MRKRacing125

Member
Oct 24, 2000
507
0
I havent done anything to my forks, but turn the comp. and rebound on them. Anyways, I think I am going to lower the fork oil in the forks to make them alittle less stiff for a 125LB rider:) How do I know how much to put in? Is there anyway of measuring without having to have like a fork oil height ruler? I much of the oil should I leave in the forks? 2001 yz125. MX riding. I will be replacing the fork oil so thats not a problem.
 

Zenith

Member
Jan 11, 2001
483
0
I just use a standard ruler. Dry it and stick it into the fork until say 150mm on the ruler is at the top of the fork tube, then take it out quickly and see where the oil came to on the ruler just like an oil dip-stick in a car! Subtract the number on the ruler from 150 and voila! Obviously this means adding and pouring out oil for a while to get the right level but you get used to it after a while.
I'm not sure but I thought changing the oil height will just affect the stiffness just before bottoming...
 

eunos

Member
Jan 17, 2002
61
0
Use a plastic tube with a piece of tape on it, lower it into the fork leg and either use a plastic hypodermic or suck (dont swallow) when no more comes up the pipe oil levels correct. Dont know measurement for your bike (try dealer) 426 is 130mm. The oil only affects the last 4 inches of travel and level can be increased in 5mm increments to prevent bottoming.
 

slideways11

Sponsoring Member
Apr 18, 2000
411
0
I use a syringe with a piece of plastic tubing on it cut to the exact level I want the oil level in the fork to be. I run both my YZ's at 100mm. I use Mobil1 ATF (syn).
 

MX823

Member
Nov 8, 2001
77
0
The Yamaha mannual does a great job describing the fork seal removal and installation process in great detail.

I would reccomend an oil HT of 100 or 95 mm [measured from top of fork tube down to oil]. If you want a cheap inxepensive fork oil level, mark off a turkey baster with MM in incriments of 5......


And typically only the last 1/3 of the travel is affected by oil HT ,

other things to consider, oil weight [rebound damping affected as well ], springs,
 
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