Fork Seal Excercise

[CptKirk]

Bought all the components to rebuild the forks on my 87 VR. Installed all new parts and reassembled the forks. All went well until I seated the seals. Found they would not drive in far enough to install both the top spacer (gold colored upper spacer) and the snap ring. No such luck as it appeared the seal wasn't bottomed out enough to allow both spacer and snap ring.Bought a seal driver and tried to get the seal to bottom. Thought they were hydro locked by grease lube. No such luck as the seal driver would not bottom out the seal, in fact it was telling me they were already bottomed. Finally decided the seal must be the issue so disassembled the forks to remove some grease. Found when I compared the old seal with the new ones that the new seals were thicker by exactly the thickness of the top spacer. Reassembled the forks and left out the top spacer and installed the snap ring. The forks are back together and hold air fine. Bottom line is to compare the seals before assembly. Wasted a lot of time but the fix was simple once I knew the problem. The snap ring above the seal is all that's needed to tightly retain the seal and top bushing, the top spacer takes up the slack with the thinner stock seal (lower spacer (silver) is in place). Anyone ever run into the same thing?

Edited September 6, 2008 by CptKirk

[cimmer]

Were these Yamaha OEM replacement seals or where they an aftermarket seal. Just curious as I am thinking about rebuilding my front forks also.

Thanks

Rick F.

[5bikes]

Eliminate the washer and expansion wave spring. Super glue new seals around the outside edge on top of the original seals. Glue the dust wiper on top of the new seal. Faster installation, lasts longer and only about 1/2" higher.

[CptKirk]

Super glue, hilarious but I like the look of about a quart of epoxy and fiberglass mesh. The seals were aftermarket bought on ebay. Just make sure you check them against what you take out. The forks seals have been holding air with no pressure loss (12 psi) for 72 hours.

Next time I'll use cutting torch to trim thm to size for a precision fit and shape the epoxy and fiberglass to make a cool air scoop. Will get a box for parts that I figure don't belong, after consultation of course.

Edited May 18, 2009 by CptKirk

[CptKirk]

The seals I was sent by the supplier held air pressure and oil for a short time making me think all was going to be fine. NOT, they leaked through the winter. This year I disassembled the forks and removed them. It would appear I was sent the wrong seals. In comparing them with the stock ones I found the ones I had installed were approx 1/8 " too deep and would not allow enough space for the top spacer. Bottom line is check the seals by compariosn. The new correct seals work perfectly and the top sapcer fits where it belongs along with the snap ring. Long story short never trust the parts you get and always compare them to the origionals. Learned my lesson but am sure good at taking the front end apart and reassembling.Apparently you can trust four people as long as three of them are dead.The top washer has to be in place or the seal has nothing to push against on the back stroke and will bypass oil.

Edited May 18, 2009 by CptKirk

[Pappa Bear]

I just replaced mine with aftermarket ones. The first were from Pyramid Parts, not the correct one they had no step down to them and would not seat far enough into the tubes for all the pieces that go on top to secure the retainer clip! The second set I got had the proper measurements to replace all parts perfectly ! I guess its buyer beware, :buttkick:But now I really know how to do seals and springs. I kinda would like to try it again against the clock to see how fast I could do it, Not hard at all

[CptKirk]

That's where I got the goofy seals from, Pyramid parts. Things that make you go hmmm.......... Guess that's the last time for them.They held oil and air for a short time then started weeping.

[GeorgeS]

I put in a set of aftermarket seals. One of them only lasted about 10K and went bad.

Not sure why.

 

I think next time I will just get them from Yamaha, might be worth the extra few bucks.