Folk oil

[ZX9Rider]

How do you check/change/test that your forks are full and in good shape?

This is for a yz490.

[Sortarican]

Depends on what kind of folks you used to make oil.
(Bad folks are actually oilier than good folks.)

J/K,
I like to change mine at least every other year, every year if you do hard riding.
The process is pretty much universal, with oil weight and volume varying.

Here's a good basic article on it:
http://oldmanhonda.com/MC/Rforks.html

[ZX9Rider]

Thanks. I was following it until it got to draining the old oil. Then it was all Greek to me.

[Sortarican]

Here's the schematic for the YZ fork (1988 ).
Let me know if it's a different year.

It looks like you're lucky and it has a drain screw at the bottom. (#18,44)
http://webservices.motorsportdealers.com/parts/partImages/YAM/2/02/0354/0019.Gif

You'll need to fill it through the top end caps (#22).
Extend the forks fully and remove CAREFULLY!!!, They're under pressure.

Not sure what weight oil to use but any shop should be able to tell you the factory spec and you can play with heavier or lighter weights.
You fill them either with a specific amount (wet/dry) or more typically to a specific level below the top of the fork (with forks compressed top off to 'X' cm below top of tube).
These specs will be needed.
You can also remove the top caps before draining and measure the level of the old oil before draining.
Then refill to that point after draining if the suspension felt OK previously.
(Add a couple extra cc's to account for what sticks to the springs when you remove them.)

Here's another article mentioning some fill issues:
http://www.ta-deti.de/ta/forkoil.html
When refilling you should also work the suspension up and down (slowly) to get oil into the valves and let them sit a while to allow air bubbles to rise before taking your final measurements.

Hope this helps.

[ZX9Rider]

Thanks. I think this bike is a 83 or 84. I get this springy noise from it whenever I press them down. I don't know if thats normal?

[Bueller]

You're gonna put your eye out on that monster! :lol:

And no, that doesn't right (springy noise).