Fork Oil Change

[runner]

Starting with the advised fr-end upgrades, is the fork oil change as straightforward as pulling the forks off , removing the cap, and dumping out the old oil?

My shop manual goes thru the full rebuild procedure and doesn't reference separate fork oil change procedures.

Any special things to watch for would be appreciated (fork springs under compression...obviously!).

If the oil change doesn't help enough I will move on to new springs...but I am starting with the basics....thanks

[Stinger_916]

Starting with the advised fr-end upgrades, is the fork oil change as straightforward as pulling the forks off , removing the cap, and dumping out the old oil?

My shop manual goes thru the full rebuild procedure and doesn't reference separate fork oil change procedures.

Any special things to watch for would be appreciated (fork springs under compression...obviously!).

If the oil change doesn't help enough I will move on to new springs...but I am starting with the basics....thanks

I would say it is really straight forward but I would not remove the allen bolt at the bottom of the fork. You are asking for troubles if you do that.

Also you want to loosen the 23mm ( I think that's the size) bolt on top of the forks before you take them out of the trees. This makes removing it sooo much easier. When I did this procedure I had a bit of light weight oil, like trans fluid handy to flush out all the oil fork oil. I just added a few oz's and worked the forks up and down a bit then dumped out what was left over. I was amazed how much old fork oil came out after doing that.

Last thing was to make sure you have an accurate measuring device for when you put the fluid back in the forks. This way you won't have to much or to little in either fork.

I hope that helps you

[rideonXX]

Don't get in a big rush----let them hang upside down of course from a rafter or something----you will be surprised how much more shit comes out.

Then fill as directed in the manual----precisely as the manual directs---skip any steps and you have fucked up. Happy trails kel

[Hobicus]

1) Put the bike on the center stand

2) Remove the front fender

3) Remove the handle bars/clip ons. Loosen the allen, wiggle them up and loose. Make a note of what lines run where, you will be thankfull when you're re-assembling everything.

3) Loosen (break free only!)the bolts on:

The front wheel (4 12 mm bolts, 1 22 mm big bolt.

Both brake calipers, including the ones for the LBS and the lines.

Using a 24 MM socket, loosen the fork caps.

4) (if you have a front end stand, that goes inside the steering stem, you can skip this step)

Put a block of wood on your jack, and roll the jack under the oil pan and jack up the front end until the front wheel is off the ground. The bike should be pretty stable. if it wobbles on the wood, re-position it and try again.

5) Remove the brake caliper bolts on the right side of the bike, and work the caliper loose.

6) remove the 22 mm nut holding the axel in place, and pull the axel out. Make a note of where the spacers in the wheel are, you will thank me later.

7) Remove the rest of the caliper bolts from the fork, loosen the 10 mm bolts where ever the brake lines mount to the fork tubes.

8) Once you have all the brake lines free, there's a 14 mm and an allen holding each fork tube in place. Loosend the fork tube, and it will drop right out.

9) Before you do ANYTHING ELSE, spray the fork tube down with Honda Polish (or equivalent) and clean up any bugs/dirt/etc that might be on the tube. This will help keep your seals from leaking.

10) I remove the allen bolt from the bottom of the tube when I do mine. I just makes emptying them so much easier, and certainly more thorough. I usually need to take the fork, and putting the base in my vise, I can usually just break it loose. I do each side. IF it will spin but not come free, I take it out of the vice and with it upside down (note, I have not removed the end caps yet!) I push down on it, and turn the allen. That usually works. As long as the end of the allen isn't boogered up, you can also try using a longer Allen with an impact wrench, and spin it out.

IF the end is boogered up, I just remove the fork top, since getting it out is going to be a giant pain.

11) With the allen out, when you turn the fork over, oil will start to leak, so put the end in a bucket ,and remove the top fork cap (you loosened it before you dropped them, but you may still need to put a wrench on it to get it to come free. Once you get the cap loose, the oil will flow pretty quick. Find the brass washer behind the allen bolt, sometimes it gets stuck up inside.

12) To pull the cartidge out, you will need a 14 mm wrench to loosen the nut under the fork cap. Loosen the nut, and the cap will come all the way off. You can then pull out the spacer and spring. Make a note of the order and orientation of the spring, so you can put it back together the same way. (as I remember, it's narrow end down)

13) Pull the cartidge out, and pump it a BUNCH of times. You will find that it takes quite a bit to get the oil out of it. I have been known to spray it down with brake cleaner to clean it up, too.

14) I usually clean up the spring and spacer as best as I can, using a shop towel and occasionally using some brake cleaner. In the end, you want to make sure everything's as clean as possible.

