ST1100 (non ABS) Fork leaking oil

[krist0ph3r]

Exactly a year since I started riding my 2001 ST1100 (non ABS), my wife and I were on a ride out for the weekend, when suddenly the front end started giving a light "thunk-thunk" sound that was too loud to ignore. Tried wheeling it backward and forward, could not see anything visibly touching anything to cause the sound, and at that speed it sounded more like a brushing than a hitting sound. Was about 40 miles from home when the sound started, so decided to ride home really slowly and hope I got there without mishap.

The sound was periodic with wheel rotation, and got louder and more noticeable (physically) about a couple of miles in. At one point it started sounding like a "whack-whack" sound, and then before I could react it started shaking the handle violently as of something was hitting something physically (but the sound was not metallic). And then... silence. The sound and vibes stopped, and I coasted to a stop a few hundred metres ahead. The only sign that something had gone terribly wrong was oil spurting downward from bottom end of the left fork/left brake calipers (it was hard to tell as both were splattered with fresh oil). I tried walking back to spot anything that might have fallen off, but I didn't spot anything (or maybe I didn't walk far enough). 5 minutes later, oil was still dripping, but at a slower rate. Didn't wait longer as it was getting dark, rode home slowly, not using the front brakes (in case it was brake fluid that was leaking - but the level in the reservoir didn't seem to be going down).

Back home, this is what the left fork looked like:



Waited till today morning, so that some of the oil could dry and I could possibly locate the problem better:



Took it to the mechanic who had last done my brakes a few months ago, and he confirmed it's fork oil that was leaking. He said it wouldn't be a quick job, and checked online for the parts that could be at fault (I didn't check which site, but it wasn't Honda), and they mostly showed unavailable or on backorder. Mechanic's verdict: it might be better to salvage parts off another ST1100 if possible, else I'm looking at my wheels sitting in his garage for a couple of weeks while he identifies the problem, gets parts shipped and fits them - a situation I'd rather avoid.

Some more observations, in case they help:

1. The brakes were serviced in mid January as they were binding. After the service, things were much better than before, but when wheeling the bike backward to park, it felt like there was more resistance than before - I wasn't sure if that was true or my imagination, as I started parking in reverse so I can roll out forward, after the brake binding incident. But last night, the bike was absolutely free when rolling backward - I was even able to wheel backward while astride, while it normally required me to get off and use the parking handle and still getting breathless in the process.
2. I noticed over the last few weeks that there was a slight squeaking sound (in time with wheel rotation) when I'd start moving after a few days of the bike sitting still. I put it down to the brakes not having retracted smoothly and taking some time to get pushed back into position when rolling. The squeaking died after a minute or so which seemed to fit my theory.
3. I noticed over the last couple of rides that the squeaking sound was louder when turning. Again no squeaking after a minute or so of riding.
4. Parked last night after the incident, I checked that nothing from the fork was in contact with the wheel/disc rotor.
5. Oil still dripping over 18 hours later, although much slower.
6. I collected a couple of drops of oil last night to check the colour. Seemed clear, slight red tint:
   

So my questions are:

1. Anything I should do right now to prevent anything going further wrong? I'm not planing to ride again until fixed, unless it's to the mechanic.
2. What could have gone wrong?
3. Anything more I can do to investigate (visually/without doing anything to make it impossible to ride to the mechanic)
4. Best reference for what parts would be involved? (I have the Honda workshop manual and the Haynes one, although Haynes says '90 to '97, I think it still applies)
5. I have a friend who knows someone who deals in scrapyard stuff, is that a worthwhile direction to pursue for this problem?
6. I have a decent set of tools, but don't have much experience - should I attempt the job myself or trust the mechanic with my bike (and my money )
7. If I choose to do it myself, what consumables would I need to replace (besides the parts etc in (3))? Do I need specialized tools for something like this?

I'm probably going to have more questions as this progresses

 

[Upt' North]

It's the anti dive.
Parts are available from CMS NL as far as I'm aware, it's really not a big deal. There's a schematic on the site.
Chill friend, order the bits and get it sorted.
Plus you might need a new mechanic, a decent one would have that apart in ten minutes, diagnosed where the leak was coming from, probably the piston seal and ordered the bits.
Upt'North.

 

[Upt' North]

P.S. It needs a clean .

 

[Larry Fine]

It's the anti-dive mechanism gasket. The caliper pushes in on that little piston when you brake, and stiffens up the suspension.

 

[Upt' North]

 

[dwalby]

Looking at the picture you appear to be missing one of the bolts that holds the brake rotor to the wheel, which may have something to do with the knocking sound you hear occasionally. Or, the whack-whack followed by silence may have been the missing bolt finally falling out of the wheel, hard to say.

+1 on getting a new mechanic, all the parts around the anti-dive are available on the Honda fiche, and you can replace them all with the fork still on the bike so its not much work at all if you know what you're doing.

 

[John OoSTerhuis]

+3 Your “mechanic” is an idiot! Missing rotor bolt. Anti-dive failed.

