Coolant leak

Step-by-step tutorials on how to maintain and fix your GL1800
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Posts: 48
Joined: Sat Jun 30, 2012 7:01 pm
Location: Perth, Western Australia, Australia
Motorcycle: 2004 Gl1800
2019 CB500X

Coolant leak

Post by collinsa »

I had a minor coolant leak traced to a loose hose clamp on the radiator but the smell of coolant is always present so at 158km I am going to strip down replace all hoses and water pump/thermostat etc. because if I am going to this trouble to strip down the new parts are to save finding another problem later on. Full set of hoses + water pump is about $400 so relatively cheaper than hours of repeating a strip down.
Have a full Honda service manual and intend to tag and number electrical plug and socket pairs plus photograph sections as I go.

I have had the fairing off before to trace the first leak and I have totally stripped all plastic from a GL1800 for a mate to have repainted so I have no issues with that

Any other suggestions or things I should be aware of?

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Steve F
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Joined: Thu Apr 07, 2011 8:25 pm
Location: Grand Canyon State!
Motorcycle: 1976 Honda CB750F Cafe' (sold :>( )
'03 GL1800

Re: Coolant leak

Post by Steve F »

Keep us updated on the steps you went through, take some pic's and write down things and report back how long it took, the problems you ran into and how you got around them. That would be your assignment :D
"To ride is the reason, the destination's the excuse."
Posts: 48
Joined: Sat Jun 30, 2012 7:01 pm
Location: Perth, Western Australia, Australia
Motorcycle: 2004 Gl1800
2019 CB500X

Re: Coolant leak

Post by collinsa »

Wing Cooling System repairs.

The manual is of great help in guiding the process of getting into the innards of the bikes
To make it easier to follow the sequence of dismantling I read through the manual, printed out the relevant sections and put them in order of action so it was easy to turn pages and immediately access the info. Having previously completed stripped all plastic from a mates wing for repainting I was reasonably familiar with most of the fastenings.

I set up a long trestle in the garage and a long drop sheet in the lounge room. (I have a very understanding wife)
The seat, side panels, dashboard, main centre console, screen and all associated plastic were lined up in the lounge floor in order of dismantling.

The centre console is not that difficult to remove it just takes patience

All the fastenings went into individual labelled containers except for the fastening that hold the nose cone and screen in place.

Nose panels and screen
Previous experience had shown me that the fasteners are of different sizes and have a variety of shanks to suit a particular location for each.
I used a piece of cardboard and punched holes to match the fastener locations and attached them as they were removed from the bike (Photo)

TIP – when removing the main nose piece stuff some rag into the gap under the bolt located just inside the mirror as it is very fiddly to remove and replace these and the rag catches the bolt, washer and grommet should you drop it.
Not so much of a problem dismantling as you will eventually find it – the fun will start if you drop it on reassembly. (photo)

There are 8 cables connected to the front fairing
4x headlight – 2 hi 2x low beam
2x headlight adjuster motors
1x indicator located just below the RH mirror
1x Bank angle sensor (green 3P plug) –

Do not forget to plug this in otherwise the engine will not start not matter what you do.

Also there are 2x plastic grommets that hold the upper LH & RH air vents to the top frame on the dash side of the bike – these are a bit difficult to see but are just inside the fairing in line with the mirrors and underneath the speakers

TIP to avoid problems and the damage to the air vent tubes as above remove the air vents from the centre console before reinstalling the console. This will make the job much easier and the vents simply click into place when the console is correctly located on the bike.
To get to where I thought the leak was located you have to remove the module on top of the filter box. Most of these plugs are specific to their sockets so I did not bother to label these but I labelled or colour coded those located in plastic socks down both sides of the frame – matching labels on plug & socket.

You will also find an empty socket – I labelled this “empty” so as to avoid wasting time trying to find a non-existent plug as I did the first time I removed and replaced the console.

Air filter cover, air filter followed by 2x air inlet cones – note they are LH and RH so do not mix up.
Lift air box and disconnect 4x pipes – 2x come from the crankcase breather on top of the engine,

The 3rd is a clear plastic tube that goes from LH front of airbox, down the front LH side of the engine into the LH engine cover
This tube catches excess oil from the airbox and should be checked and emptied every time a service is done. If you find more than a few ml of oil in this tube check your oil levels as you may have too much oil in the sump.

