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First off, Hi to everyone.. I am new to the world of motorcycle and I just joined this forum to learn about motorcycles!

I bought a used 125cc baimo renegade as a project. just trying to turn it into a bobber style bike.

I have recently found out that the fuel tank has some small holes on the side of it...

so I did search on google and found out that i could use fuel tank sealers to seal it from inside.

however, I have a problem/questioin before I go ahead and get the sealer etc!

what i need to know is what do i need to do with the tank fuel tap hole?

basically, I'm worried about pouring the sealer in the tank and the sealer liquide blocks the small fuel tap hole which is under the tank!


I haven't found any information about this on google and all the videos i found just showing how to pour the stuff in the tank but nothing about keeping the fuel tap hole from blocking when the sealer sets and drys from inside!!!


could someone please advise on this issue?
 

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Hello Rooz, and welcome to the forum.

Typically, I don't use tank sealers to seal pin holes. I use JB quik weld and my own "technique". I use sealers if the tank has rust.

Anyways, I don't worry about the fuel tap hole, cuz you can always unclog the hole with an exacto knife.
 

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A length of appropriately sized wood dowel shoved in the opening if you wish. That is if it is a round opening with a threaded fitting. If it is a flush opening where two screws hold the petcock to the tank, just put screws in place and do as OEJ says with an exacto knife.

OTOH, I'd want a better look at those holes. Or what is around them. How much of the metal is now rust? Poking around the holes with your finger ought to let you know if the rust is extensive enough to be looking for another tank.
 

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OEJ, care to expound upon your technique?
 

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Hey rooz,

I am quite the novice motorcyclist but I'll give you my 2 cents for when I had to deal with my old tank that had a hole in it. I used Seal-All on the hole (exterior) and then used Red Kote to seal the inside.

Also I know Lowe's/home depot has a section called "hard to find parts" that's in the same aisle as screws/nuts/bolts. They sell all different sized rubber stoppers that worked perfectly to plug the fuel line on my tank when i was cleaning it/sealing it.

Like OEJ said above don't worry about it clogging. You can either knock the excess sealant away or just drain the excess sealant out once it has been coated (ie Kreem or Red Kote but might not apply to all sealants I am not sure).
 

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Another method of sealing small pinhole that we used a long time ago is to use lead solder to seal them. Basically it is the same a leading to fill seams and dents. The short of it is to acid was the surface and the flow lead onto the surface. If you can find a body guy in 60's or 70's he can teach you. Leading also works well when doing body work.
 

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Years ago I repaired a lot of small engine gas tanks by soldering. I'm also a big fan of JB weld and will suggest its use to customers looking for a cheap fix they can do themselves. I believe soldering to be the better fix but it takes more skill. It's surprising just how big a hole solder will bridge over with good technique.
 

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think of the gas tank as the brain box of the motorcycle, what would you do if you got holes in there?

So go get a transplant man, and NEVER, and I mean EVER, "...try to repair a gas tank"
 

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Would you expand upon your reasoning? I'm curious because I see no problem in repairing a fuel tank... If you know what you are doing. For example I cracked a welded seam on my 1000 when I laid it down to avoid running off the road after a cager came into lane. Another tank I repaired had a weeping seam and as the bike is an antique I again leaded up the seam as all the parts on the bike are original. I agree that if it does not hurt the value and if one is available then replacement is the way to go. Today so many of the tanks available to vintage bikes are cheap knockoffs or are in worse shape than what you have.

think of the gas tank as the brain box of the motorcycle, what would you do if you got holes in there?

So go get a transplant man, and NEVER, and I mean EVER, "...try to repair a gas tank"
 

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If you're going to weld on a tank it's a good idea to take it to a radiator shop and have them flush it first, but that's no reason not to repair one.
 

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Around here the radiator shops will "boil out" gas tanks and even put sealer in them. I don't know the brand the use and they really don't want to divulge the brand so if I have a tank needing done I let them clean it and I pick up the same day. I keep some of Caswell's gas tank sealer on hand just for emergencies like my tractor tank that rusted due to ethanol.
I recommend that everyone find a gas dealer that sells pure gas. There are web sites that can find the stations for you. If you own an older bike (pre late 60's) get on real good terms with a small aircraft owner and use 110LL if they can get it for you.
 

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Two of my best friends:
http://pure-gas.org/ and http://www.buyrealgas.com/

Fuel tanks can be repaired quite handily if you pay attention to detail. My pre-rust removal procedure includes draining all the fuel out of them and disposing of it by burning. I'll then leave the tank to air dry for a day or two and follow this with a good Dawn dish detergent douching. fill it to the top and leave it standing for a bit, turn it upside down and leave it a few minutes. Drain and rinse. That should have it clear of fumes so it can be safely welded. The last one I've done this with is off an XLCR I bought at auction a year or so ago. Two cracks in the bottom of it that appear to be a common occurrence.
 

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The really old fashioned way to inert a fuel tank so it could be welded was to run a hose from the exhaust to the tank and fill the tank with the exhaust. The CO and CO2 were said to provide a safe environment, of course no one that blew up is around to say it was a bad idea.
 

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The really old fashioned way to inert a fuel tank so it could be welded was to run a hose from the exhaust to the tank and fill the tank with the exhaust. The CO and CO2 were said to provide a safe environment, of course no one that blew up is around to say it was a bad idea.
No oxygen no bang
 

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OEJ, care to expound upon your technique?

For you cmonStart, anything... Sure.
1) If the pin holes are due to rust, then I have to asses whether the tank is repairable or not. Pinholes caused by rust are symptomatic to failure. You fix the pinholes, but then more show up. So you have to be able to tell if the tank is a good candidate for repair or not. Use your best mechanical judgement for that call.

2) I'm gonna go with the rust route here... Sealing rust pinholes is useless if the rust continues to breed in the tank. So before I seal them, I have to effectively kill the rust. I do this with petroleum jelly (naval jelly). put it in the tank and roll it around for max coverage. Follow the directions, then I rinse the tank with water. Blow it out with compressed air to help remove the water. Then I rinse the tank with acetone cuz the acetone helps dry out the water and prep the cleaned metal. After removing the acetone, I apply compressed air again. This is for obvious reasons, To dry out the tank.

3) Now the tank is ready for a proper hole fix. I use JB Quik Weld (sets up in like 6 minutes). I mix the 2 parts together, then wait a minute or two for it to start to set. Then I apply it to the holes, trying to get it into the holes. I do this with the holes pointed upward, so that way the JB seeps down slowly. Then after a minute, I rotate the tank so as to get the JB to try to seep back out the holes. Then I use a plastic putty scraper to smooth it over. All before it hardens. Then let it harden. If there is a dimple or even a hole left, I apply more JB, making sure to smooth it out. That usually seals up the hole quite nicely.

4) Ya still have to address the rust issue. Once something starts to rust, it usually won't stop unless you remove the oxygen from the equation. In the case of a gas tank, you need to coat the inside. I use Kreme Koat. This makes sure that rust will no longer be an issue.


Most of you guys are on the mainland (continental USA), I live in the tropics so rust is a massive problem here. I had to find a solution to it. Replacing the tank with a new one is the best solution, but on older bikes, ya can't always get a new tank. My technique works, it's proven. Best part is if the hole is small and not rust related, it works even better, cuz no need for the kreme koat BS....


Hope this helps you cmonStart!!!
 

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Nice, thanks. Actually similar to mine but I use a toilet bowl cleaner for rust removal, and solder to fill in the holes, then Redkote liner on the inside of the tank.
 
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