De-carbon 2 Stroke exhausts

[Racey Rider]

While taking the motor our of my KR150, I noticed the exhaust pipe is full of carbon depoist from the two stoke motor. This is not only more weight I don't need, but won't allow the motor to breath properly.
Any ideas on how to clean this out?

[Jackrat]

While taking the motor our of my KR150, I noticed the exhaust pipe is full of carbon depoist from the two stoke motor. This is not only more weight I don't need, but won't allow the motor to breath properly.
Any ideas on how to clean this out?

I always used to clean my baffles with a gas torch.
Ya' got'a get em' red hot and it is messy an takes time but is worth it in the long run.I never tryed to clean out a complete system,just the baffles always seemed to do the job.I have no idea how your pipe works but the two stokes
I had could be taken apart,like header,muffler and baffles.
Maybe one of the shops will have an evil an nasty acid type cleaner.
Good luck.

[Kickaha]

Gas torch up the pipe then add compressed air up the pipe then it will burn by itself.

[curious george]

Carbolic acid is supposed to be the stuff. I used BASOL 88. Make a warm solution and leave for a overnight. Not to sure what to do with the stuff afterwards though. :wacko:
Perhaps the local shop might do the whole job for not a lot?

[Racey Rider]

Re gas torch.
Saw a guy do this once. Light it up at one end getting it hot and burning. Then feed striaght oxygen into the pipe, which keeped it glowing as a hot ring of burning carbon slowly moving through the pipe. Pitch black carbon smoke pouring out the end.
Was hoping for a more environment freindly way of doing it. As I asked my wife, and she dosn't have a gas touch ether! :no:
Will inquier about the acid approch.
(As the world could do with a bit more ACID spread around the place !) :rolleyes:

[Motu]

With a removeable baffle I do as the others say,take the baffle out,get it stinking hot and feed extra oxy,this burns the oil out of the carbon.Destroys the finish on the pipes,like if they are chrome they will now be blue.Then you smack it round a bit to loosen the carbon and shake it out.On a one piece system like a scooter I just cut them in half,burn out each end and weld it back together - you can't just burn out these ones as the loose carbon will block the small pipes they have.I have always wanted to try out the caustic soda method,but in a workshop it takes too much time and is messy - it was always easier to send me out the back and smoke the neighbourhood out.Make a strong solution of caustic soda in some container that you can lay the whole system in,let it soak for a few hours,then hose out with water.

edit here - caustic soda is an alkali not an acid,but it certainly is not neutral and will burn your skin and eyes just like acid - take care....ok?

[beanz]

Just found these links:

http://www.vjmw.org/workshop/before_rechroming.htm
http://www.vjmw.org/workshop/exhaust.htm

I'm going to attempt the hot-mix-of-scary-stuff method. Wish me luck

[spudchucka]

I saw it done once about 25 years ago when 2 stroke road bikes were more common. They used some type of solution in the pipes, then applied heat and once it was burning they somehow attached a vacum cleaner to blow air into the pipes. You could see a glowing red hot line moving slowly along the pipe as the carbon and gunk burnt away. It created heaps of smoke, which was no doubt highly carsenogenic (spelling? cancer causing).

[speedpro]

Caustic soda is what you use, the same as drain unblocker. Jam a potato in the end of the pipe and then pour in the powder. Give it a good dose then add hot water a bit at a time till it's full. Give it a good shake as you go. This method saves having to mix up corrosive stuff and then try to pour it in without spilling it on anything you like, such as your own hand. You will need to do it a few times to get it clean. Leave it a while between times to work. Remember it is corrosive so don't leave it for a week, hose it out and then leave it hanging in the garage. As stated an oxy-acetylene torch up the end will clean it out real quick and you only need oxygen once you get it going. Do it at night for best effect and if you want mind altering effects do it inside with the door closed. It'll burn any finish off the pipe which is the big drawback.

I didn't think modern 2-smoke oils left much in the way of deposits. My MB100 commuter the few times I've looked has never had much of a buildup. The absolute best way to deal with this problem is to use the best oil you can afford and thrash the thing everywhere. :D

[Posh Tourer :P]

You can try the engine degreaser sold (perhaps not anymore I dunno) at the Warehouse at about $15 for 4 litres.... That is vicious stuff. Dont know on carbon, and it normally needs scrubbing to work properly, but it may do the trick if you leave it to soak. I use it heaps, it takes everything off including automotive paint, thick road grime, tarry bits if you really try hard, and brake dust too.... Brilliant stuff.. best cleaner I've ever used

[pete376403]

Stuff we used to use at GG&H for cleaning turbochargers was Tergosol - soak the item in that for a day or two, then clean off with water. Prolly not available anymore, bad for the environment, not safe for the kiddies, might leave a stain on the concrete, etc, etc.

