Fork oil has leaked after compression. Do I need to replace the seal or just top up the oil?

Start off by removing the forks from the bike, then remove the top caps (bolts) from the forks. Once removed take out the spacer and fork springs from the forks. Tip them upside down to get the fork oil out. Now with the forks empty from fluid and springs you will compress the forks all the way to make them as short as possible. You will need a fork dampening tool or a air gun to split the forks by removing the bolt inside the fork tubes. Once this is achieved you can pull the forks apart and replace the fork seals. When putting fork oil back into the forks if you are not sure how much to put back in, just compress the forks all the way down and fill each leg 6 inches from the top. That amount works for just about any motorcycle with conventional forks. Use 10 w fork oil.

G'day. A couple of suggestions-
Damage to the fork slider-chips or dings.
Too much oil in the fork on re-assembly can cause the seal to go.
Worn or loose fork bushes will flog the seal prematurely.
When you transport the bike-if you don't use a seal saver can pop the seals.

So let me help with these.

Be sure that the fork slider is not scored,dinged or damaged on th surface.

A good double check of the oil quantity is to ensure that when you have re-filled the tube with oil & primed it(worked the air out of it), the oil level should be 100 to 110 mm from the top of the leg to the oil with the fork fully compressed. If the level is less than this-drop it to 100mm.

To check the fork bushes-try pull on the front forks front to back(wobble) & feel for looseness in the bushes.

And finally-When you transport the bike-put a chock(I use an empty 5ltr oil container-but you can buy propper chocks from the bike shop) in-between the forks at top of the front wheel .
Now when you pull the front end down it will stop on the chock & stop the front forks being under excessive compression for extended periods-so it saves the fork springs from sacking out too.
I hope this proves helpfull.
Kind regards Andrew Porrelli

You need prop the bike up on front and rear stands. The fron stand needs to be the type that holds the bike up by the headtube. Remove brake calipers, front wheel, fender. Then loosen the upper and lower triple clamps. Loosen the clip ons. But before loosening the lower triple, loosen the fork tube top caps.

Drop out the legs. take off the top caps, pour out the oild, and compress the spring. I'd use a fork compressor, race tech makes a nice one. Loosen the top cap from the damping rod. Remove the top cap then pump out the rest of the oil from the damper.

Next, remove the outer dust seal. Remove circlip. Then you need to just extend the fork several times quickly to "bang" out the oil seal and bushings.

The outer bushings, if they look good, need to be gently pryed off using a thin flat head screw driver in the **** of the bushing. Same with the inner bushing. Now the oil seal, metal washer and circlip all come out together. Remember the order.

Lube up the new seals with fresh oil. put back on the fork lowers in the same order they were taken off. Replace bushings at the same time if there's any brass showing. I usually do it any way since the seals seem to go at the same rate as the bushings for me.

Once back together, seat the seals. There's a tool for this, but I usually **** the old oil seal so I can get it on the lower fork tube between the new oil seal and new dust seal. and I quickly compress (bang) the fork a few times until the groove on the upper leg is showing so the circlip will lock back on. Probably not recommended but I haven't ruined a dust seal in about 20 years now.

Fill fork with proper oil viscosity and volume (don't remember how much or weight for zx7s). cycle the damper about 20 times to make sure they're full of oil too. insert spring, re-compress, lock on top cap to damping rod. screw on top cap. reassemble fork on bike. Remember to torque the top cap with the top triple clamp loose otherwise the caps can bind.

There is a seal in the "slider" of the front fork, the part that moves up and down. I haven't had a chance to work on the later forks but the earlier 41mm forks are quite simple.

Start by taking the drain plug out of the bottom of the slider and work the slider up and down to blow out all the oil. Then, remove the front wheel. Remove the top cap from the upper tube and loosen the top plug. Now, with the top plug loose, loosen the pinch bolts and slide the fork out of the triple trees. Remove the top plug carefully, There is a BIG spring in there. Once you have the plug out lift the spring out and set it asside. Notice the tapered end of the spring. It goes back in first. Turn fork tube upside down and allow as much oil to drain out as possible.

Now, look at the bottom of the slider where the axle goes. Up in a hole there is an allen head bolt. it is designed to use a special wrench but a regular 8mm allen key in GOOD shape will take the bolt out. It's best to use an air wrench to do this with. With the bolt out, the slider should slide right off.

Down inside the top part of the slider is where the seal is. Theres a snap ring, a spacer, and a seal. Replace the seal and put a little oil on it to assist reassembly. Put everything thing back together and add the appropiate about of oil. Since your forks are much larger than mine, I have no specs as to the quantity. The owners manual should tell you or a call to a local Harley dealer. Sorry but thats a good as I can do. There is a "wet" measurement and a "dry" measurement. Since you disassembled your fork, use the "dry" quantity of oil

it s something you can do yourself if you're mechanically inclined and pay attention to detail. there are some special tools you need, such as a fork spring compressor, fork seal driver, and snap ring pliers if you don't have any. the internal parts in the fork must go in the same way they came out, and all parts should be cleaned prior to reassembly. you should also consider replacing the bushings along with the fork seals and dust covers. might really want to consider letting a professional do it so that way the forks still don't leak after you put in the new parts.

Each fork has an outer dust seal, and an inner seal inside of that. Dirt gets between the seal lip and the fork slider and causes the oil to escape. The fix is to have them (Both sides) replaced. You need a fork seal driver tool (Size specific for the size of the fork) and something to measure out the oil amount. It's not an easy job, if you have never done it. Also... if the oil has never been changed, it's due.

check first to see if the leaking fork has any rust pitting on the chrome,if it has and its a very small blemish then fettle it off first,and just replace the leaking seal,as the saying goes..if it aint broke dont fix it,if the seals had been in the forks for years and the bike not used then consider replacing both..

change the oil seals and oil in the fork,and avoid wheelies on the bike and off road biking 

Yep, drain the fork oil, raise the front wheel in the air, remove the front wheel and axle. The nut to remove the lower leg is at the bottom, hidden by the axle. If it still leaks after seal replacement your fork tubes and lower leg sliders are worn out. Reassemble and remove the top fork cap. Pour in the correct cc of fork oil and ride.

If you get the sevice manual or contact a dealer to get the correct oil amount for your bike, they need to know the model and year, you have to have the forks off the bike. take the fork caps off, take the springs out compress the upper fork tube all the way and add the specified oil. if they also give you the measured amount from the top that's the best way to get both fork oil levels exact. there is a special tool that you set the oil level in millimeters and it sucks out the oil to the right level, but before you do that step after adding the oil always pull and push on the cartage rod several times to remove air from the cartage tube. you will hear the air coming out and you will feel the changes in the cartage rod as the cartage tube fills up with oil and the air is removed.
something i'm confussed on though is if you replaced a seal you would have had to brake down the fork to replace it. you would have poored the oil into a container, cleaned all the internal parts,and used a fork seal driver to install the new seal. part of your question asks where do i put the oil in? thats in the open end of the fork after you have taken off the fork cap. It sounds to me like you only replaced the dust seal on one fork. that is not going to fix your leaking fork. you need to replace the oil seal thats pressed inside of the top fork tube.