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Author Topic: Strange Object in my Gas Tank ('74 CB750K4)  (Read 5817 times)

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Offline Yoshimitsuu

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Strange Object in my Gas Tank ('74 CB750K4)
« on: July 30, 2017, 07:50:44 PM »
Hi all,

Today I finally took the gas tank off the bike and started with my rust removal of the gas tank. I opted to use Metal Rescue as I've heard and seen good things about it (plus their guy on YouTube was very convincing). It's soaking right now so we'll see how that goes.

My question is, when the tank was empty  and before I filled it with BBs and realized the mistake I was making I shook it and it sounded like something was inside. I continued to shake like a teenager trying to pry a pick out of their First Act guitar and pulled out something that looked like leather. I'll post pictures below but inside the tank there probably isn't supposed to be anything right? It kind of looks like a piece of Freddy Kruger's glove.

Also, thoughts on coating the gas tank? I've read the various threads and the crowd seems torn on the topic. I want to spring for Castwell but I've heard that a rust removal will suffice in most cases. I do want to get a lot of life out of this tank though.
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Offline MoMo

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Re: Strange Object in my Gas Tank ('74 CB750K4)
« Reply #1 on: July 30, 2017, 08:19:51 PM »
It looks like old tank liner that failed...Larry
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Offline halllzy

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Re: Strange Object in my Gas Tank ('74 CB750K4)
« Reply #2 on: July 30, 2017, 08:21:43 PM »
Stranger things have been found in gas tanks I'm sure.  If it looks like leather and smells like leather (soaked in gas for 20years), even still tastes a bit like leather it's probably a chunk of leather.
I used Caswell with no issues, just follow the instructions and be sure to get your petcock strainer out before hand.

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Offline halllzy

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Re: Strange Object in my Gas Tank ('74 CB750K4)
« Reply #3 on: July 30, 2017, 08:26:30 PM »
Quote from: halllzy on July 30, 2017, 08:21:43 PM
Stranger things have been found in gas tanks I'm sure.  If it looks like leather and smells like leather (soaked in gas for 20years), even still tastes a bit like leather it's probably a chunk of leather.
I used Caswell with no issues, just follow the instructions and be sure to get your petcock strainer out before hand.

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http://hondachopper.yuku.com//topic/54899

Old tank liner removal thread if you have any concerns.

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Offline Yoshimitsuu

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Re: Strange Object in my Gas Tank ('74 CB750K4)
« Reply #4 on: July 30, 2017, 09:02:11 PM »
Thanks for the replies guys, I always considered that might be an option. Pushes me to continue replacing/checking everything on the bike as the PO's word means nothing since it was apparently "never lined". Oh well :(

The strange thing about it is that it seems to be only that little portion of it. The rest of the tank is not coated with anything. A soap and water + BB swish of water also didn't bring anything else similar to the surface just a little surface rust. Maybe after a 24 hour soak in Metal Rescue more will come out (if there's any more left). Maybe the acetone that I used after the Metal Rescue will unearth more of it...

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Offline jgger

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Re: Strange Object in my Gas Tank ('74 CB750K4)
« Reply #5 on: July 30, 2017, 09:23:56 PM »
Is it metal? If it is maybe someone told a PO that putting a piece of sacrificial metal in the tank would prevent rust????? :P Like putting pennies on the top of an old lead/acid car battery to keep the posts from collecting corrosion. IDK.

Weird, someone somewhere is laughing their arse off right now. Hehe, this will get 'em, they will never figure out WTF this is in here for! He he!
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Offline spotty

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Re: Strange Object in my Gas Tank ('74 CB750K4)
« Reply #6 on: July 30, 2017, 10:50:17 PM »
did the cap have a seal on it ?
maybe its a bit of old leather someone used to seal the cap when they lost the stock o-ringy thing
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Offline Terry in Australia

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Re: Strange Object in my Gas Tank ('74 CB750K4)
« Reply #7 on: July 31, 2017, 03:29:45 AM »
In the old days, condoms were made from leather. Just saying........ ;D
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Offline madmtnmotors

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Re: Strange Object in my Gas Tank ('74 CB750K4)
« Reply #8 on: July 31, 2017, 03:50:58 AM »
Quote from: Terry in Australia on July 31, 2017, 03:29:45 AM
In the old days, condoms were made from leather. Just saying........ ;D

and we recycled them!  :o  ;D


As for liner, I personally would reserve liner for a tank that was leaking. If the inside looks good after de-rusting and it doesn't leak then I would run it. Be sure to oil up the inside of the tank after treating the rust to prevent the return of surface rust.  8)
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Offline ekpent

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Re: Strange Object in my Gas Tank ('74 CB750K4)
« Reply #9 on: July 31, 2017, 04:11:20 AM »
Quote from: MoMo on July 30, 2017, 08:19:51 PM
It looks like old tank liner that failed...Larry
It does look like an old blob of Kreeme.
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Offline Lostboy Steve

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Re: Strange Object in my Gas Tank ('74 CB750K4)
« Reply #10 on: July 31, 2017, 04:48:08 AM »
Quote from: Terry in Australia on July 31, 2017, 03:29:45 AM
In the old days, condoms were made from leather. Just saying........ ;D

That must have been absolutely no fun.