What do you mean by ‘brakes binding“ and what did the “mechanic” say he did to “fix” that....??!!

John
PS - pull the caliper, the rotor was banging on something!

 

[Bush]

Definitely a rotor bolt missing and that is not an OEM rotor. All those bolts need checking. The bolt probably caused the damage to the anti dive as it swiped past until it either fell out or was sheared off. Sort of looks like it was sheared off. That will pose a problem with the wheel too.

If that "mechanic" messed with the rotors while doing your brakes recently, he needs to eat this repair, but I'd be leery of him touching the bike though.

 

[The Cheese]

Do not ride that bike! First thing I noticed was a missing rotor bolt on what looks like cheap Chinese rotors. Even without all that the tires and rotors are coated in fork oil.

You need a new mechanic. DO NOT go back to whoever did those brakes. The same one looked at it like it sits and said nothing about the glaring obvious dangerous situation.

I mean this as nice as I can. Maybe you need a sports car instead of a bike. Ignoring signs of failure on a bike could get you killed. Least in a car you get airbags.

 

[ST Gui]

Maybe you need a sports car instead of a bike.

Or maybe he just needs some help and support from knowledgable members. He's already getting a lot of valuable information especially regarding the mechanic.

The mech may be shady or shade tree or completely clueless about an ST of any flavor. Rather than consider the explanation it would do the OP well to learn how to handle this himself if he has the tools/space/desire to do so. I don't know about this mech but it seems a lot of them - indie or Honda - have little to no experience with an ST. Most need to be at least as long in the tooth as the ST to have even seen one.

Not to pile on but the bike needed a clean even before this mishap.

 

[krist0ph3r]

Thanks everyone for the advice... It does seem like the mechanic has no idea about STs, as he wasn't sure what the parts involved are called. His previous brake job got myself out of the immediate problem (brakes sticking so bad I couldn't even wheel it a couple of inches), but the problem was back within weeks - he maintained that brakes need regular freeing up or they tend to stick, and that he does his own bikes' brakes monthly. Seemed odd to me, having never seen this on any of my motorcycles ridden for over 100k miles over 12 years (albeit in India, so no salt/grit but a lot more dirt, higher temperatures and near 100% humidity). Maybe that's cos he's trying to give himself business... or maybe he's simply incompetent. His explanation of what he did then: took off front and rear calipers, removed the pads and cleaned them (they didn't need replacement), replaced the dust seals, cleaned the pistons, replaced all fluids. I was present as he did the rear disassembly and cleaning but then had to race off to work.

Back to the current problem: the rotor bolt was definitely not missing earlier. It could be the cause of the problem! (Also, guess I'm lucky that missing bolt happened to be in the photo - will look over for other signs of damage as well). As for the rotors, the previous owner said (and I believe) he replaced all three shortly before putting it up for sale - I checked it them the time of purchase and they had not even the slightest sign of wear, he used to service all his motorcycles himself (he owned 3 at the time) and he claimed he purchased his parts online from Honda's site - any specific way to check if it's original? And does it need replacing if it's thick enough and not warped after 5k miles of use? For the rest of the parts, given that this sounds like some sort of impact caused it, sounds like I should replace the entire anti-dive assembly, correct? Anything else I need to check (besides visual inspection for scrapes/dents/any other sort of damage on the brake assembly and fork)?

And to be doubly sure: the parts involved are the ones highlighted in green below?



ps: regarding the much required cleaning job, is it just the fresh oil splatter? Granted, I've not maintained the bike to a spotless standard, but I have been giving it the soap and water treatment fairly regularly - especially focusing on the brake bits as they always seemed less than perfect to me since January. Cleaning before the ride to the mechanic today would have been pointless as there was fresh oil dripping at a steady rate as I watched. Definitely going to make sure all traces of oil are off before I'm on the road again.

 

[The Cheese]

I'm all for help and support. Really. But, it's my gut feeling, some may not be well suited for motorcycle maintenance. OP ignored signs that something was wrong and still rode it. Took pics and didn't notice the obvious broken bolt. They thought it's fine to ride it in that state. I can't teach common sense over the internet.

This may be too difficult to guide you without being in person. You should find a local and befriend them.

I tired to be polite about telling OP that biking may not be for them. And suggested a similar activity. It truly is with love.

 

[John OoSTerhuis]

I won’t comment on the “mechanic’s” BS.

Your calipers must be rebuilt. Disassembled. New seals (dust AND FLUID!, pistons polished (or replaced), complete fluid change, oil-soaked pads replaced, and rotors fixed and acetoned.

Take the anti-dive apart and replace parts as needed.

