FORK OIL RERPLACEMENT

[GUMBYBOB]

I'm attempting (for the first time) the basic fork oil replacement. I really don't know what to expect. I'm just planning on popping off the caps and filling that way. Not removing the forks. It sounds like when the caps come out, a damping rod comes out with it but I don't know.

1. Should I drain one fork at a time so it's easier to pump out the oil?

2. Isn't the stock weight 7.5? Carlos's instructions specify 10, I believe. I only ride one-up so I may not need heavier oil. I weight 175 lbs.

3. Is this a 2 man job?

4. How tight are the fork caps on? Will I struggle with a breaker bar if the've never been off before?

5. What's the most accurate way of knowing how much oil to put in? Measure volume of what I'm dumping in or measure the distance of the existing oil level with the cap and damping rod out and fill it up to that level?

I may have other questions as I think about this more.

Thanks for your help.

[Northman]

Remove the forks.

You need to pump the damping rods to remove the oil, and bleed them after.

You could drain the oil by removing the bolt in the bottom of the fork, but it's a PIA, IMO.

How many miles on the bike? If your mileage is low, then a straight fluid change will suffice, but if you've got 20K on it, you might want to flush the valves and tubes.

Stick with the stock weight oil. You're at the right weight for the suspension, according to Racetech, so just use what the manual recommends.

[GUMBYBOB]

I have 23,000 miles .

[Northman]

Loosen the caps before you remove the forks from the triple, and you'll need a special (long) allen key to remove the bolt in the bottom.

[HERBXX]

Ive done it on the bike a couple of times , i just pull the cartridge out to

work on it and leave the forks on.

It works for me. The worst problem i have is the nose piece falling off the cartridge when i lower it back in the fork. Now I tap it on real good before putting it back in .

Just my 2 cents

[GUMBYBOB]

HERBXX

What have you done with your front suspension?

And do the springs come out WITH the top caps?

What's the cartridge consist of that is attached to the caps?

[Alanb]

I used a piece of coat hanger with a hook bent into the end to "grab" the springs and the edge of the damping rod when it sort of fell down too far into the tubes. Actually wasn't too bad, provided you can get the allen bolt out of the bottom. And the axle has to be removed to get access to it, I didn't see that anyone had mentioned that for you either.

Alan

[Edward]

I do my forks every spring.

1st, jack the front tire off the ground, a floor jack under the motor, "a piece of wood between metals please"

Remove the front fender, brake caliper mounting bolts, front tire and handle bars.

Loosen the top triple clamps and the fork caps.

Then loosen the lower triple clamps and remove the forks.

Once you have them on the bench, take either one and place it in a vise, "again please utilize some kind of protection between metal pieces".

Take the fork cap loose, "there is some pressure from the spring so it does helps to counter this"

Once cap is loose you will find that it is connected to the dampening rod, loosen the locking nut and screw the cap off.

Pull the spring out, "yes there is some oil spillage"

Take the fork loose from the vise and dump the old oil out.

To remove the oil that is still in the dampener you will have to turn the fork rite side up and pump the dampening rod then dump the oil again, "do this untill your satified with the results.

Your now ready to put some fresh oil in, honda calls for 438 + - 2.5cm, or you could just measure.

Compress the fork, pore a small amount of oil in, pump the dampener rod till you have removed all the air and you have full resistance.

With the fork still compressed, take a measurement from the forks opening to the oil level, your looking for 142mm/5.6"

Going back together

Grab hold of the dampeing rod with something, "I use an old hose of about 18" in lenghth

Install the lower spring shim, the spring, the upper spring shim, the spacer, then the spacer to cap shim,

Screw the cap all the way onto the dampner rod, then tighten the locking nut. Push the cap down and screw it into place.

Repeat these steps on the second fork and a bit of lock tight of the brake caliper mounting bolts and your done.

Enjoy.

[gcp]

Edward, would you happen to have pictures of your procedures? Very good info, thank you for providing it.

