Question about fork seal failure

[skyway]

I was wondering what the symptoms are of a blown fork seal that has leaked out a bunch of fluid out of only one fork leg?

I have never experienced what it does to the handling and would like to know in advance JIC.

 

[twowheelnut]

I would think that you'd get a lot of wallowing in the corners... but, you'd prolly see the leaking fluid, toot sweet. I don't think you'd lose a bunch of fluid all in one shot, though.

Blowing seals... A topic, I'm sure, skooter will chime in on.

 

[smitty141]

Most of the time, if you catch it early you can just clean the seal. I have done this for years on my dirt bikes, and also works on the street. Take a small screw driver and pry the dust seal up. Then take a NEW business card and slip it around the slider(tube). You should be able to slip it between the seal and the fork tube. Just work it around the tube, some oil may come out. Be carefull not to leave a piece of the card in between. A new card works best, most of the time it is just dirt that causes the leak. Hope this helps Sky... Smitty

 

[FlyingLow]

Okay, that's an interesting new trick, and worth a try. I was just gonna say, replace the seal.

According to the manual, each fork holds 22.3 oz of oil. Maybe 1 ounce of oil running down your slider will be a humongous mess, but not affect handling with 21.3 ounces still inside.

If it's leaking, it's leaking. Just replace the seal and be done with it.

 

[Toecutter]

Then take a NEW business card and slip it around the slider(tube). You should be able to slip it between the seal and the fork tube. Just work it around the tube, some oil may come out. Be carefull not to leave a piece of the card in between.

I heard of this method using some shim stock, but I'd probably try a feeler gauge myself.

Whatever you do, don't take it to Gary's in Fresno for seal replacement. Bad things man, bad things....

 

[evil_henchman]

I didn't notice any handling differences as far as shock performence when mine blew. Braking was a different story, pads don't like fork fluid.

 

[smitty141]

Okay, that's an interesting new trick, and worth a try. I was just gonna say, replace the seal.According to the manual, each fork holds 22.3 oz of oil. Maybe 1 ounce of oil running down your slider will be a humongous mess, but not affect handling with 21.3 ounces still inside.

If it's leaking, it's leaking. Just replace the seal and be done with it.

I have used the card trick for years, and works most of the time. Dirt is the main problem with fork seals.

The manual shows the volume in each fork. This is more or less a guide line, the air gap is the bottom line. When you change your fork oil always fill the fork above the damper/ cartridge rod for proper bleeding. With fork tube all the way down you pump the rod to remove any trapped air in the fork. The last thing is you pull the tube/slider/outer tube all the way up,(this dumps any oil trap between the slider and the lower leg to the inside). Then with the fork collapsed with the damper/cartridge rod down you remove the extra oil to the proper level.. 100mm I believe is the stock air gap... The air gap can be a little more or less, this controls the last few inches of travel. So if you are bottoming the front alot make the air space smaller(more oil), if you don't use all the travel, less oil is needed. There are standards to the short and long side of the air gap(space). There is nothing wrong with bottoming now and then, you just don't want it happening all the time. Smitty

 

[evil_henchman]

I have used the card trick for years, and works most of the time. Dirt is the main problem with fork seals.

Just remember, some people just have to have a gadget for everything:

Seal Mate

Any piece of plastic film with the consistancy of 35mm photo film or tear away goggle lens covers will work as well.

 

[Rickster]

Then take a NEW business card and slip it around the slider(tube). You should be able to slip it between the seal and the fork tube. Just work it around the tube, some oil may come out. Be carefull not to leave a piece of the card in between.

I heard of this method using some shim stock, but I'd probably try a feeler gauge myself.

Whatever you do, don't take it to Gary's in Fresno for seal replacement. Bad things man, bad things....

Caution using the feeler gauge -- may damage the seal (if it's the metal type of feeler gauge), and may just push the dirt around the seal -- the card may be better.

 

[OrangevaleFJR]

I changed the fork seals a couple times on my 77 BMW. Wish I knew the card trick back then!

Anyway, the symptoms of leaking oil was a really messy front end of the fairing and back half of the front fender.

Cleans up easily enough though

But when I was lazy enough to let it go for quite some time before I repaired it, here are the ride syptoms:

1) on slow speed bumps, you'll notice the fork pulling hard to the side of the softer fork

2) on high speed turns, you notice you're riding a bit lower and on bumps in turns, there are some wallowing characteristics, but really not as bad as you'd think

It was never bad enough to cause an accident :clapping: