Tyres, Brakes and Suspension » Fork Oil Replacement Process

I'm at 18,000 miles (30,000 kilos) and my manual says it's time I replace my fork oil.

I've not yet cracked open the Haynes (about to) but thought I'd put it out there should anyone have the process well documented.

Special tools? Easy workarounds? Step-by-step?

Even if my initial post here lacks the information others may seek on the topic, anyone with the know-how may as well post it here for the rest of us.

(I myself don't know BMW well enough yet, having only bought this bike this year with 560 miles on it ... it was a BIG riding year!)

Zitat von Robin Dean im Beitrag #1

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... it was a BIG riding year!)

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Yes, you have a real challenge - and it is not unique to the BMW either.

The downside to the upside down forks is the great difficulty in changing the oil.

Do you need special tools? Is the Pope a Catholic? Of course you do; and they are not cheap. The compressor is a large device and it appears to be similar to general fork compressors that are used by other upside down forks.

It is tool 313712 - Pretensioning tool and its extension accessory 31 3 717 and "dog" accessory 31 3 718

The work seems to be done is different on the left and right fork leg for the ESA bikes.

You have to remove the rubber cap up top, disengage the cable.

Your bike (assuming it is on the centre stand) has to be supported.

You then take off the mudguard, and then both of the brake callipers.

You drop the front wheel out.

You then remove the two fork legs.

Access to the pinch bolts in the triple clamps is difficult with the bodywork in place, by the way.

Left Leg

The BMW manual then says you unscrew the top cap, after the fork let is removed. It may be easier to unscrew the cap when the fork leg is clamped by the triple clamp, or perhaps crack it loose there before you drop the leg out.

At that point, and without dropping anything hopefully, you tip the fork upside down and drain the oil

According to the manual, the cap remains attached to the internals.

The fork compressor is then used to compress the spring to pull it away from the bottom of the cap. That should give you access to locknut that has to be held and that allows the cap to be pulled off.

Once the cap and washer are removed, the spring can pull out, followed by a bottom seating washer.

The damper unit is screwed to the bottom of the fork, it sits above the axle hole, and the compressor has to be removed to give you access. Unlike the old Yamahas I had, it seems the damping assembly is "keyed" to the structure of the tube, so you don't need a holder to unscrew the bolt before you remove it and its washer or "sealing ring" (0 ring?)
According to the manual, it is only when you have done this, that you can tip out and drain all of the oil.

You then need to reinstall the damper unit

The left leg takes 304 ml of oil, (part no 83 19 2 408 581) or other suitable oil. There is another measurement with the fork and damper fully compressed, no spring and no spacer, and the oil should be 65 mm below the top. There is a factory dipstick (part no 316 551).

You then refit the bottom washer, and the main spring, both go over the damping assembly. You then reinstall the fork compressor, push down the spring and pull up the damping tube. You then add in the top washer, the locking nut and the cap and when all is properly tight, release the compressor and remove the tool.

If that is now enough, you also have the right leg, but that looks pretty simple. The right leg does not have a compression spring!!!. It does seem to have a rebound spring lower down in the innards of the lower leg.

You unscrew the cap, lower the halves together, and tip out the oil. The cap is still attached.

You need the compressor to hold things in place as you unscrew the cap and the lock nut.

You then pull up and remove a spacer (AKA bushing) a seat (AKA adaptor), a washer, the rebound spring, another washer and a bottom plate.

As with the left side you remove the bolt that holds in the damper unit and its washer (o-ring) and remove the damper. The damper is pumped to remove remaining oil.

You then reinstall the damper and "retract" the damper rod. Now, does "retract" mean to push it down, or pull it up? My guess is that retract means to push it down. This fork holds 682 ml. This means 1 litre of oil split between the two legs, will be pretty much enough.

You prime the damper by pumping it up and down a few times and let it settle until all the bubbles are gone and repeat until there are no more bubbles.

You then measure the level of the oil in the same way as for the left leg, except the measurement on this side is 82 mm.

