Fork rebuild v3.0 including fork seal and bushing.

well, here I go again, trying in vain to improve my previous posts.

I’ll keep this one short, with some additional info that may help some of you.

You will need these tools:

  • You…the biggest spanner of all
  • Yammie manual, must have!
  • Spring compressor is a must for USD forks.  $40 from Traxxion dynamics
  • Level cyringe $20-30 from the local bike stealer.  You can make your own if you’re a cheapskate
  • 43mm fork seal driver.  Roughly $50 from the stealer.  Again, you can make your own…see cheapskate comment above.
  • 1L of fork oil.  5w is OEM recommened.  If you’re errmmm big boned, try 7.5W
  • Electrical tape!!! trust me, it’s needed
  • Two tie wraps, again read on.
  • Beer, or girly drink of choice, once manly job is done.  For the love of god…do not drink prior to finishing job, or you will screw it up

First off, the 1200 has USD forks.  With these bad boys, you need a $40 spring compressor to ease your life.  Without it you will end up breaking shit that was not meant to be broken.  Ask me how I know.

Here are the steps:

  • Pull the forks, and wipe off any excess grime, and dead things.
  • Take some electrical tape, and tape it loosely around the 14mm pre-load nut.  Back the preload in, till about 2 lines of preload are showing.  Get your 24mm socket, and while the fork is in your vice, with wooden blocks, spin the top off.  Once that’s done, back the preload all the way out, so the pressure on the spring is low.
  • IMG_7857

    Taped, and ready for the top cap to come off. Off into the vice it goes.

    IMG_7861

    Notice, preload all the way out, for less tension on spring. 14mm nut just visible. 17mm goes on the top cap body. Remember…righty tighty, lefty loosey.

  • Put the fork upright in the vice.  Get your spring compressor out, and compress the fork till the 14mm nut is showing.  Grab a 17mm wrench, and break the two.  Spin the top cap off, and slowly take the tension off the spring.  Set the plastic collar aside.
  • Pull the whole thing apart, leaving the damper in the bottom tube.  Pump all the old oil out.  At this point I usually dump in about 250ml of varsol into the bottom leg, pump it through the damper, and pump out all the excess.  Hang it upside down and leave it aside for re-assembly
  • Remove the  dust cap (slide it  down to the bottom of the fork) remove the  snap ring.  Holding the fork upright, give the bottom fork tube a few good tugs (joke joke), the whole thing will separate. and should look like the pic below.
  • IMG_7863

    Note the order of how things come together. Inner bush first, then outer bush, washer, fork seal, dust seal. I’m replacing the forks seal and outer bush only. Inner bush looked good, that and the fact that I didn’t order the inner one…duuuh.

  • I wash all my fork components in varsol.  In this case, the oil was original from the factory, and had a silvery sheen to it from all the metal that it collected.  Best to wash off as much crud as possible.  Let dry prior to re-assembly.
  • IMG_7864

    parts on hand. Two of each…obvs!!! Next time, i’ll buy the inner bush as well. The existing ones looked a-OK

  • Ok, we’re ready to install the new fork seal.  How the hell do you put the seal on without damaging it?  Well you need a fork bullet.  WTH is a fork bullet?  Think of it as a hardened rubber (hardy har har) but being a cheapskate, and having shitloads of electrical tape around, I simply wrap the fork with elec. tape, and on she goes.  Don’t forget to lube it for easy of entry (thank you thank you, I’ll be here all night, and please, don’t forget to tip your waitress!)
  • IMG_7865

    Elec. tape instead of fork bullet. Works well enough. pic shows new seal installed, along with new inner bush

  • Remove the tape, and break out your 43mm fork seal driver.  Use this to drive in the new outer bush first..  Dead easy, a couple of good whacks will seat it, and the sound will change, once you’re bottomed out.  Install fork seal.
  • IMG_7866

    Use your fork seal driver to seat the outer bush into the outer fork leg first. Once done, repeat on fork seal. Both should be easy peasy with your fork seal driver.

  • Now on to the oil.  Yamaha states 150mm of room, with fork collapsed, spring and guide out.  Pour in the oil, and stroke the damper to get all the air out.  You will feel resistance, as all the air comes out.  Once sorted, slap the fork in the vice, you’re on your way to re-assembly.
  • IMG_7867

    Fork spring and guide stay out for the oil measurment.

  • Ready for re-assembly.

    IMG_7868

    I always put a tie wrap on top, in case my compression lets the rod slip down. You can stop this by cranking your compression all the way up. Either way the tie wrap helps.

  • With the fork upright, throw the spring in.  If you’re keeping the stocker as is, the coiled end of the spring goes up.  You cannot cock this up, as the spring guide fit in one way only.
  • Compress the spring till your 14mm nut shows, install the top cap, and tighten down.  Slide the fork outer up, and spin the cap on.  Increase preload, so two lines are showing.  Use some elec. tape again, before you slap the 24mm socket on.  You are done one fork leg.. repeat for other!  Yay!
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4 thoughts on “Fork rebuild v3.0 including fork seal and bushing.

  1. Hey, thanks for this post; it’s going to come in handy, since I’m about to do my first fork oil change (as soon as I make a fork compressor). My question is, what’s the purpose for wrapping electrical tape around the pre-load nut?

    • If you have a socket that fits snugly around it, then you’re good to go. It’s so the soft aluminum doesn’t get damaged. Good luck. btw…the fork compressor is cheap from traxxion dynamics I believe…

  2. It’s cheap, but with shipping it ends up being almost fifty bucks. I have a bunch of scrap aluminum from many bike fabrication projects, so I drew up some plans to make a compressor out of the scrap on hand plus one of those woodworker’s trigger clamps. All it’ll cost me is my time, and I got plenty of that LOL. And thanks for the reply….your step by step is way easier to follow than the one in the service manual, so yours will be the one I’m looking at on my laptop while I’m cursing at my forks.

    • LOL. Well if you have the means…I couldn’t fabricate anything. Honestly once your fork is compressed, it’s dead easy to work on. Open chamber forks are just that easy to work on. My off road stuff is a PITA. I need two separate wrenches to undo the fork on my KTM 300, and that’s just a twin chamber. KTM went to a four chamber design, which is beyond retarded. My next dirt bike will be a fully adjustable open chamber 48mm fork. Easy to service (needs doing every 40 hrs) and easy adjustment (springs, valves, shims). Thanks for the great feedback Ron

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