How to add fork oil?

[Supafreak_711]

Ok heres my big question:

Can anyone explain what I need to do to add new fluid to my forks, for someone who has never opened up their suspension (I only have a vauge idea of what is in there).

I already have the bars off and out of the way, do I need to take the fork tubes off the bike? or can I leave them on there and just average out the fluid levels on the front and back of the tube (since the tubes arent straight up and down)

So what do I do after that? I know I will be taking the fork caps off, but after that its an adventure into the unknown for me (first time for everything I guess)

I have a manual, but it seems confusing. I guess I will go out there and see if it makes more sence one I start looking into there. I'll be back in a bit

Thanks guys. I did a search and there wasent much to be found (that I found anyways...)

[Supafreak_711]

Dang... my fork seals are pretty much shot too. So I guess I will do them while I'm at it.

Any works of wisedom on this process would be helpful... otherwise I'm just going to hack my way through it with my semi-fuzzy idea of what to do off the manual.

[grayracer513]

Start by telling us the year/model. Then we can help you.

[Supafreak_711]

Ohh yeah... I guess that would help.

Its an 03 YZ450f

So far I have one tube with the cap off and dust seal off. I'm guessing the dust seal is what people called the "fork seal" and is that needs to be replaced since my seals were leaking. Does the oil seal need to be replaced as well?

Also, following the manuals instructions, it just says to "bottom" out the upper tube in the lower and jerk up and the oil seal is supposed to come out of there. This hasent worked to well (lots of pulling, not much oil seal moving). Can I use a screw driver to safely take the spring off of there and then pull it out?

Thanks again for helping me out... first time for everything I guess.

[Supafreak_711]

Also, I wanted to add that I do have that retaining clip out of there, and got the little spring off of the oil seal. I just havent figured out how to get the oil seal off of there yet.

[grayracer513]

The forks must be removed in order to change the seals.

If you don't have manual, get one here:

http://www.yamahaownershandbook.com.au/?r=0

Start by removing the wheel, loosen the top triple clamp pinch bolts, and loosen the fork caps a full turn. Then pull the fork off the bike.

Follow the manual instructions to remove the cap from the damper rod and remove the spring. Then remove the dust seal, remove the snap ring from on top of the seal, and pull the forks apart per the instructions (extend them sharply)

Skip the part about removing the damper rod. Just leave it in there.

Move ahead to step 6 on page 5-32 ("install: dust seal, etc.,)

You should invest in a real seal driver, or borrow one. You can make one by splitting a piece of PVC pipe, but it won't be as easy to use. This is the only part that gets tough without the right tool. Motion Pro makes one for $60, probably less from the TT Store.

When filling the fork, compress both the inner tube and the damper and fill the fork to the top. Extend the inner tube no more than 8 inches once or twice. Now add oil to cover the top of the damper assembly down in the fork, and run the damper up and down until the air is gone (you'll hear it) and then adjust the oil level.

[Supafreak_711]

The forks must be removed in order to change the seals.

If you don't have manual, get one here:

http://www.yamahaownershandbook.com.au/?r=0

Start by removing the wheel, loosen the top triple clamp pinch bolts, and loosen the fork caps a full turn. Then pull the fork off the bike.

Follow the manual instructions to remove the cap from the damper rod and remove the spring. Then remove the dust seal, remove the snap ring from on top of the seal, and pull the forks apart per the instructions (extend them sharply)

Skip the part about removing the damper rod. Just leave it in there.

Move ahead to step 6 on page 5-32 ("install: dust seal, etc.,)

You should invest in a real seal driver, or borrow one. You can make one by splitting a piece of PVC pipe, but it won't be as easy to use. This is the only part that gets tough without the right tool. Motion Pro makes one for $60, probably less from the TT Store.

When filling the fork, compress both the inner tube and the damper and fill the fork to the top. Extend the inner tube no more than 8 inches once or twice. Now add oil to cover the top of the damper assembly down in the fork, and run the damper up and down until the air is gone (you'll hear it) and then adjust the oil level.

Thanks, your the man!

I still havent gotten the inner tube out of the outer one. Do I just jerk on it and slam it against the end of the tube (basically trying to pull it off of there, but sharply striking that end untill it comes off?)

I have the manual out there with me, but I to was to afraid to brake anything by pulling the outer tube up very hard untill it get stopped. Your saying that that is exactly what I need to do? Pull up sharply on the top tube to "break" it free of the bottom tube?

Also thanks for mentioning I didnt have to remove the damper rod. I was about to go get some PVC to make a tool to get it out.

[Supafreak_711]

Ok I have tried the pulling up on the outer tube to "yank" it off the inner tube. Its making a metallic sounding bang (like im hammering metal on metal). This is what I'm supposed to be doing right? So far after several good hits nothing has seemed to move, thats what has me concerned. I cant afford to break anything (fork seals broke my just about depleted spending funds)

[Supafreak_711]

Ok that is what I needed to do. The sound finally got more and more hollow sounding... which was a good sign.

On to the next step (I really need a computer in the garage...)

[Supafreak_711]

Alright guys, thanks greyracer for all of your help. I got one tube done today and now that I know what I'm doing I will get the other much quicker tomorrow. Also, I made my own seal driver out of a 1-1/2 in pipe clamp (rubber peice that connects two pieces of pipe) and clamped that onto the inner tube. With that on there is was easy as pie to get the fork seals on there. I started off trying to hammer them in with a piece of pipe, but that clamp worked like a charm.

[grayracer513]

Yes, everything but the spring, and fully compressed. I was happiest with the '03 forks at 105-110mm.

[Supafreak_711]

Yes, everything but the spring, and fully compressed. I was happiest with the '03 forks at 105-110mm.

Thanks, luckly thats just about what I set them at.

[tammie]

just reading this post does anyone have a picture of a home made seal driver?? Id like to be able to do my oil fork seals as ive always taken them to the shop and it cost like 75-100 dollars that way.......thanx

[jayh300]

bought one about 2 yrs ago, it is a motion pro i think, all my riding buddies share tools so we all use each others stuff. sure makes fork seal a breeze.

they are different sizes by which size seals you have. I think it was about 55.00.

[grayracer513]

Tammie,

You say, "always", and to me, that implies 3 times or more. The $60 MP driver would have saved you over $170 by now at the prices you quoted, and will do a much better job more easily than a home-made one. If you do the job once more, and never again, you'll still be ahead.

[jayh300]

amen gray... the mp driver will put a seal in in no more than 2 hits.

and will not scratch the fork.

[grayracer513]

amen gray... the mp driver will put a seal in in no more than 2 hits.

and will not scratch the fork.

Sometimes it will. On the '01 250F I had, the OEM seals fit very tightly under the snap ring, and had to not only be bottomed in the pocket, but then driven down a little farther, sort of compressing them into place. I can't imagine giving a seal a beating like that with a piece of plastic, or anything else that didn't fit it right.

[jayh300]

wow... have never run in to that yet...thanks for the heads up.

btw the 400 runs great gray, thanks for your help

jay

[tammie]

ok thanx i'll will buy the real deal...by the sounds of it I thought the homemade one was just as good but if its not then I will buy the motion pro one for sure.....yah ive had fork seals done about 3 times now.....i was never as confident before with working on my bike as I am now so thats why Im finally doing stuff on my own now just aquire the proper tools I need here and there......

thanx guys

[jayh300]

i have read some of the stuff you have done in your posts tammie.

you can handle fork seals.

jay