How to: Rebuild your forks (F4 or F4i) (Full Version)

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How to: Rebuild your forks (F4 or F4i)

  

therabbit -> How to: Rebuild your forks (F4 or F4i) (6/11/2007 11:05:09 PM)

Fork rebuild seal leak front suspension

This applies directly to F4 and F4i forks since their construction and internals are identical (Only difference between the two is the fender mounting points). This is pretty easy to do, and will save you a couple hundred dollars over having a shop do it for you.

The tools you will need for this are:
  • 24mm wrench or socket
  • 14mm wrench x2
  • 8mm allen wrench that you can apply a lot of torque to
  • A couple small flathead screw drivers
  • A seal driver (see below on how to make your own)
  • Access to a table vise

Things you'll need from Honda:
  • Fork Oil
  • New Seals
  • New Bushings

Things you may want to do while you're in here:
  • Revalve
  • New Spring

Alright let's get started, first with the forks still in their clamps break loose the 24mm nut on top
[image]http://img458.imageshack.us/img458/3071/top24mmnutdv5.jpg[/image]
Loosen it just until you can see the start of the o-ring coming out.

Next remove the forks from the bike. Loosen the front axle, remove front fender, remove calipers, remove front axle, remove front wheel, loosen upper and lower clamps, remove handlebars, slide forks out of the clamps.

Now, keep everything organized and keep your forks seperated, no mixing parts.

With the forks removed unscrew the top 24mm nut the rest of the way, it is spring loaded, so when the last thread is undone it will kind of bounce a little.
You should be looking at this:
[image]http://img458.imageshack.us/img458/5746/topforkundonezv4.jpg[/image]

Put a 14mm wrench on the bottom nut
[image]http://img458.imageshack.us/img458/3158/14mmnutpg0.jpg[/image]
While holding onto that nut unscrew the big 24mm nut all the way off. If the part in the middle starts spinning try grabbing the top adjustment piece with the 14mm wrench instead and unscrewing it that way.
You're now here:
[image]http://img458.imageshack.us/img458/9540/topapartxa4.jpg[/image]

Remove the crescent shaped washer and the thin tube that it is holding in place. Now reach in and grab the washer sitting on top of the spring:
[image]http://img123.imageshack.us/img123/1595/springwashermq1.jpg[/image]

Now remove the spring, then dump the old fork oil into a suitable oil container, make sure you drain as much of it as possible, also pump the damper rod a couple times to get all the fluid out of it.

Next remove the fork protector (big plastic thing that sits on the end of the fork slider) use a flathead screwdriver very carefully to pry it up and off. (Sorry no picture)

Remove the dust seal in much the same way, just slide a thin flatblade screwdriver between it and the fork slider and slowly pry it up and pull it off:
[image]http://img458.imageshack.us/img458/4396/dustsealuy9.jpg[/image]

Once that is off look down into that crevice and locate where the ends of the snap ring are. Using a flatblade screwdriver pry the ring out by inserting the head into the groves and just pulling it out.
[image]http://img443.imageshack.us/img443/882/snapringyk2.jpg[/image]

Now put the fork slider in your vise with a towl wrapped around it so you don't scrape or scratch it. Use your 8mm allen wrench to remove the lock bolt on the bottom, it's torqued on there pretty tight, so it will take some work to get it out. (Note: While unscrewing the bolt, the damper may try and spin around, just grab onto it to hold it still)
[image]http://img102.imageshack.us/img102/8616/bottomallenheadxg3.jpg[/image]

Now remove the damper assembly (that long rod thing that's sticking out the inside of the fork tube) and set it aside as it's probably coated in fork oil still.

Next you'll need to remove the oil seal, which is wedged in there pretty good. Grab the fork slider and hold onto the fork tube and just start ramming it trying to push it out. You'll

  
Dirtytoes -> RE: How to: Rebuild your forks (F4 or F4i) (6/12/2007 12:44:20 AM)

this should be very useful, thx a bunch!

krash -> RE: How to: Rebuild your forks (F4 or F4i) (6/12/2007 2:33:06 AM)

NICE,  where you were last weekend when I did this myself?  nice find on the seal driver.

txn_driver -> RE: How to: Rebuild your forks (F4 or F4i) (6/13/2007 12:12:26 PM)

Anyone live close to Austin,TX that feels like coming over and giving me a hand rebuilding the front fork seal on my 900RR??? it looks simple enough i just dont have enough expierence working on bikes to dive in and try this myself, esp. with something as important as a front fork

axsys -> RE: How to: Rebuild your forks (F4 or F4i) (7/2/2007 10:11:38 PM)

well i followed this guide last weekend when i replaced my fork seals, and it couldnt have been easier! the tool worked excellent and was very easy to make. great writeup therabbit!

krash -> RE: How to: Rebuild your forks (F4 or F4i) (7/4/2007 6:59:00 PM)

I have a question about the position of the fork springs.  when I took my forks apart, the end with the coils closely together was at the bottom. However, my interpretation of the manual is to put the tapered end up, which is the opposite of how they came out?   I am sure there is a difference, since they are progressive springs, so which way to the closer together coils go?  I put them on the top.

