ST1100 Fork Oil change - How to?

I have been trying to find some good advice on how to change the fork oil on an ST1100. My Haynes manual lists the procedure as having to remove the forks but I have seen other posts where people say you can just pump the forks and bleed the old oil out the bottom?

I have never looked at mine (2001 with 130,000 kms on it)

If someone can point me to a good page that would be great.
I also do not have the Honda Service manual for this bike other than the Haynes one.

Pumping will get most of it out, but if you want to start with a nice clean system when done,,,they need to come out and come apart. Just depends how thorough a job you want to do.
You have to take them apart to inspect the bushings anyway, so I always take them down.

Check and see if you have a little screw on the outside of the fork near the bottom. If you do you can remove it and pump the front end to empty the oil all over the area right and left of the bike.
BTDT... didn't like the mess... put a rag over the bottom to block the *long* stream of oil.

If you want to really change all the oil, maybe because it has been used just a tad longer than the recommendation by mother Honda(!), you will need to pull the forks out of the triple tree and drain them upside down over night.

You also might want to really think through when you should loosen the fork caps as after the forks are off the bike it is *really* hard to do. BTDT too!

Good luck!

P.S.
If you bottom out the front end *ever* it might be a good time upgrade your fork springs too!

If you want to do it right....pull the forks! It's really not that hard to do or that much extra work!

Ok, sounds like that is the step. Is there a good article somewhere with decent pictures?

I always thought one side was a cartridge without a spring. Guess I better read the service manual to be sure. Definitely agree with pulling the forks to dump out particles at the bottom in the oil. If the bike can be properly supported /stabilized it is not hard to do. Disassembly is even better, so you can inspect components for wear, but the last one I disassembled was a complex XR650r fork and it got costly due to a mistake I made

I used the manual and didn't have much of a problem...
It helps to have 3 or 4 hands available in a couple of spots when disassembling and at reassembly...

I just changed the fork oil in my 1999 ST1100. You need a 17 mm allen wrench to loosen the caps on the top; I ended up welding two nuts together and using a wrench. Loosen the upper pinch bolts before loosening the caps a smidge. Then just loosen the bottom forks and slip them out. I flushed my forks several times with Marvel Mystery Oil, before filling them to the correct level. I used a turkey baster with a short length of tubing to adjust the oil levels. I used a coat hanger and an extra pair of hands to assemble the right cartridge fork. One of the assembled forks leaked like a sieve, so I took the dust seal off and used 35mm film to remove the dirt from the oil seal. It worked like a charm. I left the OEM fork guards off and replaced them with NOJ fork guards. Be sure to order new o-rings and while you're in there you might as well rebuild the anti-dive piston on the left fork.

DaveM said:

If you want to do it right....pull the forks! It's really not that hard to do or that much extra work!

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I typically do mine at each front tire change. Since pulling the front wheel off is the first step, you're already half-way there. And the ST1100 seems to get the fork oil dirty fast, 10k miles or so isn't too frequent of a change interval and I always know when I changed it last.

mcthorogood said:

I used a coat hanger and an extra pair of hands to assemble the right cartridge fork.

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Could you elaborate on this a bit? I hesitate to do my fork oil because I find the two forks being different to be confusing. I seem to think that I will not have a correct tool to do one or the other. Probably the right. Removing the forks is easy. It's what to do after the cap is off that I'm not confident about.

When you have gotten the forks off, the first thing to do is to remove the fork caps, carefully they're spring loaded. The left fork cap comes right off, then you take out the spacer, washer and spring, turn upside down to drain the oil. The right side fork cap is attached to the plunger rod for the cartridge and has to be unscrewed from the cap. Once the right side cap is removed the plunger rod will slowly fall down into the fork. You remove the spring, spacer and washer same as the left side, remembering the sequence they go back. To drain all the oil from the left fork, you pump the fork. To drain the right fork, collapse the fork and pump the plunger rod. The assembly of the right fork is complicated by the rod which falls down into the fork. The extra pair of hands holds the rod up with a coat hanger, while you put the spring, washer(s) and spacer back. You'll need to compress the spring while you thread and tighten the cap onto the rod. I changed my oil at 63,000 miles and I still don't believe the amount of crap in it. Remember to clean the outside of the forks well before disassembly, otherwise dirt might get into the oil seal, DAMHIK.

Thanks for that explanation. Much clearer now.

So no need of any special tool (other than a trusty coat hanger) for that pesky right side?

Mark said:

Check and see if you have a little screw on the outside of the fork near the bottom. If you do you can remove it and pump the front end to empty the oil all over the area right and left of the bike.
BTDT... didn't like the mess... put a rag over the bottom to block the *long* stream of oil.

