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How to Fix a Cracked 2-Stroke Pipe (Easiest Method)


cracked two-stroke pipe: how to fix it.

Wondering about the easiest way to fix cracks in a 2-stroke exhaust pipe? Maybe your motorcycle was banged up in a crash or from riding rough terrain. You’re thinking you may have to replace the 2-stroke pipe, but you’re hoping there might be an easier, cheaper fix. You’ve come to the right place!

The easiest way to fix a cracked 2-stroke pipe is to apply epoxy or exhaust tape to the crack. Make sure the product is rated for small engine pipes or automobiles. Clean the area around the crack with a wire brush, sandpaper, and acetone, then follow the instructions on the epoxy or exhaust tape.

Read on for a more detailed explanation of how to fix a cracked 2-stroke pipe with epoxy or exhaust tape, as well as other methods for fixing the pipe.

Can You Fix a Cracked 2-Stroke Pipe Yourself?

It is possible to fix a 2-stroke pipe on your own, and some fixing methods are easier than others. Of course, it’s common to sustain dents in the pipe, and there are several options for removing the dents. But there aren’t as many good solutions for cracks. 

The best method for fixing a cracked 2-stroke pipe is to weld over the crack, which we’ll discuss in more detail later on in this article. The problems with welding are that not everyone has a welding gun laying around their garage, and it is easy to make the crack worse if you don’t know what you’re doing.

The easiest way to fix a cracked 2-stroke is to use epoxy and/or exhaust tape. Depending on how much you use your bike and the quality of the epoxy and exhaust tape, this may or may not be a permanent option. But it is much cheaper than buying a new pipe and much easier than welding the crack, so it may be worth a shot.

In the next section, we’ll take a closer look at these two methods of fixing a cracked 2-stroke pipe.

Easiest Way to Fix a Cracked 2-Stroke Pipe

When repairing your 2-stroke exhaust pipe the easy way, you can use either epoxy or exhaust tape, or a combination of the two. You’ll need a few other tools to get started.

Things You’ll Need

  • Extreme heat epoxy
  • Wooden dowel
  • Exhaust tape
  • Wire brush
  • Sandpaper
  • Acetone or nail polish remover
  • Rags or shop towels

Note: If you aren’t familiar with the shape and design of a 2-stroke exhaust pipe, this helpful video will shed a lot of light on it:

How 2-stroke exhaust pipes work | Offroad Engineered

Clean the Pipe

The pipe will likely have a buildup of exhaust, grease, and dirt around the crack. Even if it looks fairly clean, you’ll want to give it a thorough cleaning to make sure the epoxy and exhaust tape adhere to the metal.

Start by scrubbing the pipe with a wire brush. Scrub all around and over the crack, as well as around the diameter of the pipe. Use the brush to remove the worst of whatever might be built up on the metal.

Once you’re done with the wire brush, use sandpaper for a finer polish. The sandpaper will remove smaller bits of grime and will lightly scrape the surface of the pipe so the epoxy or tape will bond more firmly. 

Finally, after smoothing away the last of the visible grime with the sandpaper, apply acetone for a final thorough clean. The acetone will remove any invisible speck of dirt or dust and ensure a stronger seal.

If you don’t have acetone on hand, you can use nail polish remover instead, as acetone is the main active ingredient in it.

By now, you should have a dry, completely clean, and lightly scored pipe. You’re ready to patch the crack.

Apply the Epoxy

Epoxy will typically come in a tub with two chemicals separated out from each other. You’ll need to mix it up with a dowel before using it. As soon as it’s mixed up, apply it to the crack, following the directions included with the epoxy.

The mixture will begin to set pretty quickly, so you’ll need to work fast. Be sure and cover the entire crack and the surrounding area, generously applying the epoxy so there are no weaknesses or thin spots.

A simpler alternative that I like is a high heat epoxy putty stick made by J-B Weld (link to Amazon). Either this or the two-part epoxy liquid is suitable so long as you make sure that you use one made to withstand high levels of heat.

At this point, if you want, you can apply exhaust tape over the epoxy for an extra layer of strength. Otherwise, allow the epoxy to cure and harden. Different types of epoxy will harden at different rates, so be sure to read the instructions to know how long you should allow it to sit.

Tape the Exhaust

If you’re planning to wrap exhaust tape over the epoxy, or use exhaust tape on its own, now is the time to apply it. Wrap the tape around the pipe, adding layer after layer until the epoxy or the area surrounding the crack is completely covered. 

You’ll want the tape to extend at least a couple of inches beyond the crack on each side to make sure it seals properly

Again, follow the instructions included with the tape as you apply it. Not all exhaust tape is made the same, so there may be different instructions for how to apply it or different warnings to keep in mind. 

Make sure the tape you use doesn’t require the pipe to be warm. Unlike repairing a car exhaust pipe, repairing the 2-stroke pipe on a motorcycle requires you to remove the pipe first, so you’ll need to use a tape that can adhere to a cold or room temperature pipe.

Other Options for Fixing a Cracked 2-Stroke Pipe

As mentioned earlier, using epoxy and exhaust tape is the easiest way to repair a cracked 2-stroke exhaust pipe, but it may not be the best way. Over time, the tape or epoxy may weather and break down. So, you may be wondering, are there any other ways to fix a cracked 2-stroke?

Weld the Pipe Closed

Often, depending on the size and location of the crack, it can be welded. If you have a basic welding gun that can use steel thread, simply use the welding gun to fill in the open space of the crack. 

Once the welding metal has set, it’s a good idea to test the pipe and make sure you have a complete seal. You can do this by closing off one end of the pipe, spreading soap over the welded crack, and blowing air into the other end. If the seal is bad, you’ll notice bubbles forming anywhere air the leaks from the crack. 

If this happens, clean and dry the surface, then weld back over it, adding extra layers of reinforcement wherever necessary.

Be careful as you weld. The pipe metal is thin and easy to puncture. This YouTube video gives a good overview of what you will be up against:

How to fix weld a crack in a 2 stroke pipe with Cheap Harbor Freight Welder

If you don’t have the equipment or don’t want to weld it yourself, you may be able to have it done at an auto or small motors shop. If the weld is done properly, it should last longer than epoxy or exhaust tape.

Replace It Entirely

Some cracks may be so large that you simply can’t fix them. The replacement cost may be $250 or more, so this isn’t the cheapest fix. That said, it is probably the best option, since no patch job can be guaranteed to be effective or long-lasting.

Final Thoughts

And there you have it. Replacing a cracked 2-stroke pipe is possible, and it can be done fairly easily using epoxy or exhaust tape. For a longer-lasting fix, you can weld the crack instead. If the crack is especially large, though, your best bet is simply to replace the pipe.

Teddy Henderson

Teddy is always fiddling with small engines, picking up thrown-out string trimmers or tearing apart dirt bikes. He shares what he learns along the way. Hopefully, you'll have less headaches than he has had by learning from his mistakes.

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