How-To: Front Fork Rebuild

Since so many of us need to replace our front fork seals I'm gonna post the manual up here


 

 

 

 

 
 
 

 

 

 

thanks man....that project is definately on my list of to dos since locating a newer yr front end is about impossible for a good price without an e bay account.  but anyway does anybody have any pointers that are only found by doing the job? i.e. how much pressure is the tube cap under when it is unscrewed? am i going to have to look for it across my garage after i find my fingers or what.  any behind the scene info will be greatly appreciated. 

I Haven't done it yet, but mine started leaking last week, so I'm up for it now too.

Thank you so much.  I just pulled my forks, and they are sitting on the work bench.  I'll use this info to do the job and post up my results by the end of the weekend.

You're my savior!

 thanks a lot for posting this, I have been looking around the internets.

Now...once i stop being lazy and do this i'll let you guys know how it went

Alright, here are some notes on the fork rebuild.  The manual was pretty good.  If anyone has any more questions, post up.  Good luck!

Removing forks: I put the rear on a stand, and put some blocks of wood under the headers in the front, and then strapped the frame to the blocks of wood.

Removing caps:  I used a 15/16" socket and ratchet.  I HIGHLY recommend using a socket rather than a wrench because it allows you to keep the cap from shooting off.  It's under some pressure from the spring.  It probably wouldn't hurt your hand, but it would hurt your eye, so be careful.  When reinstalling the cap, you want to use a socket because it allows you to push down against the spring while twisting at the same time.  My forks had two spring seats (washers), one on either side of the spacer.  Pour out the oil, and keep a bucket and lots of rags right at your workbench.  It seemed like every time I took another thing apart, more oil came out, usually on the garage floor.

Socket bolts:  These bastards are TIGHT.  Used 6 mm Allen wrench.  I stripped one and had to drill the head off and drive to the hardware store to get a new one.  Not fun, so be careful.  The manual recommends reinstalling the fork cap and spring (and spacer)to undo these bolts.  The pressure from the spring keeps the internal parts from spinning.  It might be easier to remove the socket bolts before the fork caps to save you the trouble, if you can deal with the oil dripping out.  I didn't do it that way though, so who knows.

Dust seal and snap ring:  I carefully pried off the dust seal with a small flat head screwdriver.  The snap rings in my forks weren't actually snap rings, but were easily removed with the same screwdriver.

Separating fork halves:  Tap lightly.  Only tap hard enough to make the halves separate a little bit at a time.

Oil lock piece:  Mine got stuck in the fork leg, and I never got it out.  I still finished the job, so I don't know how important it is, but it would have been nice to be able to clean it.  Oh well.

Clean everything really well before reassembly, but don't get solvent on any rubber parts.  Clean oil can work to clean rubber parts.

Reinstalling socket bolts:  You have to get them tight, other wise they will leak oil.  The manual says 14 ft. lbs.  I did that, and they leaked, so I overtightened them.  It's up to you.  Again, the manual suggests reinstalling the spring, spacer, and fork cap to put pressure on the socket bolts.  To make the cap easier to thread on, I used a stack of large sockets totaling about 3/4" shorter than the spacer in place of the spacer.

Installing new seals:  Don't forget to oil them first.  I don't have the special seal driver, so I used a long flathead screwdriver and a hammer to drive the seals down.  This is a good way to ruin new parts, so if you do it this way, be VERY careful.  I tapped on the screwdriver lightly, accurately, and carefully.  Sometimes when pushing one side down, the opposite side would come up, so I had to hold that side down with another screwdriver.    A helper would be nice for this step.  You must drive the seal down far enough to fully expose the groove that the snap ring sits in.

Reinstalling fork cap:  Use a socket.  I found it very helpful to mark the spot on the cap and fork tube where the threads begin to catch, so I knew where to begin twisting the cap.  Don't crossthread this!  Aluminum threads are like butter, so be careful.  It should twist easily once its started.  If it doesn't, it's probably crossed.

Put 'em back on and your done.

These notes are not complete.  Don't break your stuff and blame me.  Motorcycles are dangerous.  Yadda yadda.

thanks bro... always nice to hear it being done from a real person rather than those guys who do the manuals. i think you covered all my questions about the job. now i get to make a new mess in the garage...awsome! 

Excellent description, HurricaneForce.  I had mine done at a local shop and had the springs changed at the same time.  Went to a non-progressive spring.

My bike was raced before I bought it, and it also had non-progressive springs in it.  What is the advantage to doing that?

Well, I can only tell you my opinion really.  It seems to me I have a better "feel" for the road now, and it definately doesn't dive near as much under braking.  I can't remember the units, but I went from stock (0.5) to 0.9.

So, I followed this procedure in my garage last week, alot easier than I thought it was going to be. 
 
  I do not have a bench vice to secure the fork while removing the socket bolts, I ended up using a screw driver in one of the brake caliper mounting holes to counter the torque, worked well. 
 I talked with a mechanic and showed him my fork cylinders, he showed me really small dings that would cause the seal to leak again, he advised me to go to a hardware store and pick  up some 600 emory cloth to smooth them out. 
 
 I ran into trouble installing the new seals, I started damaging the seal trying to tap it in with a screw driver and punch.  Went to ace hardware and found pvc piping that is a perfect diameter to fit over the cylinder and match up to the seal to work as a perfect seal driver.  I bought a 6" piece for $0.50, took it home sanded the driving edge to dull any spots that could damage the seal, then added a layer of tape just for slight padding.  It took like 30 seconds to install the seals.  Well worth the drive to ace and a couple quarters.
 
For adding the exact amount of oil I used an old bottle from when my son was a baby, they have .5 oz measurments on the side, worked well. 
 
Been riding it quite a bit and they are as dry as can be!

Cool.  Good ideas with the home made seal driver and baby bottle.

Alright guys, I'm doing the rebuild at this very moment, but I don't know how to get the old oil seal out? Or separate the fork tube and the slider... could anyone help me? I have everything out already except the hollow pieces (fork slider/tube). Help!

-Jasper

Wow, are you doing it the hard way!  The whole leg doesn't have to be disassembled to replace the seal... I usually remove the forks,caps, drain the oil remove the seal and slide the new one on press it in place, then reassemble.
 

.... How did you take the old seal out then? Please share.... please?

Slide the dust cover up the tube so it is not in your way. Remove the metal clip (i use a fine screwdriver and needle nose pliers). The seal is a press fit. sometimes if it is not tight just the friction of moving the tube inside will displace it. Most of the time you have to resort to a seal pick. in order go get a grip on the seal sometimes I take a fine drill bit and drill through the metal band (inside the rubber) and then use the pick to pull it straight up the tube. You have to use caution not to damage the fork tube or drill in too far and damage the seat.

You can check out the tool at etoolcart.com the part number is OTC7312
Seal pick.