Fork oil/seal replacement

[Scudman]

Just wrote this general guide.
Fork oil/seal replacement
No pictures at this time but as soon as I do a front end the pix will follow
This guide should help the user in replacing the fork oil, fork spring and fork seals.
As always this is just a guide, consult your maintenance manual for specific instructions as if you do not perform this procedure correctly you may get injured.
I have a spare fork spring compressor. You may borrow the tool free of charge but there is a $75 deposit which will be refunded at the return of tool

Procedure:

1 Lightly loosen all of the hardware that will need to be removed
2 Place bike on rear stand and then lift front wheel off ground
3 Top triple, clamp must be fully loose before loosening the top fork nut. Loosen top fork nut
4 Remove front brakes, wheel and fender
5 Loosen clip on?s
6 Loosen lower triple clamp
7 Remove fork
8 Repeat steps 6-7 for other fork
9 Using screwdriver unscrew the rebound dampener screw to it?s full up position (counterclockwise). Do this gently or you will ruin the screw.
10 Once the screw gently tops out count turns or click while screwing in the dampener screw until it gently bottoms out. Do not omit this step, write down the number of turns or clicks. Unscrew and top out the rebound dampener screw, this is important
11 Remove top fork nut

Upside down forks
1 Slide the aluminum top leg until it bottoms out
2 Place fork in spring compressor tool so that the hole on the bottom of the fork leg engages into the tool standoff
3 Adjust tool so that the top threaded studs of tool are lined up with the holes in the spring spacer which located on top of the spring
4 Thread the studs into the spring spacer holes
5 Using tool compress the spring until the dampener rod lock nut is exposed (usually a 14mm wrench can be used on the nut)
6 While holding the top fork nut with one wrench loosen the dampener rod lock nut with another wrench
7 Unscrew the fork nut and remove fork nut with attached dampening rod
8 Carefully loosen the spring compressor tool and release the spring tension
9 Remove spring, spacer and washers

Right side up forks
1 Slide the fork down until it bottoms out
2 While holding the top fork nut with one wrench loosen the dampener rod lock nut with another wrench
3 Unscrew the fork nut and remove fork nut with attached dampening rod
4 Remove spring and spring washers

Draining the oil
Drain the oil by placing the fork upside down over a container. When all of the oil has drained out slide the dampener rod up and down to drain the oil in the cartridge. Do the same with the fork (extend and collapse) until all of the oil is out

Removing and replacing the seal

1With screwdriver carefully remove dust seal by gently prying around the seal
2 Remove retaining clip that is under the dust seal
3 Remove allen bolt that is located inside the bottom of fork
4 While holding one end of fork slide the other end in the opposite direction until the seal, spacer and top for bearing come out. This step requires numerous extensions as the and seal is a tight fit
5 The seal, spacer and bearing will be on the chromed leg of the fork
6 Remove seal and clean fork leg
7 Tighten the allen bolt removed in step3 to correct torque value
8 Reinstall fork leg into aluminum slider
9 There are special tools for driving the bearing into the slider but a gently used screwdriver and hammer has been effective. I stress the word gently.
10 Once the bearing is seated place the spacer over the bearing
11 Place new seal on fork leg
12 Place old seal over the new seal and using a hammer drive the new seal into the slider. Note: the new seal must be seated full in order for the retaining clip to seat fully
13 Remove old seal and place the dust seal in position


Setting the oil level height

1 Pour oil in until it is approx. 100mm from the top of fork
2 Slide the dampener rod up and down until the fork oil comes through the dampener rod with no bubbles showing
3 Add oil to the level desired. To find oil level go to Race/tech.com. 110 mm is used a lot but check to make sure
Note: To set the correct level take wire coat hanger and bend at your desired level. While putting oil in, stop when oil level reaches the end of your tool. Use a flashlight

Fork assembly

1 Put the spring back into fork
2 Put the washer on top of spring followed by the spacer if any
3 Put washer on top of spacer
4 Make tool with coat hanger (make loop on one end and bend at a 900 angle to snag the dampener rod nut so that the rod can be extended past the spring top)
Pull rod past the top of spring. Safety wire can also be used. Lightly wrap safety wire below the dampener nut and place the spring and washers over wire
5 Place slotted washer under dampener rod
Note: Upside down forks need the compressor tool in order to compress the spring. Be careful doing this
7 Install to fork nut and dampener rod
8 Thread the fork nut onto the dampener cartridge rod
9 Screw in the rebound dampener screw and count the turns.
Note: If turns less than desired the fork nut needs to be turned out counter clockwise. If the turns are more than desired turn clockwise
10 when the correct amount of turns are achieved tighten the dampener cartridge rod nut against the fork nut
Assemble forks on bike in reverse order of disassembly.
Check your maintenance manual for proper torque values
Set your suspension rates accordingly as they have all changed

