Welding Tips and Tricks

Hello from Australia.

Everyone calls me Lozza, I mainly weld motorcycle exhausts (2 stroke expansion chambers) for fun and a hobby. I will be looking to improve my aluminum welding as I don't do enough of it. Also want to get a good internal purging set up to do Ti.
Cheers

Hey mate,

Welcome along. Another Aussie. Win.

Mick

Great to have you aboard.

~John

Welcome to the forum. Post some pictures for us to see.

Is this a conspiracy...Aussies are taking over.

Superiorwelding wrote:Welcome to the forum. Post some pictures for us to see.

Is this a conspiracy...Aussies are taking over.

You never know what those Aussies are up to. They might be trying to take over the Forum.
~John

Cheers here are a few random pics





Segments were laser cut with these pipes, the seam fit was so good it was actualy harder to weld, with a bit of heat the seam would disappear

Lozza,
WOW! that is allot of fit up and careful measuring. Do you have any pictures of assembly?

The metal is the easy bit making the templates is the tricky bit, I make a 3D template from cardboard (and sticky tape) so I can check clearence of kick starts and fairings. I don't have any pics of that but just imagine the pipe in cardboard

How do you work out what will work for a certain model of bike?

Welcome to the forum Lozza.

I know this is off topic but since we have all the Aussies right here, anyone of you go to the Summer Nats 2014? I would love to fly over one day to go.

I might have said this before but Headers/Exhaust is a interest of mine. I would love to have the chance to build a set. Maybe I will get a few pointers from you?

Hey mate,

Im not much of a car guy, happy to look and learn about welding mods on them rather than do it my self....cheaper that way.

I know a few petrol heads, one guy has a burnout car that he competes in. Nothing like the full on blown beasts you see around but its a start.

Mick

I love your lingo...petrol heads...I will share that one at our next car club meeting. I wish we had the burn out cars you have there. Maybe if I run into a chunk of money I can build one
Cheers (if I am allowed to say that)

2T Institute wrote:Everyone calls me Lozza, I mainly weld motorcycle exhausts (2 stroke expansion chambers) for fun and a hobby. I will be looking to improve my aluminum welding as I don't do enough of it. Also want to get a good internal purging set up to do Ti.

Hi, Lozza.

I've seen these exhust mods before, but maybe I'm the only guy here that doesn't know what they're for. I tripped across a guy on YouTube who'd done this to a chainsaw, which made it sound like a dirtbike.

Does the expansion chamber also improve performance of the motor, or just the sound? When designing, do you have a way to predict the effect, or is it just best guess?

Cheers,
Richard

Oh the black art of strokes tuning,
I've built a lot of 2 stokes but never ventured into expansion chamber design
My basic understanding is they are tuned lenght , because 2 strokes don't have valves they use returning exhaust plus to push the full mix back into the combustion chamber just as the piston closes the exhaust port,
And depending on how long and how wide the pipe is determines where the power and torque Are in the rev rang.
Again I know nothing it's a black art preformed usually buy old men with extremely powerful beards,

Hey,

Dont forget Rev Head. There is a song about it.

http://www.youtube.com/watch?v=6uoOeMys ... rTTf0Rz_hs

On the plus side, you dont need a lot of cash to have a burnout car. Just get an of 6 cyl junker disconect the back brakes and let her rip. When she blows up or blows the tires, change em out or junk it. Fun times.

Mick

weldin mike 27 wrote:How do you work out what will work for a certain model of bike?

the engine and the rpm you want peak power at, the rest is the laws of gas dynamics, which is like the piano accordian, ie if you know about gas dynamics your obliged NOT to talk about it.

Superiorwelding wrote:I love your lingo...petrol heads...I will share that one at our next car club meeting. I wish we had the burn out cars you have there. Maybe if I run into a chunk of money I can build one
Cheers (if I am allowed to say that)

Royalties are involved if you reside outside Australia

RichardH wrote:

2T Institute wrote:Everyone calls me Lozza, I mainly weld motorcycle exhausts (2 stroke expansion chambers) for fun and a hobby. I will be looking to improve my aluminum welding as I don't do enough of it. Also want to get a good internal purging set up to do Ti.

Hi, Lozza.

I've seen these exhust mods before, but maybe I'm the only guy here that doesn't know what they're for. I tripped across a guy on YouTube who'd done this to a chainsaw, which made it sound like a dirtbike.

Does the expansion chamber also improve performance of the motor, or just the sound? When designing, do you have a way to predict the effect, or is it just best guess?

Cheers,
Richard

According to Jan Thiel probably the greatest ever two stroke tuner (no beard BTW) a pipe is responsible for about 2/3 of the output of a 2 stroke engine. There are various simulators that can help you arrive at a final design, I made the stupid mistake of asking Jan what simulators he used when he was at Aprilia Corse (he was responsible for the highest ever output from a 2 stroke that is 440hp/litre) he just said "None, it was all be trial and error" but with a hefty 30years of experience and help from a his friend Frits Overmars to do the thermo dynamic calculations.
Here is a chainsaw I did earlier