Cracked plastic tank! How do I fix it?

[big specht]

My bw350 tank just cracked from old age( it’s stored in a climate controlled garage) and is leaking gas . Is there a way to seal them from the inside ?

[ATC King]

Probably not long term. Plastic tanks are generally much more flexible than metal or composite. A short-term repair would be on the exterior and likely not be to your aesthetic approval.


You could possibly weld it, but being an original tank, it's probably all fragile.


I think new aftermarket tanks are available for the 200, but I'm not certain about the 350.


I'm not so certain climate controlled environments are best for the multitude of materials on vehicles. Humidity control for moisture/corrosion, and out of the weather or direct sunlight, but I think temperature swings are good for many materials as long as they're within limits. I know rubber components need to regularly see operational temps to keep the chemistry active.


Congrats on owning a BW350 though. I hope you can find a solution for the tank.

[oldskool83]

head it up with hand help propane torch it take a good bit for it to turn to liquid. next use something flat and let it all melt back together cool it off with water. I unformed a massive dent into a trx250x gas tank i had to clear a 350x motor. took me about an hour to get it out. The plastic does turn black however but its the under side. I am sure you could put something like a wire mesh on the outside to sink into it so it grafts together. at this point what do you have to loose its already broken.

[big specht]

Well those options would work but I think I found a better one to fit my problem. They still sell new ones for the bw350 ? Who would have thought ? So I ordered one it’s on the way.

[shortline10]

Yes new ones are available but the manufacturer date I bet is probably 15 + years old , their all old stock . Just make sure you use ethanol free gas in the tank or the new tank will crack as well .
I replaced one about a year ago with the same issue as yours .
Was a Mint very low hour Machine .

[schlepp29]

I didn't knew they were ever made. Well specht you dodged the bullet there.

[BOB MARLIN]

They used to sell a product made especially for cracked plastic motorcycle tanks. Kind of like a JB weld for plastic.

[big specht]

? I will see what I can find to fix the old tank

[sweetip2000]

If you can get the same type of plastic as the tank then clean the tank and wipe down area where its cracked. Now sand it with 220 grit sand paper and wipe down with acetone. Melt the scrap plastic that is the same plastic as the tank with a heat gun until its like syrup then get a painters small Spackle blade and scoop up the goop on the blade and smear it on top of the crack. That should seal it. Test for leaks. If it leaks do it again. You can put a tank bra on the tank to cover up the surgery. You can make you own tank bra. Hope that helps.