Motorcycle Racing Forum

Motorcycle Racing => Wrenching => Topic started by: f4istuntin on May 20, 2006, 04:45:21 AM

Title: 929 fork
Post by: f4istuntin on May 20, 2006, 04:45:21 AM
going to be changing a set of 929 seals and oil soon. Any tips or online tutorials you guys can give me. Im mechanically inclined  only thing i havent really had much experience with is fork internals.  Just wanted to read up before i tore down

Thanks in advance
Title: Re: 929 fork
Post by: GSXR RACER MIKE on May 22, 2006, 08:15:20 PM
I'm replacing the seals, oil and upgrading the springs on my brothers 900RR currently (waiting for springs from Racetech). After you loosen the upper triple clamp pinch bolts make sure and break the cap loose on the top of the fork tubes before removing them, much easier that way. You may also want to break the allen head bolt loose in the bottom of the fork (below the axle) before removing the forks from the bike as well, but do NOT remove it or the oil will start draining out and the internals will be loose. After the forks are off, unscrew the cap to allow the slider tube to drop, then drain the oil out. Under NO circumstances should you clamp on the fork tube in a vice, unless you have the appropriate radius jaws made just for that purpose. Since your not doing spring or valving work you could ultimately just remove the allen head screw at the bottom of the fork and pull out the entire cartridge/spring/cap assembly - BUT.... your going to have a problem getting the oil level set correctly in the tubes when reassembling them since the oil level is measured without the springs installed. To take the cap off of the inner assembly your going to need a special spring compressor tool or a 2nd person to make it alot easier. While keeping the cap held in the position it's in when spring pressure is against it, you need to compress the spring so as to expose the nut just under the cap assembly at the top of the damping rod. You need to have a wrench on this nut and the cap to break it loose, removing the 'C' washer that presses against the nut may make things easier, but you'll have to see for yourself. I would highly suggest if you have never done this before to only disassemble 1 fork inner assembly at a time and keep everything in the order and direction it was in when assembled. Once the nut is broke loose you can unscrew the cap off of the damping rod, this will allow you to remove the spring, spacer, and any washers (remember to keep them in order!). Remove the inner cartridge assembly, then remove the dust cover seal on the outside of the fork tube to expose a clip that keeps the inner tube from coming out. Once the clip is removed you have to slide the inner tube outward with a little force to remove the inner guts, once removed replace what your going to replace.

Reassembly will require that you bleed the inner cartridge assembly, this is done after you install the cartridge into the fork and tighten the allen head screw at the bottom of the fork. Once installed pour enough oil in the fork to cover the inner cartridge assembly, then slowly pump the damping rod up and down to work air out of the cartridge, you should see bubbles and hear and feel the difference as it gets the air out. Make sure that as the cartridge fills as your pumping the damping rod that the cartridge stays submerged in fork oil, otherwise it will draw air into the cartridge. With out anything other than the cartridge installed set the fork oil level to the manufacturers suggested level with the correct weight and type of fluid, this is measured from the top of the tube when it is in the compressed position. Once the oil level is set install the spring and spacer then the cap assembly. This is something that you have to be careful with, the damping adjuster at the top of the fork needs to be set a certain way, and it is done as you screw the cap onto the damping rod - so don't just tighten on the cap without 1st finding out the correct way to do yours!

Good luck, if this is your 1st time it will be a learning experience for ya! LOL