ST1100 Fork Oil change - How to?

Sharpe_93 ST said:
Anyone know if there's a post about "relieving the timing belt cover" ? I'm looking at a fork, clutch, timing belt job myself.
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There is mention of it on here but honestly, its pretty easy to figure out. When you remove the cover, the bolt is going to mark the cover for you :) . Then before you put it back together, cut the section out where the bolt chewed it up on removal and it will slide right in.
 
mcthorogood said:
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.
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I finally took my forks out tonight and I'm a little unsure of how thorough I need to be. The left fork was easy once the cap came off. I just let the spacer fall out and the short tube (about 8 inches long) come out and left the spring and all other parts inside. I pumped all the oil I could out and left it to drain overnight. Do I really need to take it all apart as the oil should run out anyway?

How about the right fork? The damper rod is still in place and the oil seems to be draining fine. I think it would complicate matters to pull it all apart?
 
The correct method for setting the oil level is to put the oil in without the springs in the tubes.

So... if you want to set the level to OEM specs you have to pull the springs.
 
Thanks Mark. In the Haynes Manual it also gives a volume of fork oil to add as well as the one for height of oil in the forks. Can I not just measure the amount of oil in volume and place that in with a syringe or something similar?
Keep in mind this is my first time opening the forks up. Is there a decent link here that explains how to add the oil, measure the height, etc?
 
First a moan: I really, really, really dislike Haynes manuals. I have attempted to use them on VW bugs, Ford Aerostars, Toyota Tercels, ST1100s and ST1300s and find they just don't do as good a job as Clymer or OEM Honda manuals.
Rant over! :)

Here is a youtube video
outube video
that does a good job of showing one of many methods. You can make that tool pretty easily if you have a farm supply place near you that syringe can be found there.

If you have any fluid left in the galleys and use the volume method you'll have too much oil in the fork.

Remember that both methods require you to pump the forks to fill those galleys.
 
ak85lp said:
Can I not just measure the amount of oil in volume and place that in with a syringe or something similar?
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Yes.

The only caveat here is if you don't pump the forks to fully expel all of the original oil, you could overfill them a little if you refill with the volume specified in the manual. If you don't remove the right fork cap you probably won't be able to pump it sufficiently to clear everything, so that's your question you have to guess at, how much oil remained? Also, refilling it through that little cutout in the washer is kind of a pain. So that being said, I'd recommend removing the right cap and give them both a good pumping, but if you really don't want to mess with it I doubt that its really a big deal either way.

As far as replacing the oil by volume or height, to me that's splitting hairs if you still have the stock springs in the forks. If you have aftermarket springs, then the volume requirement has changed, and you should go by height (and note the volume for next time). Its a heavy touring bike, not a racebike, so a little difference in oil level isn't going to make a huge difference in how the bike rides, so don't worry that you have it down to 1ml accuracy.
 
I'll chime in here... Mark's right, the correct method is to measure the suspension fluid level from the top of the compressed fork tube, springs removed, per the Honda ST1100 Service Manual and Common Service Manual. The volume/quantity figure is to help you buy enough fluid before tackling the job. We don't just dump in the engine oil capacity figure when changing oil, do we? :) I've checked/compared a number of times over the years and using the so-called "quantity" method always overfills the forks by a fluid ounce or more. Reducing the air cushion space above the fluid by an inch less than spec may not be a good thing.

Motion Pro sells a DIY fluid level adjustment tool ($$) like any dealer uses but making your own is easy. I've made a couple of them for the STOC loaner Fork Seals R&R Tool Kits: tube stock, PVC hose, and turkey baster or large Farm-N-Fleet syringe. You could go as simple as marking a stick and pouring in fluid until it touches the stick. Suck out excess if need be.

JMHO. Do the job right. Dump and flush x 3 with some cheap ATF fluid to get the crud out. If you have a standard model, use the slider plugs to help get them as clean/empty as possible. When refilling, pump the tubes and damper rod to get rid of the air pockets to insure a correct fluid level.