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Offline spotty

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Re: Strange Object in my Gas Tank ('74 CB750K4)
« Reply #11 on: July 31, 2017, 02:40:34 PM »
Quote from: Terry in Australia on July 31, 2017, 03:29:45 AM
In the old days, condoms were made from leather. Just saying........ ;D

that'd be that brand called Rough Rider then
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Offline Terry in Australia

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Re: Strange Object in my Gas Tank ('74 CB750K4)
« Reply #12 on: July 31, 2017, 05:21:50 PM »
Could some PO deviant have been porking your petrol tank........? ;D
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I was feeling sorry for myself because I couldn't afford new bike boots, until I met a man with no legs.

So I said, "Hey mate, you haven't got any bike boots you don't need, do you?"

"Crazy is a very misunderstood term, it's a fine line that some of us can lean over and still keep our balance" (thanks RB550Four)

Offline carnivorous chicken

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Re: Strange Object in my Gas Tank ('74 CB750K4)
« Reply #13 on: July 31, 2017, 07:13:34 PM »
If there's no evidence of liner elsewhere in the tank, I doubt there's a small chunk just floating in there -- another vote for leather (condom)
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Offline Drbjs30

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Re: Strange Object in my Gas Tank ('74 CB750K4)
« Reply #14 on: July 31, 2017, 07:17:28 PM »
I will never line a tank if there are not holes in it. Even then i would be hard pressed to use any liner. The multiple rinses with acetone to remove the failed liner..(ruined my paint..see other thread).  After most of the kreem was out,  the metal rescue that I used worked perfectly getting rid of the rust.  I just kept on shaking it and the filtering the metal rescue through a white tshirt to make sure when i put it back in that there were no remnant kreem particles going back in the tank. This by the way took at ton of time with multiple tank rinses.  I ended up power washing the tank internally to get the rest of the tiny parts of kreeme out that were lurking in the seams.  Make sure you finish with Metal rescue as it will flash rust if you rinse the tank with water.  As per the metal rescue company themselves, there are three things you can do after you use the Metal Rescue to avoid flash rust. 1. rinse with new metal rescue,  2. fill it with fuel, or 3. purchase their Dry coat spray.
 
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Offline jgger

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Re: Strange Object in my Gas Tank ('74 CB750K4)
« Reply #15 on: July 31, 2017, 07:37:06 PM »
Quote from: Terry in Australia on July 31, 2017, 03:29:45 AM
In the old days, condoms were made from leather. Just saying........ ;D

That was for protection................from nasty chastity belts! ;)
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Offline Yoshimitsuu

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Re: Strange Object in my Gas Tank ('74 CB750K4)
« Reply #16 on: August 01, 2017, 07:02:15 AM »
Well, it might as well be a condom because apparently the prior owner stuck something else where his brain needed to go. Oh well, my turn to figure the CB out :)

I ran the Metal Rescue for 24-48 hours and it did a really great job at removing rust. I didn't see any more pieces of liner but there's a drip looking thing inside the tank that's thin but looks like it might be where the liner was poured. It's stable but when I remove the Metal Rescue I'll see if it wants to come out. I removed the petcock and it was worn out from rust but no signs of failed liner gunk but it was rusty. This might also be one of the reasons why two inline fuel filters were installed before it hits th carbs.

I've decided against lining the tank, when I remove the Metal Rescue I'll use the other product they make to protect the tank from flash rusting. During winter, I'll see if I could pick up a new tank and have a family friend paint it. It'll be a good excuse to replace my side covers since they're kind of cracky. Thanks again guys!
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Offline Yoshimitsuu

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Re: Strange Object in my Gas Tank ('74 CB750K4)
« Reply #17 on: August 02, 2017, 10:37:10 AM »
Update: The tank was definitely lined with something and while the Metal Rescue worked wel in the areas that were bare metal it's still heavily cake do in there. I'll have to find a way to remove it without doing harm to the paint since she's my favorite CB color: Freedom Green Metallic. I just wish the inside wasn't Freedom Kreem Liner...
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Offline MoMo

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Re: Strange Object in my Gas Tank ('74 CB750K4)
« Reply #18 on: August 02, 2017, 11:09:35 AM »
Quote from: Yoshimitsuu on August 02, 2017, 10:37:10 AM
Update: The tank was definitely lined with something and while the Metal Rescue worked wel in the areas that were bare metal it's still heavily cake do in there. I'll have to find a way to remove it without doing harm to the paint since she's my favorite CB color: Freedom Green Metallic. I just wish the inside wasn't Freedom Kreem Liner...



