CC's versus MM's ?

[Garyb]

OK - I want to change the level of my fork oil and don't want to pull off the forks to do it. I will add oil through the air bleed hole.
So if i want to raise the level 5mm, how many cc's is that ?
This is for 2002 43mm WP legs on a KTM 250 exc
Thanks to the mathmeticians out there !
Gary

 

[Strick]

You are mixing a distance measure, versus a liquid measure. Does not compute! CC's can be converted to ML. If the level of measure were whole ( i.e. nothing in the chamber but fluid), you could calcuate the amount of fluid in cc's or ml it would take to fill that 5mm height space in a 43 mm fork tube. Actually, a very easy calculation.

I can only give the explanation and not a solution for your problem, because, unless I am mistaken, the rod is taking up some space with the tube that is being filled. With the measure of the tube, you could then subtract the difference of the rod measurement from the solution that would appear from above, and you would have your answer.

 

[Garyb]

Ahhh Strick...you're giving me a headache...maybe there is someone out there who has been through this before :D
Gary

 

[marcusgunby]

5cc is roughly 5mm on a 43mm fork.The numbers dont matter as long as the outcome is correct-less bottoming and no harshness:)

 

[Strick]

Marcus, your estimate must come from experience. I too have raised the height in the 43mm forks (5mm), but I did it in conjunction with a fork oil change. So, I did not measure (in cc's) how much oil it took to move the additional 5mm.

Gary, change the fork oil completely and measure the height then. Do not believe for a minute that every fork from the factory is set at the right height to begin with. If you have many hours on the forks at all, you owe it to yourself to do an oil change.

 

[Garyb]

Strick - I changed the fork springs and set the oil height before I rode the bike, and have changed it again since then (in a 3 week period) I have only ridden it 1 time (harescramble)since then..
I'll try the marcus solution:scream:
Gary

 

[marcusgunby]

If i was starting with an unknown fork(ie new to me) i would do a oil change and set the oil height low(assuming it wasnt bottoming)then i would add oil like described until i got the desired result.I like using oil heights and not clickers to control bottoming as i beleive this is a superior set up.Like Strick says new forks are rearly set well from the factory.BTW i dont muck like the std oil from WP and feel a good replacement oil makes the fork perform better.I like silkolene and Motul and putoline oils.