[FROSTY]

I agree with the above posts --Pull the baffle out and blow it out with the oxy torch.
I would ask though --why is it so gummed up. I know the japs tend to err on the side of rich when setting the oil pump up. Maybee ya need to check its set up right now its run in.
I wonder too if yours is one of those restricted models with washers in the zorsts and restricted carbies

[beanz]

I don't think two strokes ever burn ALL the oil. So oil and combustion byproducts end up in the exhaust and stick to the side. Then the pipe heats up, and cooks the gunge, resulting in oily carbon crud on the sides of the pipes. I think its a normal thing, but yes, running rich wouldn't help either.

Can't imagine my RG150's ever had an exhaust cleanout. Its got about 3-4mm of carbon on the pipe intake. Gonna first try Oven Cleaner, then Drain Unblocker (both having Caustic Soda as their main ingrediant), then get onto the heavier shit if they don't work. Amping to try the oxy-acetaline method, but keen to kept the paint on too.

Seems Tergosol is a hardcore degreaser, which emusifies oil. http://www.tergo.co.nz/Tech%20Data/HTML/tergosol_a1.htm
Think we'rd need something more active to breakdown exhaustpipe carbon buildup.

[beanz]

And whats a "zorst"?

Exhausts? What are washers doing in there? :eek5:

[pete376403]

Seems Tergosol is a hardcore degreaser, which emusifies oil. http://www.tergo.co.nz/Tech%20Data/HTML/tergosol_a1.htm
Think we'rd need something more active to breakdown exhaustpipe carbon buildup.
Twas in a hot tank.But maybe it wasn't Tergosol, I was at GG&H some 34 years ago and a good few brain cells have been destroyed between then and now,

[pete376403]

And whats a "zorst"?

Exhausts? What are washers doing in there? :eek5:
Zorst pipe - gets the noise and smoke to the back.
Washers - restrictors to limit the power output by choking it up

[FROSTY]

And whats a "zorst"?

Exhausts? What are washers doing in there? :eek5:
oops someone already replied
but its a quick way to restrict a stroker -just weld a washer type restricter into the head end of the exhaust pipe.

[Racey Rider]

I ended up using the Caustic Soda approach.
Made up a strong mix in hot water, (250g/5L I think?), filled the exhaust, plugging one end to help keep it in there, and left it overnight. On emptying that out and giveing the pipe a good squirt with the hose, the Caustic Soda had removed maybe half of the Carbon. So I repeated it the next night. But that didn't give a much better result.
So the pipe went back on the bike with some carbon still sticking to the exhaust. After a day at the track I took the exhaust off again and was suprised to find it very clean. Seems the heating up and pressure of the gas flowing through it did the final clean up job after the Caustic Soda was used.

Hope thats helpful to someone.
Thanks for the advise.
Racey. :cool:

[Eddieb]

So after all that, does it go any better?

[beanz]

I'll give that a go, RaceyRider. BTW, where did you get Caustic Soda from?

[vifferman]

A couple of comments.

Firstly, the carbon / oil build-up will be from when the motor is cold and running at low revs, when relatively more oil is getting sucked in compared to air/fuel mixture, and there isn't the heat in the zorst so it tends to condense on the coldish parts. You'd get stuff all build-up if running at higher revs all the time.

Secondly, rather than just rinse the pipe after using caustic, flush it out with some vinegar and water as well, to neutralise the caustic. As acetic acid (vinegar) is weak compared to caustic, do a water rinse first, otherwise you'll need to use quite a bit of vinegar to neutralise the remaining caustic.
If you don't get rid of all the caustic, it'll be just sitting there, corroding things away bit by bit.

[F5 Dave]

Caustic soda (drain cleaner) is supermarket fodder. Dangerous stuff though, gloves & esp. googles -please.

The chemical reaction of adding water will cause quite a temp increase if you pour some on a damp rag if you need convincing how dangerous it is.

[beanz]

OK, cheers for that. Only thing that springs to mind, is that supermarket drain cleaner might not have a strong enough concentration of Caustic Soda to get that evil evil EVIL black goop out of the pipe. Will give it a go tho.

Also, I found a good doc dealing with how to mix the stuff up: http://www.osh.dol.govt.nz/order/catalogue/archive/corrosivechemicals.pdf

Worth a read before you end up dissolving your fingers. :doh:

[k14]

Thought drain cleaner was just sodium hydroxide? Or is that aka caustic soda.

[beanz]

Yep, Caustic Soda = Sodium hydroxide