 

[dwalby]

As for the rotors, the previous owner said (and I believe) he replaced all three shortly before putting it up for sale - I checked it them the time of purchase and they had not even the slightest sign of wear, he used to service all his motorcycles himself (he owned 3 at the time) and he claimed he purchased his parts online from Honda's site - any specific way to check if it's original?

the rotors are definitely not original, they're aftermarket of some kind but I can't say what brand. Also, the rotor tab with the missing bolt may have a crack in it, hard to say for sure from the picture, but it looks like a crack going from the bolt hole out to the edge of the tab at 9 o'clock, so take a closer look at that. It may be just a stream of dirty oil that looks like a crack. You'll be shocked at the price of motorcycle brake rotors, so be prepared if you need to replace the rotor.

John's comment above about cleaning your calipers is in regard to your problem with the brakes sticking, caused by the pistons being dirty and not retracting properly from the rotor after releasing the brake lever.

If the brake pads have absorbed fork oil, then you'll need to replace them, you won't be able to clean the oil off well enough to re-use them. The rotors can be cleaned with a solvent like acetone (or spray carb cleaner), that doesn't leave any residual on the metal, but if that tab is cracked you need to address that as well.

Welcome to the world of motorcycle maintenance, if you're not mechanically inclined you'll end up spending a lot of money on other people's labor that isn't really all that great, as you have already experienced, so learning how to do these things yourself will help a lot in the long run on a bike of this age.

 

[GGely]

+1 on pretty much everything above. Here’s my $0.02 worth of new material:

For what I think the next visit to a mechanic would cost, you can probably outfit yourself with all the tools you need to solve a lot of the issues with your bike. With this forum, the old archive and a little thought, not much on these bikes can‘t be repaired at home.

However, the mindset to do things like assess the condition of your motorcycle before and after riding can’t be forced on you. And this is where The Cheese’s earlier post comes into play.

Please honestly assess your skills and psychological makeup. As a hive, we will offer you best practices for pretty much anything to do with motorcycling but you have to bring the willingness to accept the advice and the skills, mental and physical, to do so.

Case in point, if you don’t follow a pre-ride checklist or process, get one and implement it religiously. Without fail. And make it detailed. And when even the smallest thing looks off, park the bike till you can get it sorted. This kind of stuff kills people every day and, in your case, I bet we’re all in agreement that Only blind luck kept you in one piece.

This isn’t for everyone so if your self assessment has you in a Mazda MX5 or a Sunbeam, so be it. There’s no shortage of great roads, cars and people in your neck of the woods to enjoy.

If you decide to stay on two wheels, that’s great too. The more the merrier. Just know that we care enough about the sport and each other to say, “Hey! Take up knitting, Jack!”.

Good luck!

 

[krist0ph3r]

Thanks everyone, I now realize how close a call it was, and I guess I need to add a bit of common-sense to Honda's pre-ride checklist. All the motorcycles I've owned prior to this one (in India) were much newer (oldest being barely 8 years old at the time I sold it), and benefited from a reliable mechanic taking care of almost everything for me - all my knowledge of maintaining motorcycles has been purely academic and observational until a year ago. Lesson learned.

The rotor bolt does seem to be what caused the whole incident to begin with.





I did a bit of cleanup, since the fork has stopped dripping oil, and inspected further for damage. It seems the bolt hit these two spots when it got loose:





I'm not sure what else I can check before I start taking things apart.

Also, I've noticed this bit has nothing attached to it, but that seems to be so in all the photos of ST1100s I've seen as well, so I have no idea if that's damaged as well:



Given that the fork seems to have taken a pretty bad hit, does this still seem like a job for a first-timer? My other option would be to check with the riding school I went to for my license and have them refer me someone reliable to do the job.

 

[dwalby]

Given that the fork seems to have taken a pretty bad hit, does this still seem like a job for a first-timer?

probably, everybody has to start somewhere. Take your time, clean everything up, remove the caliper from the fork leg, and come back for more advice after you have the anti-dive parts off the fork leg. But, remember to put a drain pan under the fork leg when removing the anti-dive, because the remaining fork oil will drain out when you remove it. And, to avoid having the oil spray across the room, you'll need to jack up the front end to take the weight off the front wheel.

Take some pictures if you have any doubts as you're removing parts. I think John has first-hand experience with replacing the anti-dive parts, I do not. Also, don't go cheap on tools, the first time you round off a bolt head with a cheap tool you'll understand why. You don't need to buy professional level tools, just don't buy the cheapest Chinese junk tools you can find, they're nothing but trouble in the long run.

 

[Larry Fine]

The leak may have stopped because the fork leg is empty.

 

[TerryS]

The empty socket on the brake hanger is for a missing bracket that is meant to support the speedo cable. It was missing on my ST as well, and didn't seem to be terribly critical. I've never been able to find it on the parts fiche.

 

[dwalby]

The empty socket on the brake hanger is for a missing bracket that is meant to support the speedo cable. It was missing on my ST as well, and didn't seem to be terribly critical. I've never been able to find it on the parts fiche.

I'm the original owner on mine, and that threaded hole is there on mine too, with nothing attached to it.

maybe that same caliper was used on another model, and had something attached to it, I dunno, but it serves no purpose on the ST1100.