De-carbon 2 Stroke exhausts

[pete376403]

And whats a "zorst"?

Exhausts? What are washers doing in there?

Zorst pipe - gets the noise and smoke to the back.
Washers - restrictors to limit the power output by choking it up

[FROSTY:Me]

And whats a "zorst"?

Exhausts? What are washers doing in there?

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.

[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/cat...echemicals.pdf

Worth a read before you end up dissolving your fingers.

[k14]

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

[beanz]

Yep, Caustic Soda = Sodium hydroxide