what is the best way to fix crack fuel tank?


57 replies to this topic
  • YamahaWR450FMike

Posted June 17, 2006 - 06:16 PM

#21

JB weld works pretty good.



JB weld is a very stong and durable expoxy that works on almost anything. You local autoparts store will have it.

  • sabin

Posted June 18, 2006 - 09:50 AM

#22

It will not work. JB will not have adhesion with the tank material. There is no known to me method to weld it, you will just loose time and money trying...

  • tshe1

Posted June 18, 2006 - 10:37 AM

#23

OK. here is what i thought to do: first step is to fix the crack that it will not leak again, this is easy task because epoxy for plastics can stop the leak.
the problem is that now the tank have week point and it subjected to forces and stresses that obtain strain.
obviously that will cause the tank to open the crack leak again and...to broke!!
that brings me to to the second step: after applying plastic adhesive to stop the crack from leaking, i will have to stiffen the area surround the crack to prevent stresses applying on the crack, but instead on the stiff area.
i wish to obtain this with fiberglass gluing with poliester (composite material).
and finally, putting rubber foam under the sit places to disperse the forces,stresses that the sit apply, around the tank sides and not directly on the crack area, where it is now.

  • SteadyEddy

Posted June 18, 2006 - 01:49 PM

#24

Good luck buddy, Keep us posted with pics :excuseme:

  • Solo

Posted June 18, 2006 - 07:55 PM

#25

Good luck with that, you are a pioneer and possibly a soon to be hero if you get this worked out and document your steps. Just don't let this little smiley bother you too much :excuseme:

  • Birdy426

Posted June 18, 2006 - 11:07 PM

#26

Epoxy WILL NOT WORK. The problem is that the polypropylene molecules that the tank is made of link with the fuel molecules in the tank, and the plastic gets contaminated. The fuel actually passes thru the plastic on a molecular level. That's why graphics bubble if they don't have holes in 'em; that's why they turn brown; and that's why "natural" or "clear" tanks turn brown after a couple of years if you don't drain the fuel when the bike is sitting. Epoxy is VERY VERY sensitive to surface prep and cleanliness, and since you can't get the fuel out of the plastic (remember, it's on the molecular level), a good fix just ain't gonna happen. A better bet might be either a urethane (again, surface prep is critical...good luck) or an acryllic adhesive. Acryllics are very agressive at the molecular level and are not as sensitive to surface prep. They are also resistant to hydrocarbons (fuels and oils). The problem with acryllic adhesives is that they have very low strain to failure (are very brittle), and are also pretty sensitive to high and low temps. You might try some polysulfide aircraft fuel tank sealant if all you want to do is plug the hole...but it will not add strength and the crack will continue to grow (and create new leaks). A commercial product called "Kreem" is kinda an equivalent. The thickness, contour, and fuel contamination make it not a candidate for plastic welding, either.

Not to piss in the punch bowl, but you aren't going to be able to make a durable fix on that tank. Most cars come with rotatinally molded polypropylene fuel tanks these days. Call your local Ford, Chevrolet, or Daimler Chrysler dealer, and ask the service department if they can fix a cracked plastic fuel tank. They won't help you.

E-BAy is a good place to look. I picked up a used IMS 3.4 gal tank for my son's WR for 50 USD. On average, they go for about a hundred. Even with shipping, that's a lot less than four benjamins!

  • tshe1

Posted June 19, 2006 - 12:54 AM

#27

are you sure that the tank is made of pp plastic?
i found on ebay product that calls: "poly weld".
they declare that it is not glue, but weld in the molecule level of the plastic and it's have the same strength of the material.

http://cgi.ebay.com/...RK:MEWA:IT&rd=1

  • tshe1

Posted June 19, 2006 - 05:30 AM

#28

checked with my dealer today, of how much is new tank and....(you're sitting)
amazing 863 $ !!! (tough here in the middle east)
im ust find better solution for that... :excuseme:

  • Punisher660

Posted June 19, 2006 - 07:19 AM

#29

go factory direct to acerbis, clark, ims, etc. on their web site.....still no more than $145 at the most.

  • Tilson51

Posted June 19, 2006 - 07:23 AM

#30

I saw the crack in my tank as the perfect opportunity to UPGRADE to a larger tank. :excuseme:

thata boy always think BIGGER BETTER MORE HORSE POWER

Visit the ThumperTalk Store for the lowest prices on motorcycle / ATV parts and accessories - Guaranteed
  • tshe1

Posted June 19, 2006 - 10:41 AM

#31

Epoxy WILL NOT WORK. The problem is that the polypropylene molecules that the tank is made of link with the fuel molecules in the tank, and the plastic gets contaminated. The fuel actually passes thru the plastic on a molecular level. That's why graphics bubble if they don't have holes in 'em; that's why they turn brown; and that's why "natural" or "clear" tanks turn brown after a couple of years if you don't drain the fuel when the bike is sitting. Epoxy is VERY VERY sensitive to surface prep and cleanliness, and since you can't get the fuel out of the plastic (remember, it's on the molecular level), a good fix just ain't gonna happen.


what about plastic welding.
i read that polypropylene can be weld good, check this:
http://www.entegrisf...sp?G=1017&ln=en
http://www.twi.co.uk...nd_3/jk56b.html

  • Birdy426

Posted June 19, 2006 - 07:45 PM

#32

what about plastic welding.
i read that polypropylene can be weld good, check this:
http://www.entegrisf...sp?G=1017&ln=en
http://www.twi.co.uk...nd_3/jk56b.html


Again, surface prep is key. As the fuel has bonded with the plastic on a molecular level, it will be liberated and contaminate the joining surface, regardless of the method of "welding" used...heat, heat with filler, or chemical (solvent).