[02GSXXR]

THanx scudman great write up whenever you get sum pics up would be even better awesome thread

[Qomomoko]

great write up from Scudman.

there are about 5 threads related to fork oil

I am playing with my suspension and such and so learning about suspension fluid.

for my particular case:
Pregen ninja 250 with newgen ninja 250 suspension modded.
.75 kg/mm springs
recommended weight is 15wt from racetech ( I 'll call em again and see if they tell me their oil's viscosity and properties)

though our forks do not get got, I read it is recommended to get fluid with a index (which indicates its resistance to change it properties at higher working temperatures) of greater than 150.

also probably ordering a fork rebuild kit, not sure yet..

Wondering how you bike gurus can share some light on for oil info..

Race tech says they use Spectro Oil and Bel-ray oil is the closest in properties to it.

[Foxrider64]

Originally Posted by Qomomoko

great write up from Scudman.

there are about 5 threads related to fork oil

I am playing with my suspension and such and so learning about suspension fluid.

for my particular case:
Pregen ninja 250 with newgen ninja 250 suspension modded.
.75 kg/mm springs
recommended weight is 15wt from racetech ( I 'll call em again and see if they tell me their oil's viscosity and properties)

though our forks do not get got, I read it is recommended to get fluid with a index (which indicates its resistance to change it properties at higher working temperatures) of greater than 150.

also probably ordering a fork rebuild kit, not sure yet..

Wondering how you bike gurus can share some light on for oil info..

Race tech says they use Spectro Oil and Bel-ray oil is the closest in properties to it.

@Qomomoko- I run 15wt oil with .7 springs from Racetech in my newgen 250. I also cut new preload spacers to increase the preload. I did not do emulators or upgraded preload adjuster caps. Trying to keep costs down.

It has been working well for me.

[Qomomoko]

Originally Posted by Foxrider64

@Qomomoko- I run 15wt oil with .7 springs from Racetech in my newgen 250. I also cut new preload spacers to increase the preload. I did not do emulators or upgraded preload adjuster caps. Trying to keep costs down.

It has been working well for me.

nice…

I have all the parts to start the build again (excepts brake pistons)…. ended up getting Spectro Fork oil SAE 5. This was after much talk with them. Will adjust after I ride the bike.

I am also about 15# heavier but will loose the weight as I pick up exercising the .75 spring I got be a better fit.

[Scudman]

I typically start with 10W oil and this works with the adjustable suspensions. It works quite well on the street and the adjusters are placed at the lower levels. Mostly close full out. With the lower viscosity your adjusters will be mostly fully in. You may have to try different oils until you get the right combination. The level is important as that changes the spring rate of the suspension. On your 250 15W seems to be about right and adjust the oil level higher to make up for soft springs. You may want to skip the spacers as they do not change the spring rate. They only adjust the height of the bike. Fork oil height will also alter the height of the bike.

[anarion55]

Before going through the time and mess of rebuilding... try this first - in many cases it's just some dirt trapped under the seals that is causing the leak, and this little gem will do an amazing job of clearing it out...

Amazon.com: Motion Pro Seal Mate Fork Seal Cleaner: Automotive

Amazon.com: Motion Pro Seal Mate Fork Seal Cleaner: Automotive

[Larry33319]

I second what Tony says. I have been using them for about 10 years or so and have not had to change a seal since then.

[dave ls1]

Originally Posted by anarion55

Before going through the time and mess of rebuilding... try this first - in many cases it's just some dirt trapped under the seals that is causing the leak, and this little gem will do an amazing job of clearing it out...

Amazon.com: Motion Pro Seal Mate Fork Seal Cleaner: Automotive

Well worth the asking price, easy to use, and takes up almost no space at all in the toolbox...

How have I never seen this. That's brilliant.

[blindstuff]

I used to do that on my WR250 with a simple piece of bond paper. Always worked just fine.