Leaky USD Fork Seals

[RJ]

I recently went through a major hassle of changing out a fork seal on my USD forks. Much to my chagrin 3 months later the same fork was leaking again. I found a tip on gixxer.com that seems to have worked: Pry off the dust seal. Then take an old photo negative and work it up between the fork tube and seal lip. Move it around in a short sawing motion. If the leak is caused by a dried up bug guts or loose road dust the film will pull it away from the sealing surfaces without damaging the seal. It worked on my bike. I might have even been able to avoid the seal replacement exercise 3 months before. Be aware that when you do push the negative into the seal area it will leak out some oil but that will stop once you pull it back out.

[Billy Ricks]

I recently went through a major hassle of changing out a fork seal on my USD forks. Much to my chagrin 3 months later the same fork was leaking again. I found a tip on gixxer.com that seems to have worked: Pry off the dust seal. Then take an old photo negative and work it up between the fork tube and seal lip. Move it around in a short sawing motion. If the leak is caused by a dried up bug guts or loose road dust the film will pull it away from the sealing surfaces without damaging the seal. It worked on my bike. I might have even been able to avoid the seal replacement exercise 3 months before. Be aware that when you do push the negative into the seal area it will leak out some oil but that will stop once you pull it back out.

I've seen that tip somewhere before, probably the Gixxer site. I need to give it a try on the '86 I picked up earlier this summer.

[bwringer]

Cleaning the seals like this is a common task on dirtbikes, and you can even buy a special little plastic thingy for this purpose.

[kichigai]

Motion Pro Seal Mate

RJ,
Here you go! The plastic thingy!!!

This tool is made by Motion Pro called the Seal Mate

http://www.cyclegear.com/spgm.cfm?L1=&L2=&L3=&L4=&item=TUC_15-8356&tier2=12

[RJ]

Yeah I guess that's the proper tool for such an issue. I never really had to worry about cleaning leaky fork seals before on telescopic forks. If they leaked they got replaced. These USD forks have really thin oil in them and have gravity pulling the oil down as well. I would imagine that makes them more prone to leaking.

[kichigai]

RJ,
What year and bike size fork did you use??

[RJ]

'95 gsxr 1100.

[kichigai]

RJ,
I was asking because I have a set of seals and dust covers for a 95 GSXR 750 USD fork which I bought by mistake. My forks are from a 93 GSXR 750 which I found are a bit narrower.

[RJ]

Yeah they wouldn't fit, but thanks for the offer.

[80GS750]

im assuming USD is UpSideDown.....

[RJ]

USD = upside down. Much improved design over older telescopic forks. Almost all of the Jap and Euro high performance bikes run them.