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Author Topic: Change clutch fluid -- Honda Goldwing GL1800  (Read 4363 times)

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Offline Postmaster

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Change clutch fluid -- Honda Goldwing GL1800
« on: November 12, 2015, 12:39:21 AM »
Changing the clutch fluid is probably the one maintenance item that is the most neglected item on a motorcycle.    Most manufacturers recommend that the fluid is changed every year. 

This is the procedure for a Honda Goldwing GL 1800, but the general procedure could be applied to any bike with a hydraulic clutch.

Ignore the dirty bike, it gets ridden.

First ensure that you have the correct and enough brake fluid.  The type for your bike is indicated on the reservoir cover.

Remove the chrome lower cowl.  6 allen bolts and it comes right off.

EVAP canister.  This will be removed shortly.

Remove these two hoses on the left side of the EVAP canister.

Remove the two bolts on top of the canister bracket and remove the canister.

Although not necessary, it is much easier to remove the EVAP canister bracket.

Your goal is to have easy access to the bleed valve which is on the clutch slave cylinder. You'll notice that it is behind the EVAP canister bracket.  If you cannot find the bleed valve for your bike, follow the fluid line from the reservoir all the way to the slave cylinder.  There you will find the bleed valve.

Once the EVAP canister bracket is removed, remove the rubber cap on the bleed valve.

Now remove the clutch reservoir cover.  You will notice I have a problem.  Both screws on the cover are stripped.  This was done before I started this time, so I was prepared with new screws and a new reservoir cap.

Really not that big a deal to fix, but take your time.  Drill and a small drill bit that is slightly larger that the screw head.  Go slow and easy.

Brake fluid is very caustic and will strip paint almost instantly.  Before you begin, place a towel underneath the reservoir.

Your goal here is to only drill through the screw HEADS and not the shaft of the screw.  Go slow and check your progress.    Once you are through the screw heads, they will pop off.  The cover will probably remain.  Take a small screwdriver and place it under the edge of the cap and tap it from the bottom.  The cap will pop off, but the threaded shaft will remain.  These are installed will very little force and you should be able to un-screw the remaining shaft with your fingers or grip them with a pair of pliers and simply unscrew them.

On a Goldwing, turn the handlebars to the right until the reservoir is level.  Remove as many of the metal shavings as you possibly can, then remover the white plastic cover, the black rubber diaphragm, and a smaller white plastic piece that floats in the brake fluid.

Shine a light into the fluid in the reservoir and look for any metal shavings.  If you see ANY, remove them.

This brake fluid is past it's usefulness.  Do not rely on the looks of the fluid.  Is been more than a year, it should be changed.  The fluid in the Goldwing was about 18 months old and had 20,000 miles of use.

Do not let this next part worry you.  I do this differently than what the service manual calls for.  The manual indicates to open the bleed valve located on the clutch slave cylinder and pump the clutch lever until no more brake fluid comes out of the bleed valve.  I do not like this method because it allows unwanted air into the system.  Just like brakes, air in the clutch fluid lines or slave cylinder with make your clutch slip, not fully engage or not work at all.

My method and the one I use here, does result in more brake fluid use, but still keeps most of the air out of the lines.

Do not drain the fluid currently in the reservoir.  Top off the reservoir with fluid.

Place a hose over the bleed valve and run it to a suitable container.  You must use clear hose.  When you are bleeding the system and getting rid of the air, you will want to see the air bubbles coming out of the valve.  Loosen the valve, most are 10mm.  DO NOT REMOVE THE VALVE!!!  You will have fluid everywhere and lot of air will be in the system.

My container.

Now you must get the old fluid out of the system.  Do NOT put anything into the reservoir to try and absorb the fluid.  You want this system to be as clean as possible.  The draining and bleeding process is much easier with two people, but it is still easy to do with one person.

Once the bleed valve is open, pump the clutch lever until the reservoir is almost empty.  Do NOT let the reservoir run out of fluid.  If you do, you will introduce air into the system.  Do NOT hold the clutch in while you are filling the reservoir.  If you do, the fluid in the reservoir will continue to drain.

This was in the bottom of my old fluid container.

You will want to continue the drain and fill process for a minimum of six times to ensure that all of the old fluid is out of the system.  Six times is not written anywhere, just my method. 

Close the bleed valve.  Inside the reservoir is a fill line.  Fill with fluid to the fill line.

This is what new clutch fluid looks like.

Keep the fluid handy, you will still need it when you bleed the system.

With the bleed valve closed, pump the clutch lever through it's full range of motion ten times.  On the tenth time, hold the lever in.  If someone is helping you, have them hold the lever in (against the throttle).  If you are working solo, find something to hold the lever in.  If you have several zip ties, use them.  I used a clamp.

With the clutch lever in, loosen the bleed valve, just like before, when the system was drained.  This could take several times depending on how much air is in the system.  Keep an eye on the reservoir to ensure that it does not run dry.  Once you determine that you do not have any air in the system, no more air bubbles when
you open the bleed valve; do it one more time.

Tighten the bleed valve.  DO NOT OVER TIGHTEN!!!.  I can't put enough emphasis on that.  It should be snug.  You can break them off , then you have more problems.  Put the rubber cap back on the bleed valve.

Ensure the reservoir is filled to the fill line and replace the rubber diaphragm.  Not all bikes have the 3 pieces in the reservoir like a Goldwing does.  My KTM only has a rubber diaphragm.  Clean all of the pieces or the ones that you have before you put them back in the reservoir.  Tighten the reservoir cap.  Do not overtighten or you will strip or break the screws.  They should be snug.

New cover and screws.

Now you must test the clutch.

Start the bike in neutral and let it warm up to a normal idle.

This part is very important.  BEFORE you place the bike in gear, ensure that there is nothing in front of you and squeeze the front brake as hard as you can.  Have your thumb over the kill switch.

If you do not have all of the air out of the system, when you place it in gear, it will lurch forward and take off.

With you thumb over the kill switch and the front brake lever pulled all the way in, pull in the clutch (it should feel much better now) and put the bike in first gear.

Some bikes naturally lurch a small bit even if there is no air in the lines.  If yours does now and it did not before, then you probably still have air in the lines.

If no lurching occurred, slowly let off the brake lever and then slowly let off the clutch lever.  If the bike starts to move forward, then all is good.

Use caution when letting out the clutch the first time.  The new fluid more than likely changed where the clutch now engages.

If the bike lurched forward OR when you let out the clutch the bike did not move and there was a delay AFTER you let the clutch all the way, then you have air in the lines.  You must then bleed the system some more until the all of the air is removed.

I know this was a long explanation, but changing the clutch fluid is very necessary and is not that difficult.

Once everything functions properly, put all the body pieces back on and sit back and look at what a good job you have done and the money you saved.

Offline Nice Goat

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Re: Change clutch fluid -- Honda Goldwing GL1800
« Reply #1 on: November 12, 2015, 06:54:14 AM »
Good to see you posting again, dude.  Your tech tips are the best.  ;)
IBA # 63019 / 2017 KTM 350 EXC-F
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