Dirt Bike Tech: How to Fix Cracks in Plastic Tanks

Feb. 11, 2015 By Rick Sieman
Hereís the bike with the leaky gas tank. We hoped to find a more inexpensive solution to repairing the tank versus replacing it at $150-$200 a pop.

I got my wife a Yamaha TTR 125 with an electric start. Sheís been on my case to get her something that she can ride. The TTR 125 is low enough for her to put both feet on the floor and the electric start makes getting the motor rolling easy. It was only when I discovered some leaks in the gas tank that my bargain bike seemed a little suspect.

Both sides of the gas tank had cracks and the gas and was slowly dribbling out. I looked around on eBay for tanks and found out they were going for $150-$200, which was not very good news. It was right around then that I saw a YouTube on how to fix plastic gas tanks and watched it to see if it made sense.

Instead of using elaborate plastic repair kits, a small soldering iron is used. The iron has a pointed tip and goes for around 10 bucks at most any RadioShack. The trick is to find the crack(s) and use the soldering iron to melt the plastic and then as a backup system, apply a good plastic glue kit to the repaired area.

So follow along as we do the repair.

After locating the crack in the tank, we took a small soldering iron and very carefully pushed it into the damaged area. At no time during the repair, did we go completely through the plastic.

Here is the soldering iron that we used.  Itís a small unit with a needlepoint and is available from RadioShack for $10.99. Let it heat up real good before you use it.

After the cracks have been repaired with the soldering iron, itís a good idea to apply some sort of the plastic glue over the area. We used some JB Weld Plastic Bonder and it worked real well.

The plastic was applied directly over the repaired area. It set in 15 minutes and was completely cured in an hour.

Hereís the fixed plastic tank ready for use.

Gas was poured into the tank for used to check for potential leaks.

Both sides of the gas tank had small leaks.  After the plastic glue has cured, it can be sanded and given a small coat of paint.

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