You could cover the entire exterior of the tank with painters tape to prevent splash from harming the finish....Larry
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Offline Terry in Australia

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Re: Strange Object in my Gas Tank ('74 CB750K4)
« Reply #19 on: August 02, 2017, 04:07:04 PM »
And don't forget that it was probably lined for a reason, it was a leaker, and if you use Acetone to remove the remaining liner, you will have acetone seeping through the original rust holes, so be careful, and wear a condom! ;D
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I was feeling sorry for myself because I couldn't afford new bike boots, until I met a man with no legs.

So I said, "Hey mate, you haven't got any bike boots you don't need, do you?"

"Crazy is a very misunderstood term, it's a fine line that some of us can lean over and still keep our balance" (thanks RB550Four)

Offline MoMo

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Re: Strange Object in my Gas Tank ('74 CB750K4)
« Reply #20 on: August 02, 2017, 04:49:50 PM »
Body condom?
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Offline ChopSticks

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Re: Strange Object in my Gas Tank ('74 CB750K4)
« Reply #21 on: August 02, 2017, 05:14:38 PM »
https://www.amazon.com/Workshop-Hero-WH290487-Rescue-Remover/dp/B005JVNQPQ/ref=sr_1_1?ie=UTF8&qid=1501719090&sr=8-1&keywords=metal+rescue

Is this the metal rescue that keeps getting mentioned in this thread?

If it is, can it be used over liner? My tank is currently lined but some of you mentioned if it's been lined there's probably a leak, rather than unlining just to reline can metal rescue be thrown in there to clean up the rust spots that weren't caught with the lining? If so, would 1 gallon be enough?
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Offline Drbjs30

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Re: Strange Object in my Gas Tank ('74 CB750K4)
« Reply #22 on: August 02, 2017, 06:21:15 PM »
Quote from: ChopSticks on August 02, 2017, 05:14:38 PM
https://www.amazon.com/Workshop-Hero-WH290487-Rescue-Remover/dp/B005JVNQPQ/ref=sr_1_1?ie=UTF8&qid=1501719090&sr=8-1&keywords=metal+rescue

Is this the metal rescue that keeps getting mentioned in this thread?

If it is, can it be used over liner? My tank is currently lined but some of you mentioned if it's been lined there's probably a leak, rather than unlining just to reline can metal rescue be thrown in there to clean up the rust spots that weren't caught with the lining? If so, would 1 gallon be enough?

Yes, that is the Metal Rescue I have used.  It comes in premixed one gallon size sold at (home Depot), or 14 oz  concentrated to be mixed in one gallon of water (sold by autozone) and if you think about it the concentrate is a better buy for less money.  I have seen 5 gallon buckets available as well if you search the net.

Now for your second question....I am certain that any exposed metal/rust would be cleaned, but..I cannot say whether the new lining would seal properly.  As I have said before, I am not a fan of liners... I would never try to save a failed liner.  Next time, I will use the acetone method but with more care so I wouldn't damage the paint.
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Offline Yoshimitsuu

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Re: Strange Object in my Gas Tank ('74 CB750K4)
« Reply #23 on: August 02, 2017, 07:11:30 PM »
Yes, that's the product. It worked very well on the areas that were rusty such as the top of the gas cap and some areas within that the liner had worn off on. I'm sure once the whole liner is stripped it'll do a nice job as well.

As for it leaking through, that's a concern I have and although there is not really a way I can know before stripping it it might be a gamble I have to make. Hopefully it was just lined by an extremely cautious owner and not someone trying to cover a crack. Outside looks structurally sound, so fingers crossed. Maybe i'll get lucky!
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Offline ChopSticks

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Re: Strange Object in my Gas Tank ('74 CB750K4)
« Reply #24 on: August 02, 2017, 08:04:06 PM »
Thanks, but I was wondering if I could keep the existing lining and just do the metal rescue method then maybe spray some gibbs to stop the flash rusting? or would it destroy the existing lining and need to get relined again?
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