HOW DO I CHANGE THE FORK SEALS ON MY 1983 HONDA VT500C

SOURCE: Need to change fork seals on xr400

http://www.carlsalter.com/motorcycle-manuals.asp

free pdf service manual here

SOURCE: CBX Restoration

I have 4 CBX's '79-2, '81 Turbo, & '82. If you are using stock forks and not a real agressive rider, the ATF fluid works just fine. If you are using performance forks, have other internal modifications, or prefer the twisties, you can experiment with different weight oils. I believe that ATF is about 10W ...

SOURCE: 99 CBR 900 Front fork seals

If the seal has been cracked by the cold weather it should be replaced. For someone mechanicly inclined and with the proper tools this is not a hard job. For the novice it can be one of those times you could have sent it to the shop and spent less time and money, and gotten better results....
As to a seal conditioner, the seals today are generally made of synthetic material. No "conditioner" will work. If the seal is made of rubber you have a 90% chance that a product called 'MARVEL MYSTERY OIL' will solve the problem. This prouduct was created in 1917 and marketed in 1923. Google the product name for more hystory and uses today. Basicly, the oil causes rubber to swell. This tightens seals and thus fixes the problem. Most any good auto parts store has this stuff on the shelf. By the way, if the bike was purchased new, wouldn't this be a warranty repair?

SOURCE: front fork leaking oil from bottom of the seal.

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

SOURCE: How do I change the fork seals on a 2008 Honda CRF

hi,replacing the seal is quite easy,although it will sound complicated,jack up or lift the bike off the ground so that the front wheel is in the air(about 12-14 inches should be enough,remove the front wheel from the bike,remove each fork leg,this is done by undoing the bolts(4 on each leg)the front fork is quite easy to work on just do one at a time,remove the dust cover from the top of the staunchion tube(larger diameter tube),beneath that dust cover you should see a retaining clip that holds the seal in place,remove the retaining clip(and dont lose it),the seal is now ready to remove,the easiest way that i know to do this is to force a screwdriver through the body of the seal,you may need to hit the screwdriver with a hammer as some seal have a tin backing plate,put a hole through the seal on each side of the fork leg taking care not to damage the chrome of the fork leg,then use the screwdriver to lever the seal out of the fork leg,to reinstall the new seal,put a smear of grease or oil around the outside of the new seal,slide the new seal down the fork leg and seat it squarely into the fork tube,very carefully tap the new seal into place being very carefull not to damage the outer surface,i use a small piece of dowell type timber to do this as the wood doesnt damage the seal surface,i use a small ballpeen hammer to tap the wooden dowell,once you have the seal seated down the tube you should be able to see the groove for the retaining clip,reinstall the retaining clip making sure it is seated corectly,replace the dust cover,if you are going to replce the fork oil or top it up do this once the fork leg is back in the bike,repeat the whole procedure for the other fork leg,once you have done the fork seals reinslall the fork legs back into the bike and refit the front wheel,to top up the oil in each leg,simply undo the large cap on the end of the fork leg,you may have to remove the handlebars to do this,be carefull as the cap will be spring loaded and can easily fly off if you are not ready for it,top up or fill with the correct weight oil for your bike(normally a 10w oil),check with your local honda agent for the correct quantity,normally between 400-500 mls,this all sounds quite complicated but is actually quite easy and can be done with a minimal of tools,each fork shold take about 1/2 hr to do...hope this is a help to you