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2-stroke expansion chamber dent fix question


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Has anyone got there expansion chamber pipe fixed at one of those shops that advertise, they weld ends on it and blow dents out with compressed air?

I'm thinking of sending mine out but I don't want it to come back and be disappointed with the result. It's an fmf gold series pipe, not to banged up, just a bunch of golf ball size dents around the underside on the 1st stage of the chamber.

Any info would be a help, thanks.

Joe

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Since one of those shop owners would retire and move to the Bahamas just on using me as a customer;

I went to the hardware store and bought the Plug/hose/fittings, I can do the same work they do multible times for much less.

  • I found 60-80 psi and Map gas works well
  • Stay off the seams
  • Cover the plug on the cylinder side with a towel so if/when it blows out it will be caught in the towel and not become a missile.
  • Attach the pressure hose with air fitting to the silenser end. Run hose clamp through the rear pipe mount then around the hose to keep it in place.
Edited by AXAxiom
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First time I tried this I had one end blow out and scare the crap out of me. I have been gun shy since. Now when I heat it with compressed air I get scared the heat my ignite any gas/oil mixture still in the pipe. So instead I weld a bolt to the dent, heat it and pull on bolt with a vice grip. Then cut the bolt off and grind smooth. It works but not as pretty as blowing them out.

Do you guys get nervous of making a bomb with that heat and compressed air?

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Do you guys get nervous of making a bomb with that heat and compressed air?

 

 

nah not really.....ive had a few ends blow off its no big deal as long as they arent pointing at anyone

 

 

i dont see how there is any way anything inside the pipe could ignite....

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I have tried both. Cheaper to do yourself but Pacific crest does a really nice job. Both times I had them do it my pipe came back in about a week and looked brand new. They fixed cracks, straightened it to original configuration, and fixed the dents. All without any discoloration. When I did it myself it was ugly afterword.

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A torch and air. About 20 lbs. Cap the engine side and put a hose clamp over it long ways. Than use another to clamp that long clamp to your pipe. One the small end make a plug with a Schrader valve. Put heavy wire across the plug and hose clamp it again. There is a video on YouTube about this.

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Another trick is to fill it with water and put it in a deep freezer.

 

You have about a 50/50 chance of fixing a two-stroke pipe that way, especially if the dent is in the fattest part of the pipe. The pipe has so many complex curves and varying dimensions, that you just cant predict the expansion of the ice. You're just as likely to remove the pipe from the freezer and find it burst open as you are to find the dent gone.

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