The 4th hose is attached to the RH front corner and fortunately there is enough slack in the hose the allow you to lift the air box and get at the spring clip

cover the top of the air intakes with heavy cloth to prevent dirt and other unwanted items getting into the inlets

Fuel tank
I discovered that they glue and clamp the fuel line in place when installed in the factory. You will need to cut the pipe, pry off the clamp and slice hose lengthwise into small strips then scrape away the glue and pipe before using emery to clean up the inlet pipe.
This cannot be detached from the tank pump outlet unless you remove the entire top fuel tank cover – I know because I tried
The fuel line goes to the RH injector rail fitting and this can be detached - cut off the glued line, polish up, fit new fuel line and replace – be careful not to loose the “O” ring on the inlet pipe and cover the inlet with rag to avoid dirt getting into the injector rail.
I used double clamps on the fuel line at each end to avoid leaks and provide back up should one clamp fail.

If you are going to do this job it is best if the tank is as empty as possible to make it easier to lift and manipulate out of the frame
You will need to remove the battery and battery box.
Remove fasteners from tank, lift at front and then gently rotate clockwise to release rear LH corner – tank will then come out of the frame.
You will see the rather large protrusion on the RH rear of the tank – this fits through the frame and I assume is to provide an additional litre or so of capacity
Replacement is the reverse but needs gentle but firm persuasion for the LH rear of the tank to rotate anti-clockwise and fit back into place. It is a fairly tight fit.

The coolant was leaking from the clamps on the “Y piece” in the line that connects the LH & RH radiators to the water pump and you could see the trail it had left down the engine and off the side. I ordered a new Y piece as insurance in case the original broke on removal
At this stage I was still not sure if the water pump might also be leaking

I had previously decided that as the bike had done 160k, and as it takes so much time to get to the water pump or any of the major hoses etc, that I was going to replace the complete pump (with thermostat) and as many hoses as I could reach.

To get to the water pump you have to remove the;
Alternator (LH side 3x bolts, 1x main wire and 1x plug) – relatively easy

Rear brake master cylinder- not so easy. I removed the brake pedal, moved the adjuster screws upwards as far as possible and push the pedal shaft through inside the frame. Takes a bit of wangling but eventually it will come out – putting it back was the fun bit!

Reverse return spring – you will need to use a long nosed socket and various extensions to fit through the frame from the rear of the cross member and a pair of multi-grips to hold the spring while you undo this bolt that is located inside the spring

The cables can be left attached to the spring assembly

Reverse spring shaft

Starter motor – 1x wire and 3x bolts – again relatively easy

Water pump – top hose and some rather awkwardly located bolts –
The pump turned out to be in top condition with no evidence of leaking from the seal however as I had already purchased a new pump this was fitted instead.
Remember to fit a new “O” ring to the pump body to seal on the engine block.
The water pump is driven by a shaft with a flexible fitting – to reinstall you have to rotate the crankshaft via the rear wheels to get the female slot on the drive shaft inside the engine into the vertical position otherwise the male key on the pump shaft keeps dropping down and out of place (see photo in next post)

Water pump key that fits into drive shaft inside the engine – it will only locate into slot when vertical (see photo in next post)

Replaced alternator and starter motor.
The fun then came with reinstalling the rear brake master cylinder – much muttering and cursing in getting the brake pedal shaft back through the frame from the inside but eventually it was in place.

TIP make sure you clean the inside section of the frame so sand and grit are not picked up in the grease and pushed into the shaft hole during reinstallation

TIP - before attaching the banjo bolt at the top of the master cylinder use a syringe or other to fill the cylinder with brake fluid - this will make the job of bleeding so much easier.

To replace the bottom hoses I removed, cleaned and checked the two radiators and as the picture shows the LH one had damage from contact with the fan.
(see photo in next post)

A visual check showed clearance was normal and the fan showed no evidence of continuous rubbing
My bike has never been involved in a serious accident and the only occasion I can remember having a hard fall was on a wet dirt driveway when the front wheel suddenly slipped into the LH rut spinning the handlebars hard left while the rear wheel dropped deeper into a hole in the RH rut. This span the bike 90 degrees to the left and unceremoniously dumped me on the ground. The crash bars protected the fairing and all I can think of is that the impact pushed the fan into the radiator but how I do not know. Interestingly, given the damage, the radiator was not leaking but the tubes were crushed in the contact area and I am sure would have eventually broken through at the most inconvenient time and location.