If you want to really change all the oil, maybe because it has been used just a tad longer than the recommendation by mother Honda(!), you will need to pull the forks out of the triple tree and drain them upside down over night.

You also might want to really think through when you should loosen the fork caps as after the forks are off the bike it is *really* hard to do. BTDT too!

Good luck!

P.S.
If you bottom out the front end *ever* it might be a good time upgrade your fork springs too!

Click to expand...

Hi Mark, would you say the same applies if you bottom out the rear end ever? my bike was bottoming out two up last week,so I put the shock up to position 5 and turmed the preload up full, the bike still feels a bit lower than before,not too sure though as I have been riding my vfr alot lately.

DeanR said:

So no need of any special tool (other than a trusty coat hanger) for that pesky right side?

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Unless you call a 17mm hex wrench a special tool. I couldn't find one around my small town, so I had to fabricate one.

mcthorogood said:

Unless you call a 17mm hex wrench a special tool. I couldn't find one around my small town, so I had to fabricate one.

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17mm hex no problem. Just concerned with how to handle that rod to cap connection on the right fork. Do you remove the cap, let the rod fall, and then use the coat hanger to retrieve it. Or should it not be allowed to fall to begin with. I remember older posts about this that included some pics of a tool. Home made and/or in the kit that floats around.
Maybe all this will be obvious once the cap is loosened.

DeanR said:

Just concerned with how to handle that rod to cap connection on the right fork.

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When you unscrew the cap for the right fork, it will not spring out like the left fork. The right fork spring is compressed by the rod and the cap. You'll have to push the spring down while holding the cap in order to remove the cap from the damper rod. Once the cap is removed the rod will slowly settle into the shock tube. With the shock held upside down, you use the hanger to pump the fluid out of the cartridge.

mcthorogood said:

When you unscrew the cap for the right fork, it will not spring out like the left fork. The right fork spring is compressed by the rod and the cap. You'll have to push the spring down while holding the cap in order to remove the cap from the damper rod. Once the cap is removed the rod will slowly settle into the shock tube. With the shock held upside down, you use the hanger to pump the fluid out of the cartridge.

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This is just a bit incorrect, but the basic idea is correct. The spring is compressed by a preload spacer, held down with a dished washer, held in place by a nut, which threads onto the end of the damper rod. You can remove the fork cap simply by holding the nut with an open end wrench (14mm IIRC) and removing the cap with the 17mm allen tool. Nothing moves when the cap is removed. Then, when you compress the spring you can then pull the washer out from under the nut, as it has a big groove cut out of it for that purpose. Doing that removes all the tension on the spring. You may want to back the nut off a little to make removing the clip a bit easier, but the rod will try to rotate so you may not get far with that. Once you get the clip off, then the rod will sink into the tube, but all is not lost. Remove the spring and compress the upper tube into the lower tube and you can easily pump the rod and eventually extend it back up to its intended position.

For re-assembly the tricky part is having enough hands to 1) hold the rod in its full up position, 2) compress the spring in order to get the clip back into position, 3) put the clip back in place. I think the last time I did it I used a strong magnetic pickup tool to hold the rod and grasped that with 2 fingers. I compressed the spring with my other hand, and then put the clip back into place with the other 2 fingers on the magnet hand. Having a second helper is easier still.

Upon reassembly you want 10.5mm of threads extending above the top surface of the nut, which is where you reattach the fork cap. Hold the top nut with the 14mm wrench, and retighten the cap to the top of the rod. Then pull the top slider tube back up to the cap and reattach the cap into the top slider tube.

broc11 said:

Hi Mark, would you say the same applies if you bottom out the rear end ever? my bike was bottoming out two up last week,so I put the shock up to position 5 and turmed the preload up full, the bike still feels a bit lower than before,not too sure though as I have been riding my vfr alot lately.

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If you bottom out either the spring isn't strong enough or the shock is done.
I tried adjusting mine before replacing it and the rear end felt 'squirelly' (technical term, I know!). I replaced it with a HyperPro ($$$) and love the feel.

Thanks, I am considering getting the oem rear shock replacement or maybe a hagon, she is fine riding solo but two up I can tell the spring/shock are shot.
what is the right fork oil to use? 10 w? I am changing the fork oil in my vfr with 10 weight so I wonder would the same fork oil do the st1100. thanks

Well, if one has a standard (non ABS) or a pre '95 ABS-I the procedure of fork oil replacement it eased by the drain plugs provided in the fork bottoms, thus no removal required ;-) On all post '96 ABS-II models however removal is mandatory. I also wash out all them deposits with a good flush with brake cleaner and let it vent out well before filling the new fork oil. On I high mileage bike I would also strongly recommend a full overhaul, consisting in replacement of the glider bushings and installation of new fork seals.