I have been having trouble with my forks, which is why I took them apart a couple of weeks ago, mainly just to change out the oil.  the bike only had 1000 miles on it, but something just wasnt(still isnt) correct.  at stock settings, the rebound would top out and bounce and I cant get the sag correct.  after I put them back together, and set sag and played with the rebound dampening, its better but still not right.   I had to crank the preload adj down below any lines showing, just to get like 36mm of sag, and the rebound had to be turned about 3/4 harder to keep it from bouncing.    I also noticed while setting the sag, that there was excessive "stiction" when you compressed the front end, the forks would stick for a spit second before they actually rebounded, and then it would vary on its settling point in excess of 15mm.  Now I have also discovered a very slight, bump, or knock on the downstroke when compressing the forks.   uhhhhhggg!!!  these forks are 6yrs old, but had less than 1000 miles on them.

anyway, I made your fork seal tool, took about 10min in the garage, going to order some new seals, a guide bushing, and try all this again.    I know the springs are a little soft for a 180lb rider, but from stock I should not be having these issues.  I may go ahead and order some Ohlins .9 straight rate springs, but I think something else is really causing these other issues.  I may take the shim stacks apart just to make sure something hasnt gotten into the valving and clogged it from setting all those years.

Tom88x -> RE: How to: Rebuild your forks (F4 or F4i) (7/10/2007 11:14:41 PM)

i have a question, i just boought my 04 cbr 1000rr and noticed my left side front fork is leaking, i have not much experience with bikes and was wondeirng if the steps above would be fine for my bike, and right now i have the bike suspended in my garage and wondering how easy/hard it is to take off the fork all together,i already have the rim off but that is it right now, and also how much on average would it cost to repair this fork by myself and by a shop

therabbit -> RE: How to: Rebuild your forks (F4 or F4i) (9/19/2007 9:30:52 AM)

Sorry I'm so late responding to this, I never got an email about there being a reply to this thread...
To answer your question krash, the end where the coils are closer together should be on the bottom. To quote from the manual:
quote:

Install the fork spring with the tightly wound end facing down.

As for how this rebuild applies to other bikes, I have no idea. I do know it is exactly the same for the F4i and F4, but beyond that I can't be certain.

PlayfulGod -> RE: How to: Rebuild your forks (F4 or F4i) (9/19/2007 10:00:33 AM)

great write up! 

krash -> RE: How to: Rebuild your forks (F4 or F4i) (9/19/2007 11:56:00 AM)

yeah, a little late[:D]

but, I did finally get it all straightened out, I put the springs in the other way, didnt make any noticable difference.  So I replaced them with Ohlins, and cleaned out the shim stack, they had some type of gunk built up.  I guess from sitting for 6 yrs.

but all is good now

jahnaboi -> RE: How to: Rebuild your forks (F4 or F4i) (1/15/2008 5:51:58 PM)

Hey guys, I'm trying to rebuild my f2 fork and I don't know where I went wrong. What I did was as this:

1st - Removed the 24mm bolt to drain tubes
2nd - Unbolted dampening screw at the bottom
3rd - removed clip
4th - Tried pulling the fork tube apart from the fork slider

Now here's where I'm stuck... I can't seem to get the fork tube apart from the fork slider... Why is that when I unbolted and removed everything inside the tubes itself... there's nothing in the tubes except ... nothing. I can't get access to the oil seals very easily so that's why I wanna pull apart the fork tube and slider but what the **** am I doing wrong...

-Jasper

elmer -> RE: How to: Rebuild your forks (F4 or F4i) (1/15/2008 6:28:17 PM)

Jahnaboi, If I'm interpreting your problem correctly you just need to give the fork tube and the leg a few solid jerks and it should pop right out.  I'm thinking the seal should come with it because there's the race bearing type thing on the tube underneath the seal.  It's been awhile since I did my f2 fork seals but I think that should do it.

jahnaboi -> RE: How to: Rebuild your forks (F4 or F4i) (1/15/2008 7:05:37 PM)

I've been yanking on it for about 4 hours now.... it hasn't even moved let alone done anything but tire me out... I could bench over 200+ lbs and I'm pretty sure that should be enough to force it out... but still nothing... omfg... I'm getting pwned by this stupid stupid step....

-Jasper

Woody6799 -> RE: How to: Rebuild your forks (F4 or F4i) (2/17/2008 10:07:54 AM)

What is the stock weight? 10?

TBFGhost -> RE: How to: Rebuild your forks (F4 or F4i) (2/18/2008 6:22:11 PM)

Yes, the stock weight oil is 10 wt.  Someone should put that in the How-To part of this post were it can been seen easy. Also the old oil seal, a block of wood and dead blow make a good seal driver that will cost you nothing and you don't need to search for.   Push the new seal in s much as you can with you hand and then slide the oil seal down to it and use the block of wood and the hammer to seat the seal. 

  

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