You replace the bottom washer (aka plate) another washer, the rebound spring, another washer, and the adaptor (looks like a washer) for the bushing.

You then use the compressor to hold everything in place as you put the cap back on.

I suspect I am due for this little task, so I am preparing myself mentally for the task. I don't really want the BMW tool, and if I find a compressor that will work, I will post on it. Failing that, I will just remove the forks and take them to the BMW dealer to have the oil changed.

Zitat von Aussie Import im Beitrag #3

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Yes, you have a real challenge - and it is not unique to the BMW either.

The downside to the upside down forks is the great difficulty in changing the oil.

Do you need special tools? Is the Pope a Catholic? Of course you do; and they are not cheap. The compressor is a large device and it appears to be similar to general fork compressors that are used by other upside down forks.

It is tool 313712 - Pretensioning tool and its extension accessory 31 3 717 and "dog" accessory 31 3 718

The work seems to be done is different on the left and right fork leg for the ESA bikes.

You have to remove the rubber cap up top, disengage the cable.

Your bike (assuming it is on the centre stand) has to be supported.

You then take off the mudguard, and then both of the brake callipers.

You drop the front wheel out.

You then remove the two fork legs.

Access to the pinch bolts in the triple clamps is difficult with the bodywork in place, by the way.

Left Leg

The BMW manual then says you unscrew the top cap, after the fork let is removed. It may be easier to unscrew the cap when the fork leg is clamped by the triple clamp, or perhaps crack it loose there before you drop the leg out.

At that point, and without dropping anything hopefully, you tip the fork upside down and drain the oil

According to the manual, the cap remains attached to the internals.

The fork compressor is then used to compress the spring to pull it away from the bottom of the cap. That should give you access to locknut that has to be held and that allows the cap to be pulled off.

Once the cap and washer are removed, the spring can pull out, followed by a bottom seating washer.

The damper unit is screwed to the bottom of the fork, it sits above the axle hole, and the compressor has to be removed to give you access. Unlike the old Yamahas I had, it seems the damping assembly is "keyed" to the structure of the tube, so you don't need a holder to unscrew the bolt before you remove it and its washer or "sealing ring" (0 ring?)
According to the manual, it is only when you have done this, that you can tip out and drain all of the oil.

You then need to reinstall the damper unit

The left leg takes 304 ml of oil, (part no 83 19 2 408 581) or other suitable oil. There is another measurement with the fork and damper fully compressed, no spring and no spacer, and the oil should be 65 mm below the top. There is a factory dipstick (part no 316 551).

You then refit the bottom washer, and the main spring, both go over the damping assembly. You then reinstall the fork compressor, push down the spring and pull up the damping tube. You then add in the top washer, the locking nut and the cap and when all is properly tight, release the compressor and remove the tool.

If that is now enough, you also have the right leg, but that looks pretty simple. The right leg does not have a compression spring!!!. It does seem to have a rebound spring lower down in the innards of the lower leg.

You unscrew the cap, lower the halves together, and tip out the oil. The cap is still attached.

You need the compressor to hold things in place as you unscrew the cap and the lock nut.

You then pull up and remove a spacer (AKA bushing) a seat (AKA adaptor), a washer, the rebound spring, another washer and a bottom plate.

As with the left side you remove the bolt that holds in the damper unit and its washer (o-ring) and remove the damper. The damper is pumped to remove remaining oil.

You then reinstall the damper and "retract" the damper rod. Now, does "retract" mean to push it down, or pull it up? My guess is that retract means to push it down. This fork holds 682 ml. This means 1 litre of oil split between the two legs, will be pretty much enough.

You prime the damper by pumping it up and down a few times and let it settle until all the bubbles are gone and repeat until there are no more bubbles.

You then measure the level of the oil in the same way as for the left leg, except the measurement on this side is 82 mm.

You replace the bottom washer (aka plate) another washer, the rebound spring, another washer, and the adaptor (looks like a washer) for the bushing.