As there was no LH radiator in Australia or the USA this resulted in delays getting one from Japan via USA
It was quicker and cheaper for me to order the radiator from USA than it was from my local dealer to source ex Japan.
I highly recommend Honda Directline parts in OHIO, as their service is excellent - (thanks Daniel)

I had previously decided to use the time while the bike was off the road to remove and repaint the front engine cover. This was completed, but for some reason I have still yet to find, one of the fingers on the pulse generator rotor was bent. (see photo in next post)

The contact area is on the back of the finger. This disaster was discovered after I tried unsuccessfully to start the bike – no spark
More delays while a new rotor and gasket was sourced from USA (thanks again Daniel)

I still do not know what bent the rotor so to avoid a repeat when I installed the new one I removed all spark plugs and very, very gently rotated the crankshaft by hand while listening for anything that did not sound right.
To remove and replace the rotor I made a rough but effective tool to stop the crankshaft rotating while I removed and replaced the bolt. (see photo in next post)

Hoses were changed and new clamps fitted, the new radiator installed, fluids added, the new rotor installed and all plastics etc were replaced.

My ever patient wife advised me not to try and start the engine until she was present and provided suitable positive female Karma to counter all the muttering and cursing that had emanated from the garage after I discovered the bent pulse generator rotor
This positive influence seemed to work as the bike started first try.

While petrol injected engines do not need bleeding of fuel lines and injectors I followed a tip from this website – I turned the key on and waited until the pump pressurised the fuel lines – this was repeated 5 times with a 15 second wait in between. Do not know if it made any difference but who cares the bike is running and I can get back on the road.

To anyone who looks at the Wing and think they cannot do what I have done I say if you have any mechanical ability give it a try - it is not that difficult but can be fiddly at times.
Take it slow and steady and kept bolts, screws, grommets etc in labelled containers.
Be methodical and you will save yourself lots of money in paying mechanics and will gain a better understanding of your bike
Get a manual – they can be found online at no charge.
I have printed out all 780+ pages only because I had a dying printer and wanted to use up the toner so I now have the complete manual in two large files in the garage – saves me having to refer to the computer
Also I found the parts manual very useful as it shows the breakdown of parts in great detail

I have included some photos - I had planned to provide a more complete gallery for the website as requested.
The problem was by the time I remembered to take a photo I was often already further into the bike.

While checking the VIN number for the bike I discovered from references in the manual that she was actually born in OHIO USA in 2004 so it was ironic that the parts to repair her also came from the parts suppliers in OHIO.

Due to a limit of 8 photos for this post please see next posting for the remainder of the photos referred to above

That is my tale and I hope this is the last major work required for the next 10 years

Ride safe and stay upright
Tony Collins

Last edited by collinsa on Sat Sep 12, 2015 4:14 am, edited 1 time in total.
Posts: 48
Joined: Sat Jun 30, 2012 7:01 pm
Location: Perth, Western Australia, Australia
Motorcycle: 2004 Gl1800
2019 CB500X

Re: Coolant leak

Post by collinsa »

Had to do this separately as download limit was max 8 photos

Bank angle Sensor plug and socket - lime green 3 pins

LH air vent grommet holding nose fairing in place

Water pump - note flex coupling in pump drive shaft
This needs to be inserted vertically when replacing water pump otherwise it will not correctly locate into female slot on drive shaft
Do not forget to install the "o" ring seal onto the body of the pump before installation


Pulse Sensor Generator

Home made tool to hold shaft still while tightening the bolt in the Rotor

Finished product

Once reassembled a FI (Fault Indicator) message on the dash indicated the Intake Air Temperature señor was not operating - quick dismantle of centre console showed I had not properly connected socket onto the sensor
Thanks to this website I was quickly able to determine what 9x std flashes of the FI meant - IAT not connected/ faulty etc

I printed out the list of faults and have added this to my manual for future reference

Ride safe

Now all running sweet
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Motorcycle: 2001 GL1500F6C Valkyrie
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Re: Coolant leak

Post by Aussie81Interstate »

Looks like something has been hitting that radiator?

Great write up as well.

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