Showa 447 fork seals and dust cover replacement on a 1981 Honda CM400T

My first attempt at replacing the fork oil seals, new fork oil and new dust covers was a success. With the help of my pdf manuals, videos on youtube and any other web search helped to cause more confusion after I got the forks apart because I didn't seem to have as many gaskets or other parts for the inner workings of motorcycle forks.

Having disassembled my forks, removed the oil seals, replaced them, added new fork oil and seals. This is what I can share to get you started on your venture for replacing your gaskets and fork oil on this model, Showa 447.

Tools I used were a 19mm, 17mm, 14mm, 12mm and two 10mm wrenches. The two 10mm wrenches were needed at the top fork clamp bolt because the other side of the bolt would spin, and you need something to hold it on that side too. The last two tools I used were a 6mm allen wrench to loosen the upper and lower fork tubes at the base of each fork and a Philips screw driver to release the speedo cable as it will help in removing the front tire. I have crash bars on my motorcycle so it was an easy solution to raise the front end by safely placing the jack under that bar with the center stand down and raising the bike until the rear tire was on the ground.

One of the main indications this needs to be done to your forks is streaking oil on the upper tube. Not only does the dust cover need to be replaced, the inner oil seal needs to be extracted, replaced, new oil added then reassemble your fork tube.

Fortunately, when you are working on this project, it's pretty straight forward to remove the forks. Take steps to remove the front wheel, it will only be in the way if you leave it in place. Once removed, loosen the 4 bolts that hold the fender to the Right and Left fork assembly. Two bolts at the top of the forks, two bolts behind the front emblem. Your forks should now be reasonably loose enough to slip out.

I can save you time by not loosening the turn signal bolt. As it appears to be attached to the upper fork tube it is indeed hollow and your forks will slip out of this tube.

At this point I had to take two screws out of the head light to reassemble

We'll get to the larger fork cap bolt later, loosen the 10mm fork bolt

Remove this cover to reveal two 12mm bolts.

These two bolts are only on the right side

These parts totaled 20.00 from mrssuperdeals on Ebay. I would have been charged 80.00 to have this done.

Fork removed.

At this point there are few pictures left. I found that once the 6mm bolt was loose and the fork tubes came apart, it did not extract the inner oil seal like I have seen done on youtube videos. I had to pry it out with a flat screw driver. I am sure there is a tool available to make this more fun, so I took care in extracting it as to not score the surfaces that keep the oil from getting past the new seal.

To replace the new oil seal I used a large socket. It wasn't as big as the oil seal so I just moved it around the seal as I seated it. Make sure it goes far enough to place the retaining spring.

This what the upper tube looks like. The bolt and spring slide down the tube and the bullet goes over it on the other end. Take care with proper orientation when reassembling.

What my manual did provide was 6.4oz of fork oil per tube. Instead of just trusting that, I wondered if it would be right and found a pretty cool method as to why it's 6.4oz. After I filled the fork and replaced the spring, I pulled the upper tube down to compress it all the way, this is without the cap in place.

6.4oz for my fork tube showed it filled in the upper fork tube with the tube completely compressed.

I pulled the upper tube back up, put the fork cap on, fork oil seal spring in place, dust cover and reassembled both forks.