fork seals/oil

6 replies to this topic
  • strack

Posted April 21, 2002 - 10:15 AM


After riding this past weekend i decided its time to change my fork seals. Ive cleaned them a few times with a fealer guage but now they leak every ride. My question is, how hard is it to change the seals? do i need any special tools? also what kind of fork oil should i use, and where/how much should i add to it. Thanks for your help

  • skthom2320

Posted April 21, 2002 - 05:21 PM


You are asking questions that are in the factory service manual. Do you have it?

If you don't, you really DO need it to change the seals properly.

My advice is to get the factory manual, read up on the seal change, then do a search here on TT. There are several very good write ups on it -including motoman393's description of installation of race tech equipment. He has a nice description of what tools are required. The link is

The things you need are - 14mm hex socket to remove the base valve, a cartridge holder, and a seal driver. You can get the 14mm hex from a Napa , the cartridge holder and seal driver from Scotts (or you can make them - see motoman's web site).

[ April 21, 2002: Message edited by: skthom2320 ]

[ April 21, 2002: Message edited by: skthom2320 ]

  • strack

Posted April 21, 2002 - 06:15 PM


thanks for the input. I ordered the manual tonight, hopefully it will be here soon, this is the first major thing that ive had to do on this bike so far, and i dont want to mess is up just tearing in to it, after looking at all the tips i think i can do it fairly easily as long as i take my time. thanks again

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • RichB

Posted April 22, 2002 - 04:27 AM


Check you PMs.

  • skthom2320

Posted April 22, 2002 - 09:40 PM


I didn't answer your question about oil. You should have found a ton of advice in your search, but I used Enzo's KYB 01 oil with my stock boingers - much cheaper than the Yamaha 01!

I had my suspension done since then and now use Motorex 7.5 wt.

  • Rich_in_Orlando

Posted April 22, 2002 - 10:54 AM


You don't have to remove the base valve to replace your fork seals!

It's very simple: Take the forks off the bike. Use a 19 mm wrench to remove the cap bolt. Use a thin 17 mm wrench to remove the assembly that holds the spring in. Remove the spring and drain the oil out. Now flip the forks upside down and remove the snap ring with a little flat-bladed screwdriver. It should come out easily. Now pull the forks apart. They come apart easily, too. You should replace the oil seal, front fork piston and slide metal on each fork. The piston and slide metal are teflon-coated and that coating sometimes wears off. You might find that you don't need them, but if you do need them, you'll probably have to order them and then wait to put the forks back together. I'd rather have them and not need them than need them and not have them. All 3 parts (seal, piston, metal) should cost you about $30 for each side. Put it all back together in reverse order. I don't have a fork seal driver, so I just use a big, fat, flat bladed screwdriver. (That's certainly not the best method, but it worked.)

I use Bel-Ray 10 weight fork oil. Don't know if that's the best--I think they come stock with 5 weight oil.

  • bassr_#186

Posted April 24, 2002 - 08:32 AM


Regarding removal of the base valve, you might not have to remove it to replace the seals, but you should remove it so that it can be cleaned properly.

Related Content


Should I buy this bike? help....... by Numsa Hul

Dirt Bike   General Dirt Bike Forums   What bike should I buy?
  • * * * * *
  • 10 replies

Yamaha YZ450F 2017 by Chris.GVS

Yamaha YZ450F 2017
  • * * * * *
  • 1 review
  • Last review by Tommyk_55
  • On January 15, 2017

Megabomb Fitment by 288yz450

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • 1 reply

Chubby dad, looking at bikes , First trip to the orange/black forum ! by Slow_ride

Dirt Bike   Make / Model Specific   KTM   250-530 EXC/MXC/SXC/XC-W/XCR-W (4-Strokes)
  • Hot  28 replies

BIGBORE FOR YZ450F 2006? by Taattie94

Dirt Bike   Make / Model Specific   Yamaha   YZ 400/426/450
  • 1 reply

Join Our Community!

Even if you don't want to post, registered members get access to tools that make finding & following the good stuff easier.

If you enjoyed reading about "" here in the ThumperTalk archive, you'll LOVE our community. Come join ThumperTalk today!

The views and opinions expressed on this page are strictly those of the author, and have not been reviewed or approved by ThumperTalk.