Pantheon 05 coolant problems

[Paulf]

In am attempt to steal coolant fuckery thread. I was on the way to work along the a38 doing 55 - 60 mph when I noticed the temp gauge go to the red. So got to work checked coolant expansion bottle when cool and all's good. Going back home same thing happened. So it sit there and use 4 wheels to work.

History brought for almost scrap value. No compression and strange noise on started. To cut a long story short over last winter armed with the workshop manual proceeded to strip it down. Big end really gone and barrel scored to f### so engine out. Other things to do but rebuilt with parts off Amazon and ebay. For cb1 rocket the barrel kit including head gasket was off roller.com Amazon.

Got finally back on road May time after finally getting mot. Not used as much as I would have liked so only done 600 miles since back on road. By the way it a hobby project something I do in my spare time twiddling spanners is fun to me. I have another bike in bits at moment a dylan.

Anyhow to my regret I did not re-torque the head after say 50 miles like I was taught ex-railway diesel fitter. So anyhow with so it looks like my head gaskets gone. Any point in torquing the heads or am I expecting miracles.
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Past bikes simsom mofa 1s, suzuki hustler 250 (£35 in 1973), suzuki ts125k, mz150, yamaha yb 100, honda pc50, honda vision 50, all 2 stroke - then cars - honda pcx 125 (sold) own honda fes 125 and Mrs 125 spares or repairs. Started 1972 all accidents walked away no insurAnce claims

[Tankie]

Really you should replace the gasket, but there is no harm and seeing if pulling the head bolts down will stem the leak. If the coolant bottle level did not move then that needs looking at
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Always learning, everyday is a school day

[cb1rocket]

Get a new oem headgasket and give it a good clean on the head and barrel. No need to retorque these. They are too light at 27Nm

I run a fleet of them and sometimes the aftermarket gasket are shit. Even worse if an old is used but sometimes 50/50 chance.

The overflow bottle should rise as the engine warms up. If not check under the centre panel and remove rad cap and if the coolant has gone down then it's the headgasket. Check also the rubber hose pipes are done up tight too.
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Honda H100S2 Rebuild - https://www.bikechatforums.com/viewtopic.php?t=253852

[Paulf]

Head gasket definitely gone pink coolant now muddy coloured and scummy. What I do not understand coolant reserve full radiator almost empty. Enlightenment please.
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Past bikes simsom mofa 1s, suzuki hustler 250 (£35 in 1973), suzuki ts125k, mz150, yamaha yb 100, honda pc50, honda vision 50, all 2 stroke - then cars - honda pcx 125 (sold) own honda fes 125 and Mrs 125 spares or repairs. Started 1972 all accidents walked away no insurAnce claims

[Tankie]

The coolant expands and contracts with heat, normally as the engine cools coolant will be sucked back into the system but if there is a leak this will not happen
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Always learning, everyday is a school day

[Pete.]

[cb1rocket]

Agree with Pete, except the only thing i have found with these when the head had gone is that the level never rises or blow out of the expansion bottle on these models.

Its doing exactly what the op said and that it stays the same level in the bottle but the water disappears from the rad.

Source: i run a fleet of these (over ten of them) and 3 have suffered this fate
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Honda H100S2 Rebuild - https://www.bikechatforums.com/viewtopic.php?t=253852

[Pete.]

Empirical evidence is always best but I was talking in general terms why it happens to raise the understanding of the process. Many people don't understand the function of an expansion bottle or how it works, and many over-fill them thinking that the level is low too.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[Paulf]

Thanks for all your responses. I was should have said I understand the expansion bottle thing. But most occaisions with cars and and previously at work the expansion tank is higher. So coolant drop.is seen in the expansion tank. So checking the expansion tank is no guarantee system is full my bad. First water cooled bike I have owned and four stroke which I not a fan.....much prefer the smell of 2 stroke.....
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Past bikes simsom mofa 1s, suzuki hustler 250 (£35 in 1973), suzuki ts125k, mz150, yamaha yb 100, honda pc50, honda vision 50, all 2 stroke - then cars - honda pcx 125 (sold) own honda fes 125 and Mrs 125 spares or repairs. Started 1972 all accidents walked away no insurAnce claims

[cb1rocket]

Haha two stroke fan here too. If you were closer i would sort it in a mornings work.
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Honda H100S2 Rebuild - https://www.bikechatforums.com/viewtopic.php?t=253852