Forks need to rebuilt..Questions??

To do a basic but essential rebuild to my forks what parts do i need to buy and wheres a good place to buy this stuff from? What is the difficulty on doing this rebuild?? Any hints or tricks on doing this rebuild? Thanks for any help or suggestions...

 

First of all you will need to take the forks apart, and drain the old oil into a container.
Under each fork leg is a bolt, usually a hex, undo this bolt. It holds the damper in place inside the leg. Hold the other end of the damper with something that will fit into the top of it, to stop it turning. It's another hex, and i try and use another bolt, usually from another part of the bike, depending on the size, old swingarm bolts or two large nuts trightened against each other on a threaded bar etc, some people have been known to use a broom handle or a long piece of wooden dowel.
Once this damper is removed and the clip holding the oil seal in, pull the legs apart with a sliding action, some force will be needed. When the fork comes apart it will pull the oil seal and bush with it. These are the two parts that need to be replaced for a BASIC service, the clip might still be usable.
If the fork springs are saggy or past their wear liimit it's a good idea to replace them as this will improve the quality of the ride no end.
To get the new oil seals and bushes in i use the old bush to push the new one in and a piece of plastic pipe, the type used in plumbing, the right size slid over the fork tube and gently tapped down with a rubber mallet.
You might need to replace the o ring at the top of the fork cap aswell, and don't forget to refill the forks with the right quantity and type of oil.
Hope this is of some use to you.

 

It was recommended to me - by a bike mechanic - to use a heavier fork oil on higher mileages to compensate for wear over the years, especially if they seem soft. If the manual states 10w, use 20w.

 

You'll need cap o-rings, circlips, fork dust seals, fork seals, seal clips, drain plug screw "gaskets" and new sealing washers for the damper rod bolts.

Check with XJ4Ever (logo/link in site banner, upper right) for the parts, he has everything.

To hold the damper rod while you break the retaining bolt loose, you need a 19mm hex of some sort. It can be a long piece of threaded rod with a couple of nuts jam-threaded against each other as suggested above, OR:

Find a spark plug socket that has a 19mm hex cast onto the outside of it. Flip it around, and attach to every 3/8" extension you have in your toolbox to make a really long 19mm "allen wrench."

Fork service is MUCH easier if you remove them from the bike first. Trying to do it what seems like the "easy way" (leaving the forks attached) really isn't.

 

This is a job you absolutely need the service manual for. Order that from Chacal with your parts if you don't have one. I think one of the bushings is replaceable on the 650, just ask Chacal to send you everything you need. Tell him to throw a pair of progressive springs in the box too - worth every penny.

I call BS on the fork oil weight change. If the forks are that shot the seals won't last anyhow.

 

Agreed, although I find Yamaha's recommended weights to be a tad light.

Personally I run 15W in place of 10W recommended; but not to compensate for worn out parts.

I too highly recommend an upgrade to Progressive Suspension springs; the original springs weren't all that great to begin with even when new. The improvement is quite noticeable.

 

I rebuilt my forks about a year ago - progressive springs, new shims for ~50lbs pre-load, new gaskets, dust covers, and oil - and have to agree it is WAY easier doing it off of the bike. You need a second person IMHO for some parts of it, and I think the book is a great idea. TAKE YOUR TIME with them - there is no point in starting and accidentally scratching them.

The Spark Plug socket really does work - just make sure you have 4-6 LONG socket extensions, the forks are DEEPER than you think on the inside.

The hardest part for me was getting the plugs out of the top ends (or more specifically putting them back IN and putting the clips in that hold them). I DID need a second set of hands for this part, and a fair amount of upper body strength and control for this part. I think I actually installed the forks back in the steering column to stabilize them (since I didn't have a way to safely clamp them) and sat on the bike and put the plugs in that way. (This was done after they were completely removed - it really IS easier to overhaul them OFF the bike, as stated previously by myself and the experts).

 

You might want to do some research on fork oil weights...it seems that they all vary quite a bit. What I mean by that is the 15W from one brand may be equal (viscosity wise) to 40W in another. I found it very confusing.
At the bottom of this link is a chart that helped me sort through the various brands.
http://www.peterverdone.com/archive/lowspeed.htm