BTW, I've asked previously but received no answers, so here it is again;

I've been thinking on tackling my BB's suspension next, what's the most cost effective way to improve it? Could some one please explain the spacers in the front and the appropriate weight oil I will need as a first step? Or, which is the best progressive springs set I can buy to drop in?

On the rear, what's the simplest solution? I think my rear spring is adjusted to its max possible hardness and I still scrape now and then when, 2 up, I go over speed bumps. How does one install a spacer to increase height? I assume if I raise the front the rear will also have to be equally raised.

I plan to do quite a bit of 2 up riding, I'm 195 and my wife is 125 lbs.

[pai]

i have 40k km but i have never changed my fork oil. what will happen?

[HERBXX]

BOb, I have installed racetech valves and 1.0 kg springs. I've taken them out two or three times to tune them . The springs are held captive

by the damping rod , which screws into the fork cap. The cap will pop

up a bit when you take it off so keep pressing down as you unscrew it

so you don't tweek the the last thread on the cap.

If you get a look at the manual it will become a lot clearer.

Herb

[Pete in PA]

For GCP:

Watch it on those speed bumps, you'll crush your exaust!

What I did was using stock fork springs make shims from the correct diameter of PVC pipe. I can't remember the length I used. Had to install and remove a little length a few times. What you want is 1 1/2" of sag. with your weight on the bike.

Put bike on centerstand and jack up front of engine to get tire off ground.

Remove handlebars, break nuts on top of forks loose. When unscrewing watch for slight spring press. when releaseing. unbolt damper rod from fork cap. install your shim. reassemble and remeasure your sag. Shorten your shim untill right.

For your rear, I seriously doubt your spring is maxed out. I'm 280 lbs and I have it set for 1 1/2" of sag and have lots of thread left.

You have no threads left UNDER the adjuster rings?

I had to remove the rear shock to break loose the lock ring then reinstall and adjust.

I have never changed fork oil in any bike I've ever owned till the fork seals leak. Then it gets changed. When's the last time you changed your strut fluid on your cage? What's the difference?

This whole procedure has been covered in the bike rags (and I'm sure somewhere online) over the years.

Hope my tutorial isn't too rough, It's still early this morning. :oops:

[gcp]

Pete I read your procedure and no your directions are fine but I do have a couple of questions;

1) When you say you doubt my spring is maxed out, in what direction? I checked and the lock ring and nut are at the very top of the shock’s threads so I don’t believe there’s any more room to take it up further.

2) My weight is 195 lbs and alone I’ve not had a problem in bottoming out. But when 2 up with my wife, who is 120lbs (our 315 lbs > your 280 lbs), over speed bumps I’ve bottomed out twice now. And if I install and pack the saddle bags for a long weekend it's bound to get worst so I feel I need to do something to solve this problem.

3) Your front PVC shims, could they have been in the ¼” = 6mm range? Or do they need to be longer than that? Demon recommends a 6mm spacer on the rear spring that’s why I’m asking, plus I seem to remember reading somewhere that the front shim need to be 6mm but I could be wrong.

Thanks a bunch for the info,

[Redbird]

the lock ring and nut are at the very top of the shock’s threads

That's as soft as it can be. Turn it down to compress the spring and firm it up a bit. Set your sag on the firm side (around 30mm) with just you on the bike and you should be fine with the wife on back occasionally.

The 6mm spacer has nothing to do with preload, it goes on the upper mount and will raise your rear around 3/4" regardless of preload.

[Pete in PA]

Yeah, what Redbird said. Your rear shock is at its softest. You need to squeeze the spring tighter, run the preload rings down towards the ground.

For the forks, roughly geusstimating, my shims are a little less then 1 1/2" long but it's been a while since I did this and it's based on my weight. Start long and shorten till you get the correct sag.

good luck,

Pete

[MacBirdXX]

Send me you email and I'll send the pages from the shop manual from my aprilia. It has photos. It also has the 43 mm U Showa forks and its the same damn proceedure. I just replaced the prilers innards with the same racetech stuff I bought for my bird. Same part numbers and all straight from the website.