15) When cleaning inside the fork tube, it's usually a good idea to rinse it out a bit with oil too. You also want to clean the underside, where the allen bolt will seat with the brass washer. It's a good idea to plan on replacing the brass crush washer. I've reused them on a regular basis without incident, but I did have one incident where it leaked. As it turned out, I had not cleaned the underside well enough (Where the brass washer seats, and it left enough dirt on there that it leaked.

16) To re-assemble, first put the cartridge inside the fork tube. I usually put the spring and the spacer/washers in as well, without oil, and put the fork cap in place, too. Then I start the allen which holds the cartidge in (see above about the brass crush washer and getting the dirt out of there!) until it's tight. Pushing down on the fork tube, compressing the internal spring, is usually good enough to get it to snug down nice and tight. Your shop manual will have a torque spec, but it's been my experience that it's usually worth taking down to the vice and making sure it gets nice and tight.

Note: some people like to put permatex on the bolt for extra leak protection. Like I said, if you get the surfaces nice and clean, you should be OK, but it's your call.

17) Once the cartridge is back in, you take the fork cap off, and remove the spacer and spring, too.

There's 2 schools of thought as to how to fill the tubes with oil:

1) Measure with a graduated cylinder.

2) Over fill and use a Mity Vac to extract any extra.

Because the only way to know if you got it full is to measure how much oil's in there, I use the 'Over fill and Extract" method, as taught to me by Redbird. I don't remember the stock height (230 MM comes to mind, but I will check my manual when I get home and update the post. EDIT 142 MM, not 230!) But basically here's the process:

Fill the fork tube most of the way up with oil. Pump the inside cartridge up and down about 20 times. After the first few times, you'll find that it gets much tougher to move, as it's filling up with oil. Try to work it the full length of travel. After you're sure you got all the air bubbles out, you're done.

Tape a piece of wire with the tube on your Mity Vac (to keep the tube straight). Measure from the bottom of the tube up to the height you want it to be (so.. 142 mm, or 14.2 cm) and mark the tube. A smart guy bends the wire so it can hook on to the tube, but make the mark as accurate as possible.

Holding the fork upright, without the spring or spacer in there, with the tube all the way DOWN, (having a helper here makes it much easier) put the Mity Vac tube inside the fork tube down to your mark. Now suck out any extra fluid, holding the tube at the mark the whole way. When you start sucking air, you've got it to the proper level.

[uPDATE 4/23/2008: According to my service manual, for 99-03 XX's, that number is 142 MM, or 5.6 IN, not 230 as previously posted]

After that, it's pretty straight forward:

18) Put spring, washer and spacer in fork. Tip: Pull up on the inside cartridge first.

19) Attach cap to the cartridge top. Spin down to the to pof the 14 mm nut. note that the goal here is to get them even. so make sure the nut is at the same level (and tight!) on both sides.

20) Push the cap into the tube, and tighten. This can be somewhat tricky, and a helper is usually good here if you need someone to hold things. If you dont' get it super tight, that's fine, just get it snug.

21) Put the fork tube back in the bike. Raise it up until it's 1.5 inches (I will dig up my manual, as listed above, but that's what I remember) fromn the bottom of the fork cap to the top of the triple tree. Tighen down up at the top tree first (because it's easy to get to) but don't forget to tighten the 14 mm bolt on the lower tree, too.

When fishing up the forks through the trees, pay special attention to the position of the wires and brake/clutch lines, they should be where they were when you pulled the fork out.

22 ) Once the forks are back in the trees tighten down the caps one more time, now that you can torque them properly.

23) Replace Handlebars - Do not pump brake handle, though!!!

24) I usually take this time to spray the brake calipers with cleaner and push the buttons/pads back inside the caliper. Makes assembly easier, and you'll be amazed at how good your brakes feel for a while

25) Install brake line bolts in the forks, and put the front wheel on (check direction of spin) Snug the front axel bolt, but not the 4 pinch bolts.

26) Lower the bike off the jack. Torque the front wheel bolt.

27) Install the brake calipers. Note that while a properly torqued bolt shouldn't fall out, I would recommend using at a minimum blue loctite on the caliper bolts. I HAVE had them fall out.

28) Pump up the brakes. Make sure they are nice and working.

29) Using the brakes, bounce the bike on the new forks.

30) Tighten the pinch bolts on the fork tubes. (Yea, I know, it's silly, but that's how the manual says to do it)

31) Replace the fender.

As with any major change to the bike, before you go balls to the wall, take it easy for a bit on your first trial ride.

[blackhawkxx]

You just can't get a better write up than that. Did you do any work today?

[rideonXX]

Nice write up Hobicus. The part about bouncing the front forks before you tighten the one pinch bolt isn't silly, it's critical! What is does is align the fork lowers on the tubes. Just a tiny bit out of causes bunches of stichen that makes the fork sluggish at best. I have someone help me so that I get full compression of the forks every time the folk leg/axle pinch bolts are loosened.

