GL 1100 Rebuild - Made in France

[FRClément]

Right at this moment I am rather ill, but as soon as I get a chance to get into the workshop I will take some photos.

Thanks a lot! I’ll try to unclog it differents way until you show me yours!

[CYBORG]

looks like it is going well. Waiting to see it finished

[FRClément]

UP

I wish you a happy new year !

I've been very busy lately, but got some improvements

I partially unclog the water bypass, still need to let it soak for a while to disolve any remaining coolant/rust/idkwhatisit

I used some WD40 and soak it for 2-3 weeks then use a brake cable and a brass bottlebrush to scratch the plug. It took me about 2H to see some WD40 dripping out of the front cover.

Next step is to reinstall the front cover and the waterpump.

[gltriker]

snipped-
I was replacing my water pump and i figured out there is a clogged hole that came from the thermostat to the water pump...

Hi,
There is a pressure relief hole that runs from the water pump up to the thermostat housing. I had one engine with the hole so badly blocked that I literally had to drill it clean. The problem with that is that there is angled drilling blanked off with a plug, visible just to the side of the left hand camwheel. I drilled the plug out and tapped a thread into the hole and filled it with piece of threaded brass rod

continued -.
I believe the blockage came from a previous owner using one of the radiator sealants to stop a leak.
If this coolant bypass gets blocked, you have the risk of blowing out the seals in the water pump.

Yes it’s exactly this one! I understood that if this pressure relief hole is clogged, the water in the head does not circulate and it open thermostat too late.
I think this can be a cause that both my head gasket need to be done…

I just don’t understand where to drill, because it’s not a straight line between the in and out?
Thanks!

This isn't an attempt to hijack FRClement's Topic PLEASE NOTE: All the words highlighted in blue are part of their original postings, nothing I have added.

I found this conversation between FRClement and Old Fogey to be VERY interesting!
A situation I had never seen mentioned before, in the 12 years since I joined the Club.
-Please provide photos of both ends of the blocked coolant bypass circuit in your engine.?

In this Topic, FRClement and Old Fogey have presented another probability of why folks are stymied how their engine's cooling system puzzle seems unsolvable. Air bubbles appearing in the radiator filler neck when the engine is running, that can't be traced back to a leaking cylinder head gasket, is the unique example that comes to mind.

Thankfully, My trike's engine has not required any repairs (head gaskets, water pump) since I've owned it.
(Knock on wood, it won't happen now)

( My '75 came to me in 2005 with a metal impellor water pump already installed. 7,831 miles on the odometer. Not sure why, but there may have been cylinder head gasket/s required replacement after the front crankshaft bolt had loosened far enough to bust through the timing belt covers, possibly dismounted a timing belt or two and bent a few valves. I'm guessing all of those probabilities based upon the broken timing belt covers. )
moving on...

Although I replaced the thermostat assy. and the 2 water tubes' 4 orings and 2 elbow gaskets (which carry heated coolant past the opened thermostat, back to the radiator ), at least once since I put it on the road 10 years ago, I hadn't removed the "thermostat case" , itself, off the top of the engine block; therefore, I knew nothing about the existence of a vertical "coolant bypass flow circuit" passage under the front of the "thermostat case" that descends through the left side crankcase to intersect the water pump outflow circuit.

If I hadn't been alerted to its existence by our fellow member, redsrback6, I would never have known about the hidden " coolant bypass flow circuit" passage . Boyce had discovered the passage when he was investigating an unusual, atypical source of an anti-freeze weep . After studying the GL1000 parts breakdowns illustrations, Boyce had determined where the thermostat case bottom side contacts the top surface of the left side crankcase, an oring was located between the 2 parts.

After having seen various photos of heavy accumulations of scale around the exposed cylinders' water jackets when cylinder head gaskets were being replaced, and scale deposits under the lower cast alloy radiator hose fitting/water pump impellor cavity, then putting 2 and 2 together after reading FRClement and Old Fogey's conversations about the plugged coolant bypass passageways, I searched for, then found a cooling system theory of operation illustration in the Honda GL1000 Shop Manual. -- page 118

Screenshot 2023-01-01 230139.jpg (83.85 KiB) Viewed 375 times

[FRClément]

The watercooling system is part of the project, so I think it’s totally ok

I discover this bypass thinking while cleaning the front case and asking me why it was. I then remove the « thermostat case » and find the beggining of this bypass.

Then I thougt : If this sh** is clogged up, the water will heat in the heads, but because there is no flow in the system, the thermostat will take time to open and then -> overheating.

Mine had been sitting for around 15 years, maybe more, so it’s not a great example, but if this bypass get clogged I think (i’m not an expert at all) it can cause cooling problem and in the worst case overheating.

I’ll send the pictures tommorow, here is 2:30am

I hope i didn’t make too much mistakes in english

[CYBORG]

Your english is fine

[gltriker]

The watercooling system is part of the project, so I think it’s totally ok

I discover this bypass thinking while cleaning the front case and asking me why it was. I then remove the « thermostat case » and find the beggining of this bypass.

Then I thougt : If this sh** is clogged up, the water will heat in the heads, but because there is no flow in the system, the thermostat will take time to open and then -> overheating.

Mine had been sitting for around 15 years, maybe more, so it’s not a great example, but if this bypass get clogged I think (i’m not an expert at all) it can cause cooling problem and in the worst case overheating.

I’ll send the pictures tommorow, here is 2:30am

I hope i didn’t make too much mistakes in english

Your English makes perfect sense to me, too

[FRClément]

Here’s the pictures :

79E94D51-DBEC-4723-985D-5ECCE801674C.jpeg (250.74 KiB) Viewed 322 times

38BFC25A-34B6-4AEE-9EE8-214115A7A9A1.jpeg (295.78 KiB) Viewed 322 times

[Old Fogey]

I'm sorry I have not got back to this with pictures. I've been ill for the past three weeks and still am.
The passageway you picture is indeed the bypass. If your thermostat is closed (cold engine) and that passageway is blocked, the water pressure from the pump has nowhere to go other than blow out the pump seals.
Now take the left hand belt , cam wheel, tensioner and rear belt cover off. You will then see the plug I mentioned before.
This picture of a block that someone has already had the problem will show you
https://img.auctiva.com/imgdata/5/9/8/0 ... 848_tp.jpg

[gltriker]

Very Interesting!
Thank you, very much FRClement and Old Fogey ( John ) for making this area photographically clear where the *thermostat case* and top of left side crankcase are connected and sealed together with an o-ring; at the upper end of the coolant bypass flow circuit. The additional photograph of the exposed lower end of the bypass flow circuit is very helpful, too.

John's strategy to expose the horizontal portion of the hidden in manufacture passageway is greatly appreciated, as well. Wow...
AND, John's insight that water pump sealing components will eventually be compromised by an obstructed coolant bypass flow circuit is added wisdom.

Although I may never have need to chase down a coolant bypass flow blockage in my trike's engine, this here-to-fore unknown/never before shown? information will undoubtedly help other folks in the future. Amazing how this stuff is discovered and made known to others. Amazing.

[Fred Camper]

Good picture to include in shop talk perhaps, as it cannot be all that uncommon for an engine sitting a long time to get that circuit plugged.

[gltriker]

Good picture to include in shop talk perhaps, as it cannot be all that uncommon for an engine sitting a long time to get that circuit plugged.

I heartily agree, Jeff ! To locate and add photos of scale accumulation around cylinder bore liners and crud in the water pump impellor cavity will add emphasis to the importance of inspecting the coolant bypass flow circuit, too.

[Old Fogey]

a better view of where the blanking plug is located.
https://www.wingovations.com/blank