The film trick

Film used to repair leaking fork seal” width=

A piece of film can be used to repair a leaking fork seal.

I replaced the fork oil and upgraded to progressive springs on my Magna back in April. I no sooner finished that project when I noticed a leaking fork seal in my Valkyrie. I really didn’t have time to do it myself, so I got a quote on having it done. It was only about $100 in parts, but the labor was going to run close to $400. OK, so I do have time to do it myself.
Researching the procedure, I quickly realized why the labor was so expensive. This is not a simple repair. It requires a couple of special tools and, if done incorrectly, can damage the replacement parts. In other words, you can waste $100 in parts, and whatever your time is worth, and accomplish nothing. So I kept riding with a slowly leaking seal.
I hadn’t noticed any performance degradation yet. I knew eventually I’d have to tackle this problem, but I was hoping to put it off until winter. The Magna, with its upgraded progressive fork springs, was again out of action because of an ailing carburetor. If I tore into the Valkyrie, I’d have no bike to ride. So I wanted to get the Magna running before I pulled the front end off the Valkyrie. But there are just too many projects lined up in front of the carb job, so I just keep riding and watching the oil spot where I park the bike get bigger and bigger.
I found a wrench session about 5 hours away where they were doing fork seals on a Magna. One of the participants has experience replacing Valkyrie fork seals. He even has the special tools we need. He invited me to come up. But there was no way I could leave town that weekend, so I thanked them and suggested I might try to get up there later in the year.
In the meantime, however, somebody on the discussion thread mentioned the “film trick.”
I’d never heard of this, but apparently it is common practice among the riders of dirt bikes. It seems that leaking fork seals are part of off-road riding from debris working its way in between the fork tube and seal. Rather than replace the seals every time they see a leak, dirt bikers will take a piece of film, like used in old- fashioned cameras, and use it to try and clear the foreign material. They simply remove the dust cap, then cut a slight point on a strip of film. Then they slide the film up the fork tube, in between the tube and the seal. Then they push the film all they way around the tube, with the film at an angle. Very often this forces the contaminant out of the seal. You then wipe the oil off the tube and bounce the forks to reset the seal. You may have to repeat the bouncing and wiping several time until the seal reseats and you no longer see oil on the fork tube. But once that happens, you’ve just saved yourself a $500 repair.
So Sunday morning, I found myself kneeling at my Valkyrie’s front wheel, film in hand but no real hope in my heart. This just seemed to be too good to be true. A chrome shield that is supposed to protect the tube was in the way. But I eventually got the dust cap off and the film in between the tube and seal. Again, the shield made a complete 360-degree circumnavigation of the tube difficult, but I eventually succeeded. I looked to see if I could spot any material dislodged by my effort. I didn’t see anything. I wasn’t surprised, figuring there was little chance of this simple solution actually working. But as I began to wipe down and bounce the forks, I noticed that the seal had stopped leaking. As of Tuesday morning, the tube is still clean, and the oil spot on my sidewalk has stopped growing.
I’ve watched a lot of high-dollar, special-effect movies. I watched blue humanoids ride flying dragons, and a man in an iron suit fly. But stopping a leaking seal has got to be my favorite film trick.

- Guy Wheatley

Leave a Comment

Please note: Comment moderation is enabled and may delay your comment. There is no need to resubmit your comment.