Replacing Fork Seal YZ250F

 

I'm looking at buying a '06 YZ250F. Bike's in excellent condition but I have
1 concern. The owner had the fork seals replaced last October at a good
shop. The left seal is leaking which leads me to believe one of 3 things.
The forks look straight and clean from the front or back and the bike rides
well.

1) Shop did a poor job (less than likely)

2) Tube is scratched or damaged (how can I easily check this before buying?)

3) There is debris in the left seal.

Any input here is appreciated. Is this a job I can do at home, replacing
that left seal? I'm pretty good with bikes but never removed a fork.

Thanks!

 



I think that is more likely than you think.


You should be able to see or feel any scratch that could be causing
this. The dust seal (the thick rubber doughnut at the bottom of the
upper fork tube) can be slid down to check the last bit of travel
nearest the oil seal. And make sure the forks are fully extended--put
the bike up on a stand with the front wheel off the ground. Take a thin
slotted screwdriver, wedge it between the dust seal and the upper tube
and GENTLY twist. The seal will pop down and you can see up into the oil
seal area.

An out of round lower tube is harder to identify, but pretty unlikely.


Probably most likely. I've had good luck cleaning out debris with a thin
paper business card or piece of 35 mm film. Pull the dust seal and
gently work the film up into the junction between the oil seal and the
fork tube. Work it gently up and then down with a spiraling motion,
going all the way around the tube. Motion Pro actually makes a device
for this...


Yes, you can do it. I'd rate it as slightly more difficult than doing a
2-stroke top end. You'll probably need a couple of specialized tools--a
damper remover allows you to pull everything completely apart, but some
people skip that and just hope they get all the crud out. Not sure, but
you may need a tool to unscrew the fork tube caps--either in 06 or 07
they changed to a recessed fork cap. Motion Pro has both of these.

I don't trust others to maintain my bikes. There are always exceptions,
but dirt bike mechanics are not generally highly valued by the average
dealership, and anyone who is good at it won't last long in a dealership.

Good luck!

--
Charles
'99 YZ250

"It's bad luck just SEEin' a thing like that..."

 


Great advice across the board, thanks for that. When I go to close on the
bike, I'll start with removing the dust cap and looking for any obvious
issues. If nothing's obvious, I'll buy the bike and use the film negative
method 1st and if that doesn't work, pull the forks. The bike appears to be
in excellent condition, an '06 for $2,500. Fair price?

 



Sounds like on OK price, just figure there's probably something on it
that needs fixing, so don't be surprised :)

--
Charles
'99 YZ250

"It's bad luck just SEEin' a thing like that..."

 


Yeah, the guy seems to think he's doing me a favor as his ask was $3k, he
wanted $2.8k and I won't budge past $2.5k. We're supposed to close tomorrow.
The thing that's wrong with it, in my mind, is the leaky fork and 1/2 run
out tires. I'm hoping that's about it. She looks clean otherwise.