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Air to pop dent in Expansion chamber

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So Ive read up on how to do this an understand what it takes to plug the small end but what are you guys using on the big end when applying air? I have the compressor and blow torch, the small end rubber plug but Im not sure what to use for the larger end.

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My friend used some rubber automotive shock bushings. He put them on a long bolt and when he tightened them together they expanded and plugged off the hole.

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Fill it up with water , Plug the holes and toss it in the freezer for a couple hrs.

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My friend used some rubber automotive shock bushings. He put them on a long bolt and when he tightened them together they expanded and plugged off the hole.

Sounds like a good idea. This thread is a good idea, I never thought about blowing out a pipe using a torch to make the metal more malleable.

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Fill it up with water , Plug the holes and toss it in the freezer for a couple hrs.

never ever do that with a 2 stroke expansion chamber dude. when water freezes it expands i ALL directions it will tear apart your welds TRUST ME, I HAVE FIRST HAND EXP.. only good for 4 strokes

and for blowing out your dents.. Be carefull, i had a guy do it for me and it deformed the shape of my expansion chamber so it does not seat correctly in the engine and the holder:foul:

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never ever do that with a 2 stroke expansion chamber dude. when water freezes it expands i ALL directions it will tear apart your welds TRUST ME, I HAVE FIRST HAND EXP.. only good for 4 strokes

and for blowing out your dents.. Be carefull, i had a guy do it for me and it deformed the shape of my expansion chamber so it does not seat correctly in the engine and the holder:foul:

I see, what exactly did he do that caused this?

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Holy hell they use a lot of pressure, i only used 30lbs and that was on a Gnarly pipe, however/whenever you do it try not to stand in frt of the plugs incase they happen to blow out from the pressure. If it happens to make your alignment off just try mounting it and pay attention to how it needs to go, i put mine on the floor and stuck a 3' pipe in the header end and tweaked it little bits at a time until it line up nice

Here's where i got the info except they use a vise to hold it

http://piperepair.com/tips.htm

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I had to go up to 60 psi, one of my buddy with his kdx pipe had to go much higher,

IMG_6723.jpg

IMG_6721.jpg

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Take a coke or water bottle cap drill a hole in it just big enough so that a big truck tire valve stem sticks through it snugly. The truck tire rubber valve stem will fit snug in the small end of the pipe. And the bottle cap will go over the outside of the pipe on the small end. Then put a hose clamp on it so it doesnt blow out.

Then get a big rubber 1.75" freeze plug from a auto parts store. Put it in the big end and tighten the nut to make it squeeze out and get tight in the pipe. Then put some air in the pipe with the valve stem and heat the pipe wereever you need to. This procedure has always worked on my 125 pipes. Never tried it on a 250 pipe but should still work.

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I used this method to pop a dent out of my 06 stocker pipe. I went to a radiator shop and had them use their radiator plugs that they use for testing. Then filled the pipe up with some air (not even sure how much) and put a blow torch to it. Soon enough my dent was gone and the pipe was ready for a fresh coat of paint :banana:

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what kinda paint to you use for the Expansion chamber. i got a used 250 and it has an aftermarket pipe and it is a little rusty. i have been use a scotch pad and getting it back to metal color. i do have a few little dents i need to have removed also. also it looks like the lower mount needs to be replaced. the metal plate that bolts to the bike is coming apart from the rubber

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I've repaired my own pipes for years. I use a radiator inlet plug for the big end and made the small end one using high pressure hose purchased at an auto parts store, a pvc connection with an adaptor for the male air hose connection. The hose is about 3" long and slips over the small end and is secured with a hose clamp. The inlet plug is inserted after I clean out any oil and tightened then secured with safety wire(it will blow out!). Most often it will take about 50 to 65 lbs of pressure. When heating the dent, start from the outside and work slowly to the middle, making the middle a cherry red. It's ideal if you have a body hammer to work the outer edges of the dent, don't hit it hard just work around it and it should be pretty smooth. Let the pipe cool naturally so as not to make the metal brittle.

I will tell you this, after blowing out the plug a couple of times you will be as nervous as a sheep at a coyote convention.

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I had to go up to 60 psi, one of my buddy with his kdx pipe had to go much higher,

IMG_6723.jpg

IMG_6721.jpg

Thats a pretty cool set up.:banana:

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That's pretty sketchy using expanding plugs like that. I'm sure they hold, but what if they don't... you have a rubber and steel bullet.

I'll try to get some pictures, but you can do it with some cheap automotive muffler clamps.

Weld a bolt to each side of the muffler clamp, then make a flat steel end cap with holes in each side for the bolts you welded to the muffler clamp. glue some rubber to this end cap to seal it.

Clamp the muffler clamps to each end of the pipe with the bolts sticking out past the end of the pipe.

Bolt the end cap on, you can tighten it until the rubber squishes out a little for a good tight seal.

One end cap needs a fitting for your air line. Regulate the air pressure. I stay under 60 PSI.

Heat the dent working in to the center. When it turns a nice orange color, it will just push right out. If there is sort of a raised ring around where the dent was, just use a hammer and lightly tap that ring down while using some heat. it will smooth out easily.

It's a simple rig that can attach to any size pipe safely, it can't come off.

I'll try to get some pictures up tonight.

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That's pretty sketchy using expanding plugs like that. I'm sure they hold, but what if they don't... you have a rubber and steel bullet.

You should always be careful working with compressed air, doesn't matter what setup you have.

...and believe me, those plugs are going nowhere. :banana:

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That's pretty sketchy using expanding plugs like that. I'm sure they hold, but what if they don't... you have a rubber and steel bullet.

I'll try to get some pictures, but you can do it with some cheap automotive muffler clamps.

Weld a bolt to each side of the muffler clamp, then make a flat steel end cap with holes in each side for the bolts you welded to the muffler clamp. glue some rubber to this end cap to seal it.

Clamp the muffler clamps to each end of the pipe with the bolts sticking out past the end of the pipe.

Bolt the end cap on, you can tighten it until the rubber squishes out a little for a good tight seal.

One end cap needs a fitting for your air line. Regulate the air pressure. I stay under 60 PSI.

Heat the dent working in to the center. When it turns a nice orange color, it will just push right out. If there is sort of a raised ring around where the dent was, just use a hammer and lightly tap that ring down while using some heat. it will smooth out easily.

It's a simple rig that can attach to any size pipe safely, it can't come off.

I'll try to get some pictures up tonight.

SOunds interesting and I would definitely like to see some pictures of it

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That's pretty sketchy using expanding plugs like that. I'm sure they hold, but what if they don't... you have a rubber and steel bullet.

Speaking from experience, 40-50 psi is a LOT of pressure. You can get by with freeze plugs if you safety wire them in place, so that if the plug blows off nothing gets damaged. But I think the muffler clamp rig is a better idea, and has the advantage of working on bikes with different pipe diameters.

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