Author Topic: Re-treating an already treated tank?  (Read 343 times)

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Offline Vfrman

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Re-treating an already treated tank?
« on: May 23, 2024, 05:48:42 PM »
73 CB350K bought a few weeks ago. No info available from previous owner.

The tank has already been treated. How, when, by what product…no idea. All I know is looking into the empty tank with a flashlight, down at the lowest parts, I can see “bubbles” trapped in a shiny coating that looks like clear polyurethane I have used on wood projects. Is that an indication of a lousy job by whomever applied the tank treatment? When I drained the last little bit of fuel into a jar it was crystal clear…no rust, no crud.

Is it advisable to retreat a tank thats already been sealed?  Not looking to do extra work…but smart work to avoid future problems. I’m taking the carbs off for a full ultrasonic cleaning/rebuild. 
1973 CB350F
many bikes over many years

Offline carnivorous chicken

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Re: Re-treating an already treated tank?
« Reply #1 on: May 23, 2024, 06:24:25 PM »
How about a photo?

I've removed Kreem-lined tanks with acetone, and then recoated using Redkote since you can use acetone to thin Redkote. But Kreme is #$%*e, I mean white, or beige-ish so I'm guessing it's not it.

Offline BenelliSEI

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Re: Re-treating an already treated tank?
« Reply #2 on: May 23, 2024, 06:36:28 PM »
If it’s clean and not leaking, I’d leave it alone.

Offline CycleRanger

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Re: Re-treating an already treated tank?
« Reply #3 on: May 23, 2024, 06:55:12 PM »
If it’s clean and not leaking, I’d leave it alone.

yeah, pretty much. If the current liner isn't lifting or dissolving.
It's a pita to remove a liner, especially if you need to protect the paint.
Do you have a copy of the Honda Shop Manual or Parts List for your bike? Get one here:
https://www.honda4fun.com/materiale/documentazione-tecnica
CB750K5        '79 XL250s     CL350K3
CB750K3        '76 XS650      '76 CJ360T

Offline calj737

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Re: Re-treating an already treated tank?
« Reply #4 on: May 23, 2024, 07:09:58 PM »
The clear epoxy liner is most likely Caswell epoxy. Acetone won’t touch it. The bubbles are from being entrapped during the mixing and not an issue. Leave it be.
'74 550 Build http://forums.sohc4.net/index.php?topic=126401.0
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"Of all tyrannies, a tyranny sincerely exercised for the good of it's victim may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated, but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience." - C.S. Lewis

Offline Vfrman

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Re: Re-treating an already treated tank?
« Reply #5 on: May 24, 2024, 05:13:16 AM »
The clear epoxy liner is most likely Caswell epoxy. Acetone won’t touch it. The bubbles are from being entrapped during the mixing and not an issue. Leave it be.

Good deal, thanks to all. I will leave er alone.

(Calj737- I love that CS Lewis quote in your sig file)
1973 CB350F
many bikes over many years

Offline calj737

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Re: Re-treating an already treated tank?
« Reply #6 on: May 24, 2024, 06:14:47 AM »
Calj737- I love that CS Lewis quote in your sig file
  ;)
'74 550 Build http://forums.sohc4.net/index.php?topic=126401.0
'73 500 Build http://forums.sohc4.net/index.php?topic=132935.0

"Of all tyrannies, a tyranny sincerely exercised for the good of it's victim may be the most oppressive. It may be better to live under robber barons than under omnipotent moral busybodies. The robber baron's cruelty may sometimes sleep, his cupidity may at some point be satiated, but those who torment us for our own good will torment us without end for they do so with the approval of their own conscience." - C.S. Lewis

Offline Stev-o

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Re: Re-treating an already treated tank?
« Reply #7 on: May 24, 2024, 07:14:19 AM »
+1...sounds like a Caswell epoxy coating which can be good if done properly
'74 "Big Bang" Honda 750K [836].....'76 Honda 550F.....K3 Park Racer!......and a Bomber!............plus plus plus.........