What currency is that 800 bucks for a new tank in? Here in the states, it's about 400 USD for a stock tank. About 225 USD for a brand-spankin' new after market (Clarke or IMS) tank, with better ergos. Yes, there will be shipping, and yes, there will be import duties, but not 500 bucks worth!

  • tshe1

Posted June 21, 2006 - 04:51 AM

#33

talked yesterday with chemical engineer at my work and he was surprised when i told him that the fuel tank is made of polypropylene (does it?),
according to what he knows, fuel tanks should not be made of thermoplast (like here) and the only thing that i can do is to buy a new one because of contamination of the polymer by fuel).
so, if i will buy new one who can assure me that this thing (cracking) will not happens again?

  • Birdy426

Posted June 21, 2006 - 05:43 AM

#34

I'm not sure how smart your CE is...Polypropylene IS a thermoplastic...

No one will assure you that this will NEVER happen again, but there are many, many of us who have replaced our stock tanks (which also cracked at one place or another-Mine was next to the filler neck) with tanks from either Clarke, Acerbis, or IMS, and have many years (3 1/2 in my case), miles (about 3000 in my case) and get offs (too many to count) without any problems.

  • tshe1

Posted June 21, 2006 - 06:09 AM

#35

I'm not sure how smart your CE is...Polypropylene IS a thermoplastic..


i can not undermine my CE knowledge..
but as polypropylene is thermoplastic, fuel tank have shouldn't made from it.
(hope this is understand wording(?))

  • samohT

Posted June 21, 2006 - 06:51 AM

#36

I can tell you how I fixed the crack in my wr400 -00 tank, but is is not a permanent fix. I rode the bike for 3-4 month after with no problems but then I sold it. Yes I told the buyer.

My crack was in the same place as yours and the problem was that when you pushed down on the tank, like pressure from the seat, the ckack opened up. So I put a clamp over the tank pressing it togheter making the crack as wide as possible, then I melted the area with a heat-gun, then I smeared the crack togheter with a soldering iron, then I added glue while the plastic was melted.

The only glue I found to kind of stick to the tank was melt-glue, if added while the plastic was hot, but melt-glue is not resistant to gasoline.


/Thomas

  • EVLXX

Posted June 21, 2006 - 08:09 AM

#37

Here....

http://www.urethanesupply.com/

  • tshe1

Posted June 21, 2006 - 08:49 AM

#38

I can tell you how I fixed the crack in my wr400 -00 tank, but is is not a permanent fix. I rode the bike for 3-4 month after with no problems but then I sold it. Yes I told the buyer.

My crack was in the same place as yours and the problem was that when you pushed down on the tank, like pressure from the seat, the ckack opened up. So I put a clamp over the tank pressing it togheter making the crack as wide as possible, then I melted the area with a heat-gun, then I smeared the crack togheter with a soldering iron, then I added glue while the plastic was melted.

The only glue I found to kind of stick to the tank was melt-glue, if added while the plastic was hot, but melt-glue is not resistant to gasoline.


/Thomas

i filled the tank with water all the way and notice that is leaking from a little spot but not from all the crack.
you're right, when you push on it (like the seat) it is slightly open, but not all the crack, so i think that just little of the crack is going all the way.
i cleaned the area around the crack and then scratch it with sandpaper (grit 80), then i applied on the surface melted plastic (polypropylene) from hot gun. after it cooled, it is extremely hard to pill the "adhesived" plastic from the tank (actually almost can't be done).
now, i filled the tank whit gasoline (1 liter) and lay the tank so the gasoline will be at the cracked zone, and Will see a day or two what will happened to the additional plastic: does it pill easily, does it leak :excuseme: .
do you have a pic of the clamp that you made or more explanation on how you did it?
and another thing, i notice thet the tank side wall thickness is about 5mm!!!

  • Stickshift

Posted June 21, 2006 - 12:08 PM

#39

The plastic tank on my 2001 KLX300 developed a crack, I found a guy near my house that did plastic welding. He repaired the tank, and I have never had any problem with it since.

That being said:
1) Anyone want to buy a KLX300?
2) I would buy an IMS 3.3 gallon tank to replace the stock 2.2 gal.

Regards,

BG

  • tshe1

Posted June 21, 2006 - 12:25 PM

#40

The plastic tank on my 2001 KLX300 developed a crack, I found a guy near my house that did plastic welding. He repaired the tank, and I have never had any problem with it since.

That being said:
1) Anyone want to buy a KLX300?
2) I would buy an IMS 3.3 gallon tank to replace the stock 2.2 gal.

Regards,

BG

1.how much time you run with it fix?
2.do you know what kind of plastic your tank made of?




 
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