Hi there,

I just got a new oil change for my both front fork because of broken oil seal.

So my question is, what is the standard weight of the oil that is on our stock bike. I use a MAXIMA weight 10 fork oil. Is this too heavy or too light? Please gave comment. And it is correct that I pour 400ml of oil into each fork? It is too much? Does anyone out there know the standard amount of oil to be fill in the fork(CLARK, BRYAN, MITCH....). Ps please gave me your answer in liters or ml as I did not take the height of the fork oil. :) lastly I found that my right fork rebound damping click to increase to a total of 30 instead of the original 20. IS the adjuster spoilt or I install it incorrectly? Please help me :D

I don't remember the exact volume of oil in each fork, certainly is about the 400 mark. The oil height must be measured as per the manual. The air spring effect is a very important part of your suspension, the part you rely on to prevent bottoming over really big jumps. I'm using about 90mm.

The WR forks appear to have the same damping as the YZ with lighter springs. The combination doesn't work well. The compression damping seems to come on too hard and gives a harsh reaction to small, sharp hits. The adjustment range in the compression is insufficient. I went down in oil weight to (eventually)2.5 wt, the lightest I could buy. This still required zero compression damping once the rebound was set. I'm currently using an oil of my own formulation that flows roughly twice as fast as 2.5wt. belray. With this I use a few clicks of compression and the harshness is less. I suspect that the size of the valve that preceeds the damping stack is too small, the gold valves seem to work on this assumption. It has to be something simple because there are plenty of cheaper forks that don't have the problem.

The oil is KYB (Kayaba) 01. This is 2.5 weight oil. Measured from the top of the fork leg, standard height is 145mm. The band is 80mm-150mm. Oil capacity is 563 cubic centimeters (563 milliliters).

Be sure you bleed the air out of your forks after riding. Any entrained air in the oil will stay there until you bleed it off.

[This message has been edited by Kevin in New Hampshire (edited 02-20-2000).]

The only fork oil I use is Pro Honda HP fork oil 5wt. This great stuff and used by many suspension shops.

You can get it at a Honda dealer. You should always set the oil level in each fork by totally filling it, pumping the fork rod/cartidge-getting all the air out, then topping it off a few more strokes on the rod then suck the oil out down to the level you want (ie 100mm, 125mm, etc.). I think the range is 145mm to 80mm.

There are several tools available to do this with or you can make one out of a turkey baster, a piece of fuel vent line and a straight small diameter tube. Put a small "O" ring on the straight tube and set the "O" ring at the mm measurment you want, connect the tube to the turkey baster via the vent line and suck out the fork oil down to the required level, as set by your 'O" ring.

Its important to do it this way as the air volume is critical in bottoming resistence and you want to know what the measurment is and that it is the same in each fork. 145mm is the least resistant to bottoming and 80mm provides the most resistence to bottoming. The amount of oil in the forks will slighly affect the rate of travel during the last 20-30% of the stroke.


Thanks for the great post (as well as others), Clark. This is exactly how I have done it on other bikes, and I use the some homemade tool. Kind of strange, huh. Am still waiting on my WR, so I haven't done the fork oil change yet, but there is something I want to add to Clark's wisdom:

When changing fluid, flush the old fluid out really well. Drain the old fluid while pumping it out. Fill it up and work the forks about 10 times. Drain well, fill, then measure. If you aren't in a frenzy, let it drain overnight upside down after the flush and before final filling.

Folks have had good luck with improved handling by raising the forks in the clamps 5-10mm. Remember to use a torque wrench on the clamp bolts to the proper specs-forks are outrageously expensive!

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