A great DVD explaning suspension and the stichen issue is Suspension for Mortals from Traxxion Dynamics.

Thanks for taking the time to do the great write up. Happy trails kel

[Hobicus]

You just can't get a better write up than that. Did you do any work today?

That took me an hour. I was officially doing "Paperwork".

It could have had pictures...

(no comments on the messy garage)

These were taking when I was restoring the 97 XX. Normally you wouldn't take off the upper and lower cowl

Front wheel off, block of wood under oil pan

Looking down from the triple trees.

Loosening the fork caps

Pumping the cartridge rod to fill with oil

Pumping out the excess oil. Notice the white piece of wire hanging over the edge of the fork tube.

Measuring fork tube height

Replacing the handlebars

[beondwacko]

Hobi,

I'll be following this handy guide sometime this winter to change the oil out on my forks(along with changing the springs). I'm so overdue for this that I'm ashamed(01' 20,300 miles). I hate the way the front end rides stock. As if it's over damped and under sprung. For some reason or another though,,,,,,,, I just hate the idea of doing this.

Here's a quick question:

What is the easiest / most effective manner to add the correct amount of oil into the tubes? Dipstick method or just premeasure the amount going in?

[Para045]

This is a great write up Hobie and well timed as I have a set of 04 forks with Ohlins valves and 1.2kg/mm springs ( for my 300lb arse ) waiting to go on my 98 XX in the next couple of weeks and this will make it so much easier than the way the manual says to do it

Just one thing - you say that the upper and lower cowls don't have to come off?

Doesn't it make it hard to undo the triple bolts and other bits and pieces :icon_think:

I think I will probably need to take the cowl off anyway to do the All Balls Steering Head Bearings

Hobie, Here's a quick question:

What is the easiest / most effective manner to add the correct amount of oil into the tubes? Dipstick method or just pre measure the amount going in?

There's 2 schools of thought as to how to fill the tubes with oil:

1) Measure with a graduated cylinder.

2) Over fill and use a Mity Vac to extract any extra.

Because the only way to know if you got it full is to measure how much oil's in there, I use the 'Over fill and Extract" method, as taught to me by Redbird. I don't remember the stock height (230 MM comes to mind, but I will check my manual when I get home and update the post.) But basically here's the process:

Fill the fork tube most of the way up with oil. Pump the inside cartridge up and down about 20 times. After the first few times, you'll find that it gets much tougher to move, as it's filling up with oil. Try to work it the full length of travel. After you're sure you got all the air bubbles out, you're done.

Tape a piece of wire with the tube on your Mity Vac (to keep the tube straight). Measure from the bottom of the tube up to the height you want it to be (so.. 230 mm, or 23 cm) and mark the tube. A smart guy bends the wire so it can hook on to the tube, but make the mark as accurate as possible.

Holding the fork upright, without the spring or spacer in there, with the tube all the way DOWN, (having a helper here makes it much easier) put the Mity Vac tube inside the fork tube down to your mark. Now suck out any extra fluid, holding the tube at the mark the whole way. When you start sucking air, you've got it to the proper level.

[Guest cudgel]

I agree it is a nice write up and guide to follow by Hobicus and should be saved. I might add that washing things out that have contained petroleum products can be done with good old soap and water if completely dried afterward. I often weld on tanks that I have to wash out either gasoline, or diesel, or jet fuel and have always used Dawn dish soap. Won't risk my life otherwise. On fork oil changing, you can go an easier way if not changing springs. Remove front wheel and fender. Remove Allen bolts in bottom of fork leg with small air wrench. Place graduated containers under them and loosen fork caps and pull them up and to the side for air to enter. Go to the movies, make love to your sweetie, or find something to do for about three hours while the forks drain. If the levels are equal at almost 16oz/ leg, that's all you will get as Honda says fork capacity is 16.3oz. Replace Allen bolts using new crush washers and refill exact amount you removed. I have just done it this way and used 5w SAE Spectro oil. Reasons for going this route for me were: I'm light enough, 147lb, that the springs might suit me and my bike is lighter being naked. Also the fact that all the nasty stuff in the forks is at the bottom and will mostly come out that way without gumming up the works like changing engine oil. The 5w helped in my case a lot. The overdamping is mostly gone and the spring rate seems about right. These forks still aren't the best but the improvement is very noticeable. If I had the time to try 2.5 or 3 wt I might see a further improvement, maybe not. Next, the shock.

[Fast Eddy]

Dam Hobie has nice legs

[Hobicus]

Dam Hobie has nice legs

Next time I'll wear my wrenching heels.

[OMG]

Awesome write up!!

Only thing I could add (having been a factory mechanic for honda and bmw) is to not install the springs and add the oil till you have verified that the forks slide freely after all the bolts are tight. I know it can be a challenge, but sometimes the tubes aren't perfectly true and can cause a sticky action. Rotating one or both of the tubes can often resolve this.