[gcp]

I guess the guy I bought my BB from has the rear set up for a soft ride since he rode 1 up. Thanks gents, after all this info it looks like I'm on my way to setting up my BB's suspension.

MacBirdXX my email is gcpgcp@yahoo.com

[gcp]

My bad guys, after today's closer inspection the rear shock is set at its hardest possible setting so there's no more room for adjustment. So, per demon's instructions I placed a couple of washers under the rear shock (.240") and I was surprised at the rideability difference it made. Not a long ride mind you but the bike felt quicker responding in the front, plus when placed on the center stand the rear tire almost touches the ground, which indicates that the bike will now ride higher and will be less apt to bottoming out when 2 up. Plus it's much easier to put up on its center stand. So far I like this mode but I need to ride the bird more extensively so as to validate my first impressions.

Thanks demon, you gave me one heck of a suggestion!! :grin:

[Pete in PA]

I'm still surprised your shock is maxed out full hard. If I did that to mine it probably wouldn't even move on a bump!

Where exactly did you put the washers? If you used them to increase ride height it won't help the shock action itself.

[gcp]

Pete, the washers were placed in between the top of the rear shock (actually at the bottom of the threaded portion that bolts the shock to the bike) and the bike's cross member. So, this fix essentially raises the seating position of rider/passenger and changes the geometry of the bike front to back. This change of both seating position & geometry I am hopping will be enough to not allow the exhaust to scrape speed bumps but maybe not.

You are right though, it does not change the stiffens of the spring, not that we have ever bottomed the spring out anyway so, maybe this fix will solve my particular problem.

[Pete in PA]

Now that you increased rear ride height you really have to tackle the forks.

[gcp]

Yep, I removed the GenMar caps yesterday to see how easy it would be to remove the fork springs without having to remove anything else. I think I can fit in there a socket but I've not tried yet.

Is there anything else I need to know before I get into it? Will I need a spring compression tool for example or will I be able to push the spring cap down and hold enough to start the threads without cross threading?

What ID/OD size was the PVC tubing you used for your spacers? Is PVC hard enough to not chip or break in hard cornering? Does it not dissolve due to the fork oil additives over time? Is there a maintenance schedule you follow?

Thanks,

[Pete in PA]

No tool needed, just carefully turn nut on by hand so you don't cross thread it. With spacer it will be under a little more tension.

PVC has been used for this forever. I've never heard of a problem with breakdown of the PVC.

I wish I could tell you what size PVC but It's been awhile and I've got lots of various PVC in the basement. Not taking it apart to check for you. sorry. :cry:

There is a factory spacer in there already. The spring doesn't go against the fork cap like on other bikes. Just take it out and take it with you to Lowes.

Do you have a manual? It really makes this much clearer. Honda manuals are the best, lots of pics. Ever see a Kawasaki manual? YUCK!

[gcp]

Wonderful, thanks for the directions gents, looks like I'll have something to do Saturday morning other than ride, damn rain!

Yes I do have a Honda manual but have not looked at it yet, being an engineer I've long ago rendered all manual unnecessary....unless I am stamped, and that happens more often than I care to admit :wink:

rockmeup, if I was 90lbs would I be complaining about my bird's suspension?

[gcp]

I took the cap off the left fork tube on my lunch hour but the cap's connected to a rod and doesn't seem to want to come out of the tube or the rod, is there a trick to removing the cap so I can install the spacer? BTW I bought two 3/4" couplings from HD that are 2.25" long and 1"OD for a total of 30 cents, costly fork springs fix, if I can ever complete it :roll: . Also I didn't see the spring extending off the fork tube, is it recessed in there?

I had to take the GenMars off to do this so I thought I'd try the bike without them. So far I seem to like it better without than with, monkey arms you see, what are these things worth?

Thanks,