when I sold it.

Share this post


Link to post
Share on other sites

Like i said before, Smart Perfomance states "90% of the time fork seals leak besause the bike was washed". Washes away the protective layer of lubercation. Hard to believe (90%), on the flip side, if you think about it it makes sense, you need lube.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

Sign in to follow this  

×