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Fork seal life

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OK, don't know if this has been discussed before on this forum however they beat it to death on some of the others. I'd like to get a final "answer" if possible from the experts.

What is more likely to kill the life of a fork seal first.....

1) Being tied down in the bed of a truck for several to many hours (sitting over night or long drive time). Note; forks are stationary, no pumping going on.

2) Riding the bike for extended minutes (motos) to hours (off roading). Note; foks are constantly pumping up and down working the seals non-stop)

I know I didn't have to tell you those facts however for the lesser trained on the matter!

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From my experience, and everything I hear, strapping bikes down doesn't hurt seals at all.

I have a few friends who 24/7 leave their bikes in their trucks strapped down tight, and they also get years and years of live out of forks seals.

IMO, dirt is a big cause of fork seals leaking, and worn bushings. 👍

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From my experience, and everything I hear, strapping bikes down doesn't hurt seals at all.

I have a few friends who 24/7 leave their bikes in their trucks strapped down tight, and they also get years and years of live out of forks seals.

IMO, dirt is a big cause of fork seals leaking, and worn bushings. 👍

And you only get dirt and worn out bushings when it's ridden...Thank you.🤣

Experts...(not that you're not an expert Towliee) any input?

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mud and bad bushes, sitting for years not being used dries them out.Its mostly dings on tubes that does them in.

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and they also get years and years of live out of forks seals.

I feel fortunate to get months and months out of my seals. For me they last a while then one unexpected down poor at the track turning all the clay into peanut butter does them in every time.👍

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I feel fortunate to get months and months out of my seals. For me they last a while then one unexpected down poor at the track turning all the clay into peanut butter does them in every time.👍

You might try running seal savers or some type of protection like that.

Most my experience with fork seals, is with street bikes.. But me and my friends also slam wheelies down HARD very often, which street bike forks seals aren't made for. And really, I don't see fork seals blow out any more often on bikes me and my friends wheelie on, compared to people who ride normally.. Also me and my friends who wheelie, strap our bikes down very often, and my friend leaves his strapped down every day all day and only pulls it out to ride or work on it..

For the most part, almost every time fork seals blow out on a street bike I work on, it's due to worn bushings, so I always recommend street bikes to buy new bushings.

I have done a few different dirt bikes, half of them the bushings looked perfect, the other half I assume blew due to dirt.

Only dirt bike I have is a 2005 150f, and it comes with stock rubber covers over the forks, and I only pull the covers off every 6 months or so and they are always 100% clean inside. I think there is a chance my seals would have blown by now if it wasn't for my covers.

Basically what I'm saying is I don't think strapping down, or landing hard on jumps as 'much' to do with it. Mainly its dirt, or if the forks have a lot of hours on them, worn bushings. But of course nicks in the fork tube or bent tubes will also blow seals out repeatedly.

If its been more then a couple years since you replaced bushings, I'd go ahead and order them when you do seals just so you know they are good..

Also IMO, ALWAYS use OEM seals!

(I'm by no means an expert or pro, but I do all my own work, and I've done seals on many different bikes for people in my city. I've only ever had one set of forks leak, and that was using cheap seals I got off ebay, and I didn't replace the bushings.)

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You might try running seal savers or some type of protection like that.

Most my experience with fork seals, is with street bikes.. But me and my friends also slam wheelies down HARD very often, which street bike forks seals aren't made for. And really, I don't see fork seals blow out any more often on bikes me and my friends wheelie on, compared to people who ride normally.. Also me and my friends who wheelie, strap our bikes down very often, and my friend leaves his strapped down every day all day and only pulls it out to ride or work on it..

For the most part, almost every time fork seals blow out on a street bike I work on, it's due to worn bushings, so I always recommend street bikes to buy new bushings.

I have done a few different dirt bikes, half of them the bushings looked perfect, the other half I assume blew due to dirt.

Only dirt bike I have is a 2005 150f, and it comes with stock rubber covers over the forks, and I only pull the covers off every 6 months or so and they are always 100% clean inside. I think there is a chance my seals would have blown by now if it wasn't for my covers.

Basically what I'm saying is I don't think strapping down, or landing hard on jumps as 'much' to do with it. Mainly its dirt, or if the forks have a lot of hours on them, worn bushings. But of course nicks in the fork tube or bent tubes will also blow seals out repeatedly.

If its been more then a couple years since you replaced bushings, I'd go ahead and order them when you do seals just so you know they are good..

Also IMO, ALWAYS use OEM seals!

(I'm by no means an expert or pro, but I do all my own work, and I've done seals on many different bikes for people in my city. I've only ever had one set of forks leak, and that was using cheap seals I got off ebay, and I didn't replace the bushings.)

As mentioned in another post dried out seals from sitting makes a lot of sense too however I'm sure isn't the case with the guys suggesting "fork savers" (block between tire and fender) when tying down your bike. I just don't get it, I can almost bet that they don't even think that by riding the bike with dings/dents in the forks would cause seals to leak...because of the pressure the oil is under it wouldn't take much for a leak to appear. I think spending a few bucks on fork savers (plastic protectors for front of fork tubes) would be more beneficial.

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As mentioned in another post dried out seals from sitting makes a lot of sense too however I'm sure isn't the case with the guys suggesting "fork savers" (block between tire and fender) when tying down your bike. I just don't get it, I can almost bet that they don't even think that by riding the bike with dings/dents in the forks would cause seals to leak...because of the pressure the oil is under it wouldn't take much for a leak to appear. I think spending a few bucks on fork savers (plastic protectors for front of fork tubes) would be more beneficial.