You then use the compressor to hold everything in place as you put the cap back on.

I suspect I am due for this little task, so I am preparing myself mentally for the task. I don't really want the BMW tool, and if I find a compressor that will work, I will post on it. Failing that, I will just remove the forks and take them to the BMW dealer to have the oil changed.

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Well, it's not my first rodeo with forks in general but yes ... I was concerned that this lovely (yet annoyingly "buy the over-priced special tool") beast would have nanobots and electroencephalograms somewhere.

I'm copying/saving your report for my own reference, Aussie.

THANK you!

Sidebar: for whatever reason, topic auto-subscribe isn't cooperating with me. Anyone know where those settings are? I swear I had them on ... yet didn't receive notification about Aussie's response.

I would like to do mine myself, but buying/fabricating tools that I wouldn't use but a couple of times puts it too far out there. I have a good relationship with my local dealer and I plan to remove them myself and bring them in for service. From previous experience, USD forks are a PITA anyway.

Frank

Zitat von Robin Dean im Beitrag #1

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I'm at 18,000 miles (30,000 kilos) and my manual says it's time I replace my fork oil.

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Zitat von Robin Dean im Beitrag #1

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I'm at 18,000 miles (30,000 kilos) and my manual says it's time I replace my fork oil.

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Zitat von Robin Dean im Beitrag #1

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Special tools?

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I get different answers depending on the dealers. How many hours involve in this oil change ?I used to change the fork oil in my K100RS 86 in less than half an hour. It is amazing how motorcycles have changed over the years to consume so much more time for regular maintenance.

Zitat von albrown im Beitrag #10

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It is amazing how motorcycles have changed over the years to consume so much more time for regular maintenance.

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Zitat von albrown im Beitrag #10

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I get different answers depending on the dealers. How many hours involve in this oil change ?I used to change the fork oil in my K100RS 86 in less than half an hour. It is amazing how motorcycles have changed over the years to consume so much more time for regular maintenance.

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@Lee

I mean, simple is always "gooder". I do have the ESA model. What about you?

... and what was your process? (Like, what am I lookin' at here?)

Or maybe that #20 forum link you referred me to IS your process. Hmmm (duh). Very nice.

Zitat von Robin Dean im Beitrag #13

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@Lee

I mean, simple is always "gooder". I do have the ESA model. What about you?

... and what was your process? (Like, what am I lookin' at here?)

Or maybe that #20 forum link you referred me to IS your process. Hmmm (duh). Very nice.

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Special Tools Continued

I have tried to buy the special tool from BMW, or at least get a price on it. I was told that BMW will not sell special tools to the public.

On Ebay I have found there are two types of special tools.

One looks like the BMW tool (also the Indian one I have seen). It is a long bar / rod fashioned so that it sits parallel with the fork. It has a hook on the bottom, with a peg that fits inside the depression / tube that holds the bolt retaining the damper. This is normally "hidden" by the front axle.

It has a collar that fits around the spring (or the bush on the right side) and engages either with a couple of bolts.

The spring is compressed by winding down on a thread internal to the long bar / rod. This type seems to cost about $170.00 USD

The other type of compressor looks a lot like a large tap wrench. It has two handles attaching to a large pipe or piece of tube. The handles appear to be threaded, and the tool works by positioning the central pipe section over the spring assembly, screwing in the handles until they engage the spring and then pressing down with both your hands to compress the spring.

This type seems to cost about $25 USD

HOWEVER, in the YouTube universe there is strong evidence that NEITHER TOOL is really necessary.

There seems to be enough leverage available to allow you to put a spanner on the locknut (which has to be held to remove the top cap from the damper rod), just by shoving it in above the spring and prying and wiggling it under the lock nut.

Reinstallation seems to be ok without a tool by using a smaller open ended spanner (in the case of the vid, 14 mm / 10 mm) which fits around the damper shaft and can be used to pry the spring down under the bottom of the lock nut.

The YouTube site that I looked at was Delbory's Garage from the UK.