2 Strokes...
As in motorbikes and not as in "who needs two strokes when it's usually over in ONE"...

My first motorbike - an '81 RD250LC. Had aftermarket expansion chambers (exhausts) with aluminium cans. These needed de-coking every couple of months. (And whilst it would qualify for this QOTW in it's own merit, soaking the aluminium cans in Cuastic-bloody-Soda is another story, damnit..!)

For those not quite up to speed on two-stroke technology (isn't that an oxymoron..?!), there are no valves in such an engine. So, as the piston pulls up and sucks... ahh sod it - wikipedia is your friend.... Expansion chambers work on creating back pressure from the exhaust to keep the fuel mix inside the cylinder ready for the next ignition.

You burn a fuel/oil mix which passes as burnt carbon and coats the inside of the exhaust which then needs to be cleaned out to maximise your power output.

The theory that I had heard was that to clean said carbon the bike shop would fill the exhaust (removed from bike) with acetalene and then light it. This got very hot very quickly and made a huge BANG which would dislodge the carbon. Quickly done but at a high $$$ cost.

There had to be a cheaper and quicker option for DIY cleaning, with something at hand that can burn quickly and give off a load of heat. Top of the class to those that immediately thought of Petrol..!

Thankfully for my own bottom-of-the-class-edness, methylated spirits first came to mind. And hand. Thankfully I DIDN'T think of petrol - because I poured nearly a LITRE of meths into the exhaust and gave it a good swirl to coat the insides and hopefully get into the oily, carbon deposits. Then I light it and get back...!

Hmm.. not at all explosive....exhaust's only a bit warm... can still feel meths swishing around inside. Starting to think about camp stoves now and just why this may now not work. Swirl around for a while and the liquid slowly dissipates in the heat. Thinking that it may have done the trick anyway, I prepare to give the exhaust a big blow of air to make sure the fire's out and maybe dislodge some of the soot.

As I suck back a huge lungful of air and lift the exhaust toward my mouth, I catch a glimpse of blue flame rushing UP the upturned pipe and the bastard backfires in my face...!!

Singed eyebrows and lashes and nose hairs. And a big face-full of black soot. EXACTLY like you see those cartoon caracters after looking down the barrel of a shot-gun!

And now you see why I was thankful that I didn't think of using petrol.


(Sorry about the length - must have been that extra stroke that put me off my stride..!)
(Sir Jester, Mon 24 Dec 2007, 3:58, 2 replies)

If you used petrol
Wouldn't you have noticed that it was still burning? Rather than meths, which has a near invisible flame?

This reminds me of the time I tried to separate the two parts of a tranga with my foot and ended up booting the thing several feet across a field and nearly set fire to a tent.

Smooth.
( Slippery Mick ‏, Mon 24 Dec 2007, 16:05, closed)

Help I'm on fucking fire!!
I can relate to the 'help me I'm engulfed in flames' part of this. Here's a photo of me playing with a propane burner in my buddy's basement. In this photo, I've noticed that, since I've just turned off the gas, and there's still a sputtering flame, shouldn't I just blow out the rest of the fire and be done with it?


And in the photo below, you get to see me in total 'my head is on fucking fire' mode, having just supplied the dying flames with much-needed oxygen.


Fortunately, it was just a flash and I escaped with little worse than singed eyebrow and bangs. Lesson learned I suppose. I've since gone on to try and kill myself in other ways, however...
( Heffrey wants to show you his wood at SmileMoon.etsy.com, Wed 26 Dec 2007, 3:49, closed)