John

Posted with my iPhone 4S
 
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Thanks everyone good advice. I think I'll do it the right way as I have everything apart anyway to do the timing belt and coolant hoses under the carbs. In the meantime I also found an old link to Mark's Homemade Fork Oil Gauge. It looks pretty easy to fabricate.

https://www.st-owners.com/forums/showthread.php?90708-DIY-Fork-Oil-Gauge

Can anyone tell me the correct oil height from the Honda service manual? I agree Mark, I don't care much for Haynes books but it's all I have for now.
 
John OoSTerhuis said:
I've checked/compared a number of times over the years and using the so-called "quantity" method always overfills the forks by a fluid ounce or more. Reducing the air cushion space above the fluid by an inch less than spec may not be a good thing.
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Interesting, I'll have to check that measurement myself next time. From a practical standpoint I've never used any other method besides the quantity method for 35 years and 450k miles and typically get 40-50k miles per set of fork seals. So it would seem that if I am reducing the air space it doesn't affect the seals. It may change the ride characteristics a bit, but I have no idea by how much or if it would even be noticeable on a bike like the ST.
 
Seems like if using the 'quantity' method and not doing a complete disassembly, the way to do it would be to measure what came out, and put that amount back in, rather than using a published amount.
 
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dwalby said:
Interesting, I'll have to check that measurement myself next time. From a practical standpoint I've never used any other method besides the quantity method for 35 years and 450k miles and typically get 40-50k miles per set of fork seals. So it would seem that if I am reducing the air space it doesn't affect the seals. It may change the ride characteristics a bit, but I have no idea by how much or if it would even be noticeable on a bike like the ST
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When I fitted the hyperpro fork springs they said to leave an air gap of 150mm,I just used a strip of cardboard with a mark on it and filled the oil till it touched the bottom of the cardboard,
left fork took 450ml,right fork took 550 ml,the left fork on my 01 abs has the big damper rod in it so I suppose that's why it needs less oil.I used aftermarket 'sifam' seals so I'll see how long they last,seemed a good tight fit.
I used motul synthetic 10 wt oil.
 
DeanR said:
Seems like if using the 'quantity' method and not doing a complete disassembly, the way to do it would be to measure what came out, and put that amount back in, rather than using a published amount.
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Dean, how do you know the spec'd level was correct to start with?

As to the short-cut quantity method vs the manual's level method comparo, that's easy to do. Pour in the measured 'capacity' quantity and then measure how much you suck out to achieve the spec'd level. BTDTx4

Look, if I'm going to change my fork oil I'm going to pull the forks so I can get a thorough flush/clean-out of the old oil. If I'm going to pull the forks I'm going to measure the new oil the way the manual and any reputable shop would.

Usually when the quantity method is brought up, someone is trying to rationalize not pulling the forks and/or removing the springs, and are trying to justify it/get acceptance/approval.

FWIW YMMV Whatever floats yer boat.

John
 
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John OoSTerhuis said:
Whatever floats yer boat
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I agree John! The right way is the right way for a reason.

Having said that, I 'shortcutted' this last time. Pulled the forks, didn't want to take apart the pesky right one, so I just did the measure thing on that one. (under the assumption that the level had been correct). Plus, this was not done on the bike I'm using. It was done on the one that sits in the garage at present.
 
I do not have the shop manual yet. Will some one tell me about how often it should be changed.
My 02 with 40,000 has never been done and I have tires arriving this week.
 
Dunten said:
I do not have the shop manual yet. Will some one tell me about how often it should be changed.
My 02 with 40,000 has never been done and I have tires arriving this week.
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The ST shop manual doesn't specify, it just mentions inspect the suspension at periodic intervals and refer to the common service manual. I change mine with every front tire replacement, because I've already got the front wheel and calipers off, so pulling the forks is only a few more quick steps. And I can always remember when was the last time I changed it without having to write it down. On the ST the oil looks fairly dirty at those intervals, so I don't think that's too often. If you want to stretch it out a bit longer I wouldn't go past 20k miles. Cleaner fork oil seems to get you longer service out of fork seals.
 
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