Blowing out Exhausts

knobby

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Hopefully I haved picked the right catergory to list this.. sorry if I haven't Mods :D
But Im looking for advice on blowing out 2 stroke exhausts they have large dents in them, I believe you can get kits to seal off each end and then attach an airline/foot pump, increase pressure and then apply heat in order to tease out the dented area..

Questions :confused:

Has anybody made one up themselves, if so how easy and can you enlighten me

Or does anybody have something lying in the back of the shed/garage they can take picc's off so I can copy

Or I'm I waisting my time and just buy a new front pipe
 
Go onto the VDSR site Knobby , lots on there have 2 strokes and ime sure ive read a thread on this topic before on that site:thumb
 
Dont ever use an airline. If the silencer ruptures it will go off like a bomb and do some serious damage.

What you've seen is hydroforming. Fill the chamber completely with water which is incompressible. If you continue to pump more in then you will force out any dents in the chamber. You can generate immense pressures inside it in complete safety because if it ruptures or leaks you've only got the tiniest bit of compression before the water returns to atmospheric pressure.
 
you can get kits that clamp over each end of your pipe you dont tremendous pressure or you can deform the pipe before you start then heat the dented area and it will come back to a respectable shape, look on e bay well worth the trouble dents eat your power
 
Wow, wow, wow, wow...... sweet child o' mine!:D
First of all, what bike's it off Knobby...... and secondly, how did you damage it?:p
 
Nearly right.

With a 2 stroke exhaust, it tends to fill up with carbon over a period of time.This inhibits perforamce to a great extent, expecially on motocross bikes.

If you wish to take the dents out, you must first remove the carbon.
If you have access to either oxy-acetelene or a large gas torch, heat one end of the exhaust to red hot. Now blow air into the exhaust using, for example, a vacuum cleaner with a "Blow" facility. The carbon inside the exhaust will start to burn fiercely, and heat may be removed from the outside of the pipe. The red hot section will slowly move down the full length of the pipe.
The smoke from this process is immense. Afterwards, the exhaust will feel incredibly light, and afer cooling, plugs may be fitted in each end & pipe pressurised with compressed air, with localised heat applied to the dent. It will pop out.

I have often used the same process on motorycle petrol tanks. Don't try to remove all of the petrol. It is not possible. Remove the oxygen. This is possible. Find a petrol car. (Not a diesel) Hang the tank over the exhaust for around 20 mins, with the exhaust pipe into the filler. After 20 mins, remove from exhaust & snap filler shut. With all of the other vents plugged, put 2 or 3 small rachet straps round the tank to stop it expanding where you don't want it to.
Get a bottle of argoshield & using a regulator, pressurise the tank as required. Take oxy-acetylene and heat the area with the dent. It will pop out.
I have done the aboove many times, both to take out dents and to weld.
For some reason, everyone I know clears the shed & yard whilst I am doing this. I can't think why.
Myke
 
Cheers guys thanks for the replies, my local motorcycle one man band sussed it out he uses a kit plug each end with an air valve and gently heat it up , job's a goodun


T.

I bought the bike with a slight dent in it, it wasn't me that made the dent , so all good for MM..... 250 exc 2 stroke 2011
 
Myke Rocks said:
With a 2 stroke exhaust, it tends to fill up with carbon over a period of time.This inhibits perforamce to a great extent, expecially on motocross bikes.

If you wish to take the dents out, you must first remove the carbon.
If you have access to either oxy-acetelene or a large gas torch, heat one end of the exhaust to red hot. Now blow air into the exhaust using, for example, a vacuum cleaner with a "Blow" facility. The carbon inside the exhaust will start to burn fiercely, and heat may be removed from the outside of the pipe. The red hot section will slowly move down the full length of the pipe.
The smoke from this process is immense. Afterwards, the exhaust will feel incredibly light, and afer cooling, plugs may be fitted in each end & pipe pressurised with compressed air, with localised heat applied to the dent. It will pop out.

I have often used the same process on motorycle petrol tanks. Don't try to remove all of the petrol. It is not possible. Remove the oxygen. This is possible. Find a petrol car. (Not a diesel) Hang the tank over the exhaust for around 20 mins, with the exhaust pipe into the filler. After 20 mins, remove from exhaust & snap filler shut. With all of the other vents plugged, put 2 or 3 small rachet straps round the tank to stop it expanding where you don't want it to.
Get a bottle of argoshield & using a regulator, pressurise the tank as required. Take oxy-acetylene and heat the area with the dent. It will pop out.
I have done the aboove many times, both to take out dents and to weld.
For some reason, everyone I know clears the shed & yard whilst I am doing this. I can't think why.
Myke
Click to expand...

Fair play!:thumb2
 
I was once told that if you have a dented tubular down pipe a simple solution it to fill the dented area of the pipe with water and freeze overnight.

Never tried it but I'm prepared to believe it :nenau
 
Tunneruk said:
I was once told that if you have a dented tubular down pipe a simple solution it to fill the dented area of the pipe with water and freeze overnight.

Never tried it but I'm prepared to believe it :nenau
Click to expand...

It really does work. :thumb2

<iframe width="420" height="315" src="http://www.youtube.com/embed/Fcmnde21R-0" frameborder="0" allowfullscreen></iframe>
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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