Adding fork oil

[KKXR400R]

I need to add 20cc's of fork oil to bring it up to 370cc's. Can I add it in the air release hole of do I need to slide the out fork down and add it there?

-Kevin-

[KKXR400R]

bump

[MXtras]

You can add it through the hole.

Scott

[KKXR400R]

Scott, thank you for the response. I took the liberty to pull the fork off last night to change the oil in the cartridge, this was the first time I've ever done this. For some reason I've been pretty hesitant to try this. After looking at the internals it look like the bleed hole passed through into the fork tubes.

I hope I got the cartridge oil replaced correctly. I drained the oil and cleaned throughly. Put 180 ml of 5w fork oil back in and bled the air by pumping the piston rod a few times, then reassembled the forks. The only thing that confused me was the measuring part. If they give you the oil capacity for the cartridge, why would you need to measure the oil height? Did I did something wrong by not measuring it?

-Kevin-

[MXtras]

I always measure. Why? I don't really know now but with the older bikes you had to.

What you are actually controlling by measuring the height of the oil is the air space above the oil (which gets compressed and helps the spring, essentially) and by measuring the actual level instead of measuring the volume of oil installed, you will compensate for manufacturing discrepancies within the fork. Personally - I find the forks are manufactured to such tight tolerances these days, I doubt there is more than a CC or two different between any two forks of the same model - there just aren't that many surfaces that are not machined inside of a fork - therefore the volumes are pretty darned close.

Measuring the oil distance is still the best method because a smaller air space dimension will increase the air pressure above the oil and make the fork feel more firm. This distance can be adjusted to alter the feel of the front end.

Measure the distance and make the two forks exactly the same to avoid issues. And make sure you record the dimension somewhere for future reference. This is best. See your manual for the procedure and for the limits of this dimension - too much oil is a bad thing.

Scott

[KKXR400R]

Thanks again. You have a been a great help. I'll measure the height tonight.

-Kevin-

[Woody_393]

Are your CR's forks Twin Chamber?

[KKXR400R]

I don't know...I think...



Does this help?

-Kevin-

[Woody_393]

Yes, they are TC forks.

For the internal chamber, you just fill it to where the books says to go to, and then put the stuff back in and it should bleed off the extra. I have never used a ratio rite or anything to fill the internal one.

For the outter chamber, you measure the amount in a ratio rite or whatever, and fill it.

Anyway, I know I'm late, and you are probably already done, just wanted to add what I normally do.

[KKXR400R]

I have never used a ratio rite or anything to fill the internal one.

So measuring it would be a better route? I just put the capacity the book said (180ml), bled it and put her back together. Besides measuring the height, Sound right to you?

-Kevin-

[Woody_393]

Yeah, the easy part about the internal chamber (unless you don't add enough) is that when you install the valving it pushes out all the excess oil so you can't add too much.

[P1M]

Originally Posted by Woody_393

Yeah, the easy part about the internal chamber (unless you don't add enough) is that when you install the valving it pushes out all the excess oil so you can't add too much.

Kevin, Woody is correct. I have measured to what the book says and when I push the valve in I always makes a huge mess always so I gave up long ago and just fill it. But remember to bleed the cartridge

[KKXR400R]

Thanks, I didn't have any oil come shooting out. Very clean, no mess. Tracy liked the way the bike handled and said the front felt plush but wasn't bottoming out.

-Kevin-