Cleaning Inside Exhaust Pipe

[islandscrub]

Anyone know how this is done?

[benji]

Typically with a barbacue or torch. Heat it up for a long enough time and it should start burning out the excess fuel and carbon.

[gsx600racer]

If you like playing with fire, you can try this route.

[ThaiGyro]

My personal preference is to give it a solvent flush, if you have the time and patience. It costs more.

It involves rigging up your pipe with something to seal the port and exhaust ends. I have used a 1" expansion plug on the 50cc at the head end, with a hole drilled for tubing connection.

On the exhaust end you can rig up a rubber plug or a cork but still need a hole for tubing. I then use a 2.5 gallon, or bigger fuel can with an inlet port from the head end (as the return...I go backward flow) and a bottom port to the pump, then pump to the exhaust end.

Back flow will give ok velocity in the chamber sections and allow more poop to easily escape the head end. I pre-fill the pipe with cheap solvent, like diesel...or a diesel/petrol blend.

I use a cheap centrifugal pump...12 volt or plug in. Set it up so you don't clean your floor and let it circulate for a long time. A pain to setup, but gets better results.

If you think that too painful...simply fill chamber about 50%...plugging both ends and shake it back and forth until your arms fall off. Then ask your little brother to do it and so on.

Once you think it is enough, do it again until you want to cry, then drain some from the easiest end...slowly, through a nice filter into a clean container, so you can see what comes out. (You may need to re-use the fluid)

Adding bearings or other hard spheres can help the shake method...(They must come back out the big end, so count how many you put in)

[pinkscoot]

I have done the heat method with a heat gun. It takes some time to get it hot enough to fire, when it does just keep the heat on until it runs clean. Careful because the pipe gets really hot. Welding gloves and eye protection are a must.

[jbjhillbilly]

If you use a BBQ, use one you aren’t going to cook food with anymore. The fumes from the pipe are not tasty.

[islandscrub]

My personal preference is to give it a solvent flush, if you have the time and patience. It costs more.

It involves rigging up your pipe with something to seal the port and exhaust ends. I have used a 1" expansion plug on the 50cc at the head end, with a hole drilled for tubing connection.

On the exhaust end you can rig up a rubber plug or a cork but still need a hole for tubing. I then use a 2.5 gallon, or bigger fuel can with an inlet port from the head end (as the return...I go backward flow) and a bottom port to the pump, then pump to the exhaust end.

Back flow will give ok velocity in the chamber sections and allow more poop to easily escape the head end. I pre-fill the pipe with cheap solvent, like diesel...or a diesel/petrol blend.

I use a cheap centrifugal pump...12 volt or plug in. Set it up so you don't clean your floor and let it circulate for a long time. A pain to setup, but gets better results.

If you think that too painful...simply fill chamber about 50%...plugging both ends and shake it back and forth until your arms fall off. Then ask your little brother to do it and so on.

Once you think it is enough, do it again until you want to cry, then drain some from the easiest end...slowly, through a nice filter into a clean container, so you can see what comes out. (You may need to re-use the fluid)

Adding bearings or other hard spheres can help the shake method...(They must come back out the big end, so count how many you put in)

So this setup is just a circulation system? Do you need to change out the fluid/clean the pump a couple of times or is one batch enough?

I am kind of leaning towards a lye/caustic soda method, though the heatgun option is available to me. The gun seems a little less.. destructive than the roofing torch method.

[oldgeek]

I have never cleaned an exhaust pipe myself, but I imagine quite a bit of heat is needed to cook the oil and carbon out. I have never heard of using lye to clean a pipe, but use caution if you go that direction. 1/4 drop of lye in the eye and its game over, also I would rather get kicked in the jewels than stick 1/2" of a finger in hot Sodium Hydroxide again.

[jackrides]

Try calling some radiator rebuild or chrome plating shops to have it run thru their cleaning process. Afterwards, it will need to immediately be prepped and pinted.

[scooterpimp]

I use to do the old vespa pipes in a similar fashion as in the video , minus the beer & satanic voices toward the end.

[jeff84]

get about 8 pallets stack them up with the pipe about 1/3 from the bottom of the stach and them catch it on fire. after what should be a fire that burns several hours flush the pipe with water. prepare and paint the exterior with vht paint. pur some oil in side and coat all inside surfaces. then bake off the oil residue in an oven that you don't use for food or reinstall and the burning oil smell will go away within 10hrs or so of engine run time.

[islandscrub]

Jan 13, 2018 11:02:58 GMT -5 pinkscoot said:

I have done the heat method with a heat gun. It takes some time to get it hot enough to fire, when it does just keep the heat on until it runs clean. Careful because the pipe gets really hot. Welding gloves and eye protection are a must.

Which end do you put the heat gun on?

[ThaiGyro]

Jan 13, 2018 14:29:14 GMT -5 islandscrub said:

So this setup is just a circulation system? Do you need to change out the fluid/clean the pump a couple of times or is one batch enough?

I am kind of leaning towards a lye/caustic soda method, though the heatgun option is available to me. The gun seems a little less.. destructive than the roofing torch method.

I should have given a "condition" statement: The actual method or combination really depends on your pipe mess inside. Caustic soda method should be done after an acid wash, followed by a fresh water rinse. (and protective oil blast inside until you run it.)

My Gyro OEM exhaust had both goo and carbon crystals inside it's goofy baffles. I used solvent on repeated "once-tru" batches, until solids were gone.  Meaning, I pumped a few gallons through and into a bucket with a cheese cloth strainer to catch/view the debris. I did this quite a few times, but still had a solvent mix getting darker....picking up more goo, after solids were gone. If I had heated the mix or the pipe to around 120 deg. F, it would have taken less time. (120 is fairly safe, as the petrol/gasoline has a 120 flash. The diesel is about 150) The mix loses temperature, so will remain below that. If you use just diesel, you can go to 140...that is my hands limit to touch anything...above 140 hurts, 140 you can hold for a few seconds.

If you're good at cleaning often...high use, high frequency, then it should be a simple task.  Bad like mine when I bought it...then solvent, followed by acid, then caustic is the best. Ask anyone who makes beer. A CIP system (Clean-in-Place) used that method for Stainless. 
*Solvent wash OK to heat, but not hot!
*Acid is done cold, after pipe is room temp.
*Caustic is done cold
*Rinse water should be distilled or RO water...never city, not well water if too hard. Mote that softened water contains higher levels of sodium. If you can't test it, don't use it!

BTW, I am not a heat gun method fan. You cannot control hot spots, because you can't measure them. You could be weakening the metal. Wall thicknesses vary...16 ga., 18 or 20 ga. If you have a marginal weld, the gun might just find it.

A welder would know this. I weld as a hobby and have seen crazy shite happen with simple welds on unknown material condition.

[Lucass2T]

I have a pit which i fill up with coal and bury the pipe in. So it heats up at the same rate from front to back. Turn it over once in a while until no more fumes are coming out. Let the pipe cool off for a few minutes (thin steel looses its temp very fast) and then you can remove all the then powdery residu inside with some tapping.

Make sure soon as possible to rub the pipe with some wd40 or thin layer of light oil afterwards to prevent rusting.

[pinkscoot]

Jan 14, 2018 3:18:11 GMT -5 islandscrub said:

Jan 13, 2018 11:02:58 GMT -5 pinkscoot said:

I have done the heat method with a heat gun. It takes some time to get it hot enough to fire, when it does just keep the heat on until it runs clean. Careful because the pipe gets really hot. Welding gloves and eye protection are a must.

Which end do you put the heat gun on?

I put it on the engine side since the hole os larger.