+1 pm drying out seals, I also 'think' old seals will be more prone to blowing out, probably even more likely if the bike just sits without every being used for a long time. 👍

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The 'fork saver' spacer blocks' only real benefit is that they make the front end rigid, so that when you're hauling the bike and hit a pothole, the suspension won't compress and the tie down (momentarily gone slack) won't fall off.

Crap getting in the seals &/or seals drying out is what makes fork seals leak.

Sealsavers can help, but I've worn through a set in a single hare scramble (~3 hours). I don't think I've ever had fork seals long enough for them to dry out. For $25 a set, I just change them a few times a year when they start to weep (usually it's past due for a fluid change as well.)

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The 'fork saver' spacer blocks' only real benefit is that they make the front end rigid, so that when you're hauling the bike and hit a pothole, the suspension won't compress and the tie down (momentarily gone slack) won't fall off.

Crap getting in the seals &/or seals drying out is what makes fork seals leak.

Sealsavers can help, but I've worn through a set in a single hare scramble (~3 hours). I don't think I've ever had fork seals long enough for them to dry out. For $25 a set, I just change them a few times a year when they start to weep (usually it's past due for a fluid change as well.)

I agree with you on the fork "block" however there are those guys on the dirt bike forum section that insist they also save your seals...My view, the forks aren't constantly working therefore the seal's ok. It's the constant up and down motion that works the seal especially if the tubes are damaged or seal is dry, etc.

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My fork seals were rebuilt before I bought the bike, they looked like they were as they were very clean and no oil was leaking at all.

I started to get a right fork leak just 2 weeks ago and went out to buy the seals to do it myself.

In my personal opinion I think that fork seal life is severely degraded from the following things;

-Dried on mud in which the fork seal tries to wipe off

and the biggest

-Worn bushings in combination with tying down a bike without bleeding the air.

The inner and outer bushings have a coating of teflon that helps with wear and resistance for the part that it rubs up against. In the case of the outer bushing which is pressed into the outer tube, the inside of this bushing IMO experiences the most wear and rubs along the inner fork tube whenever you ride.

Bits of teflon flake off when a bushing is worn, and you literally get flakes of teflon in your fork oil and in the case of single chamber forks it can get into your valving and seals. For the case of dual chamber forks the seal is the only risk. These bits of teflon settle to the bottom of the shock where the seal sits and hard riding or tying the bike down tight without relieving pressure can help the bits into the seals.

When you truck is moving, even if the bike is tied down tight, the forks are still moving when you go over bumps etc, with the extra pressure it makes the oil want to push out the seal even more. If there is teflon bits floating around they will get stuck in the seal and you start to see leakage.

I'm pretty sure this is what happened to mine, the seals were replaced but the bushings were not.

Moral of the story, again IMO, is when you tie down your bike in the truck, release the pressure by unscrewing the vent screws on top of your forks. When you get to your destination unscrew the screws again and then release the tie downs allowing the proper air to get in there instead of a vacuum if you did not.

If your going to replace your seals and cheap out by not getting inner and outter bushings, then don't come crying on the forum about how shitty your manufacturers seals are cause they're leaking after 20 hours.

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I agree with you on the fork "block" however there are those guys on the dirt bike forum section that insist they also save your seals...My view, the forks aren't constantly working therefore the seal's ok. It's the constant up and down motion that works the seal especially if the tubes are damaged or seal is dry, etc.

When the bike is strapped down and the temperature increases outside the pressure in the forks increase. Same as when riding, the forks are worked and pressure builds in them from the heat of them being worked.

I had a friend's dad put new seals in a bike I just bought and he told me I should especially bleed the air out of the forks after riding and use a fork saver since they were new.

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I have had good luck by using a very thin piece of plastic to wipe the seal face between the seal and tube. Most of the time it's a very small piece of dirt stuck in the seal causing it to leak.

Also my suspension tuner told me to drop the dust covers down and clean the crap out between the seal and dust cover and then put some grease on the backside of the dust wiper. You will be surprised how much dirt will be in the grease the next time you clean them.

Clean off the dried on mud from the fork tubes between rides also.

Good Luck!

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I've only ever had seals leak after a sandy or muddy race. I didn't do a calculation, but compressing the forks can't cause much more of a pressure differential than naturally occurs during temperature changes.

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Well here's my 2 cents, I used to leave my bikes strapped down in the trailer loading the forks constantly. Within a couple months both bikes had leaking sealsthat had to be replaced, that was a year ago. I bought a couple blocks and have never had any more seals go bad. Just my experience not set in stone but it's kida a cheap insurance policy and does also stabilize them.

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I've only ever had seals leak after a sandy or muddy race. I didn't do a calculation, but compressing the forks can't cause much more of a pressure differential than naturally occurs during temperature changes.

👍 except for the bike I currently own (1994 Husky 610) none of the others "ever" lost a fork seal...granted I didn't ride all year however I did tie it down in the back fo the truck for long periods of time.

I still think it's the use from riding along with dried on mud that causes seals to leak...

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worst on them: mud and extended periods of sitting(months or years)

Thats taking into account the fork tube/mechanicals are not damaged and installed properly.

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Was told by a respected expert on this site that the most common reason seals fail is from pressure washing the bike and washing the oil film off the fork lowers. He said to always re oil the tubes with wd 40 or Tri Flow after washing and seal life will improve.

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How do you think the bikes get here from Japan, they are tied down with no slack in the suspension for months. That being said my seals blow ever 6 months.😏

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