[pcinpdx]

Hobi,

I'm pretty sure I understand but want to double check with you on refilling the fork tubes. If using the overfill method do I create an apparatus that looks something like this:

I take it that I would insert this into the fork tube until it touches bottom and then suck out everything to the bottom of the MightyVac tube which would be right at the 230mm mark - correct?

[Hobicus]

Hobi,

I'm pretty sure I understand but want to double check with you on refilling the fork tubes. If using the overfill method do I create an apparatus that looks something like this:

I take it that I would insert this into the fork tube until it touches bottom and then suck out everything to the bottom of the MightyVac tube which would be right at the 230mm mark - correct?

No.... You're not measuring from the BOTTOM, you are measuring from the TOP

Here's a picture:

(Edit: Changed 230 to 142, according to manual)

[pcinpdx]

Sweet.

Thanks for the quick response and setting me straight. It's all making perfect sense now.

[Redbird]

You might check that 230mm number, too. I know there were were changes to the specs which included fork oil level, but I'm pretty sure my '01 was supposed to be set at 140mm. Check the manual and make sure you've got the specs for your model year before buttoning it up.

[02XXCA]

I did mine the lazy way and just removed the bolt on the bottom of the tubes and pumped the forks.

[XXTi]

I think my bike uses the 140mm measurement too.

I removed my forks for the oil change, but I did not remove the cartridge. I just drained the oil, filled the forks with kerosene and pumped the hell out of the rod. I changed the kerosene a few times and was surprized at how much shit came out of the tubes.

After the kero wash, I turned the tubes upside down and pumped the rod until all the kero was out of the forks and cartridges. That was 10k miles ago and I've had no problems with the forks.

[pcinpdx]

You might check that 230mm number, too. I know there were were changes to the specs which included fork oil level, but I'm pretty sure my '01 was supposed to be set at 140mm. Check the manual and make sure you've got the specs for your model year before buttoning it up.

Thanks for the tip. I'll definitely consult the manual to make sure I've got the right numbers

I did mine the lazy way and just removed the bolt on the bottom of the tubes and pumped the forks.

I'm almost positive that's what I'll do next time but if I can tear it down, see how it works and put it back together again without majorly fucking something up, it gives me some sense of accomplishment.

[Hobicus]

You might check that 230mm number, too. I know there were were changes to the specs which included fork oil level, but I'm pretty sure my '01 was supposed to be set at 140mm. Check the manual and make sure you've got the specs for your model year before buttoning it up.

Tim is correct... I just checked my manual (as promised months ago, but I got lazy) and the number for 99-03 is 142 MM, or 5.6 IN, not 230 as previously posted.

I've edited the original instructions, and will update the graphic shortly.

[lexxus]

I've been doing it this way, All the time

My bike,Full fairing, forks off, is the only way i change my fork oil.

[Para045]

I removed my forks for the oil change, but I did not remove the cartridge. I just drained the oil, filled the forks with kerosene and pumped the hell out of the rod. I changed the kerosene a few times and was surprised at how much shit came out of the tubes.

After the kero wash, I turned the tubes upside down and pumped the rod until all the kero was out of the forks and cartridges. That was 10k miles ago and I've had no problems with the forks.

Yeah thats how I did mine

I just checked my manual (as promised months ago, but I got lazy) and the number for 99-03 is 142 MM, or 5.6 IN, not 230 as previously posted.

My 97 manual says 154mm Wonder why the difference

[Hobicus]

I removed my forks for the oil change, but I did not remove the cartridge. I just drained the oil, filled the forks with kerosene and pumped the hell out of the rod. I changed the kerosene a few times and was surprised at how much shit came out of the tubes.

After the kero wash, I turned the tubes upside down and pumped the rod until all the kero was out of the forks and cartridges. That was 10k miles ago and I've had no problems with the forks.

Yeah thats how I did mine

I just checked my manual (as promised months ago, but I got lazy) and the number for 99-03 is 142 MM, or 5.6 IN, not 230 as previously posted.

My 97 manual says 154mm Wonder why the difference

As I remember, there was a difference in the cartridges inside the forks for the 97-98 models.

[Para045]

I just checked my manual (as promised months ago, but I got lazy) and the number for 99-03 is 142 MM, or 5.6 IN, not 230 as previously posted.

My 97 manual says 154mm Wonder why the difference

As I remember, there was a difference in the cartridges inside the forks for the 97-98 models.

Hmmm just read this as I haven't been on here for a week or so and am wondering whether the fact I have replaced my original forks with 04 forks with Ohlins valves, 5w oil and heavier springs that the different oil level (I set it at 154mm) could be contributing to the high speed weave I have been experiencing :icon_think: