Honda with a leaky fork seal Hack?

VintageMBike

Been Around the Block
1982 Honda CB900F.

Noticed a leak on the seal. Bike feels unbalanced and when riding I looked down at the seal and saw a teardrop worth of oil on the fork tube, but also saw where oil had run down and I missed it.

Some say to use camera film to get out the dirt like in the video below. Has anyone tried this? Im hoping I dont have to replace the seal, just concerned that that much oil leaking out may not be caused by debris between the seal and the fork, but I know little of these things.

Skip to 1:22 because this guy talks too much:

https://www.youtube.com/watch?v=Pv5VSMP0Usc
 
Yes. Sometimes it works, sometimes it doesn't. Trim it so it has sort of a loop/hook shape at one end. The idea is that you want the film to pull the dirt and grit out of the seal. This only works if the seal rubber is still good. If the seal rubber has shrunk or hardened, it will not work. Motion Pro actually makes a tool called a Sealmate that does this very thing. You can cut it to be shaped the same.

mot_10_sea_mat_for_sea_cle.jpg
 
irk miller said:
Yes. Sometimes it works, sometimes it doesn't. Trim it so it has sort of a loop/hook shape at one end. The idea is that you want the film to pull the dirt and grit out of the seal. This only works if the seal rubber is still good. If the seal rubber has shrunk or hardened, it will not work. Motion Pro actually makes a tool called a Sealmate that does this very thing. You can cut it to be shaped the same.

mot_10_sea_mat_for_sea_cle.jpg

35mm film broke so I used a NYC Metrocard and voila, no more leak! Seals were nice and soft. Now to add oil!!!
 
The Jimbonaut said:
Nice trick - I had no idea

Yeah I was in the dark about it until yesterday but its WILDLY popular. Even Revzilla has a column about it:

https://www.revzilla.com/common-tread/this-tip-could-save-you-a-fork-seal-replacement-job

"
This tip could save you a fork seal replacement job
Lemmy Dec 03, 2015 16 Comments
I am becoming antiquated, like a 35 mm camera.

That is a great irony, because the tip I’m about to share is actually becoming more relevant on modern motorcycles, and uses a staple of the 35 mm camera world: film. Remember that stuff?

I was standing around the water cooler with a colleague who was suffering a leaky fork seal, and I asked if he tried the film trick. All I got was a blank stare, so I explained it to him. Later, back at my desk, I asked our lead video editor if he knew what the hell I was talking about. He’s a few years younger than I am, but he used to ride dirt, and I thought all dirt riders did this. Another glazed look.

So let me get to the meat and potatoes of what I am yammering on about: If you are suffering a leaky fork seal, the fix is usually a new seal. Seals are cheap, but as anyone who’s performed the task can tell you, the job is kind of a pain in the ass. Before you start ripping stuff apart willy-nilly, try this easier way to get the oil to stay inside the fork tubes.

Sometimes, crap becomes lodged between the seal lip and the fork slider. (That’s why this tip used to be common knowledge among dirt riders.) Often, dislodging whatever detritus is trapped between the rubber seal and the fork tube is enough to allow the seal to once again lie against the inner slider. Abracadabra, good as new!


First, get the gaiters off if you have them.
It’s easy to do. Cut off a chunk of 35mm film. Pop your dust boot up. Gently slide the film between the seal and the fork tube. Work it around the seal, up and down, until you get back to where you started. Done.


Then pry up the dust seals carefully.
What if, for obvious reasons, you don't have any film handy? I’ve used feeler gauges, plastic, and even a business card to do this on the road. If you can use something softer than the sealing material, that’s the way to go. Using something like a feeler gauge increases the chances of tearing the delicate seal material, but sometimes you gotta do what you gotta do.


Slide the film between the oil seal and the stanchion. Work it gently around the circumference of the seal, and odds are excellent that any debris that's been allowing fluid to pass will be displaced.
Remember how I said this trick is more relevant now than ever before? That's because many modern forks are upside-down. Because of that, the reservoir holding the fork oil is entirely above the seal, rather than below it as in a conventional setup. What that means is that a) gravity is helping your leak move faster, even when the bike is parked and b) it’s more likely to contaminate your brake pads. Just when DSLRs are at their cheapest. Rats.

Some of you probably already knew this little procedure. If I saved the rest of you an unnecessary teardown, you're welcome."
 
Well I'll be dipped in shit. That is possibly the greatest thing I've learnt today.
 
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