Rookie Exhaust Effort

[denisducati750]

OK so I’ve started my exhaust effort again by hopefully fine-tuning my MIG use as well as investing in a really solid hacksaw for curved cuts and a bench-mount style angle grinder for cleaner straight cuts. The header pipes are all cut and ready for tack welds and my pro mate will weld the finished joins.
Question now is this - the header pipes you see in the photo are 38mm (inch and a half) pipe. They’ll go into a Y joiner made out of 38mm pipe I’m hoping to make up tomorrow as a 2 into 1 merge, then run back under the right hand side and up to to a single muffler - at this stage a Harley Sportster muffler. The frame is fairly low to the ground so road clearance would be an issue running pipe under right side of engine. Am I better to run 38mm pipe all the way to the muffler - or is there an advantage in going up to a 45mm single pipe from that Y merge to the muffler?

 

[TwoManyXS1Bs]

... The frame is fairly low to the ground so road clearance would be an issue running pipe under right side of engine...

Run the header pipes into a flattened "Y" oval?
Maybe some ideas if you Google "flattened exhaust pipe"...

 

[denisducati750]

Thanks mate that’s something I hadn’t thought about. Here’s what I’ve ended up with today - ready for either a 38mm or 45mm single pipe out of this Y merge.

 

[denisducati750]

Here’s a wider shot of today’s effort - is really happy with the way it’s looking - something a bit different like the rest of the bike - she’s a ‘Bitza’ with a bit of everything!

 

[TwoManyXS1Bs]

Do you have a disassembly strategy in mind?

Don't want to paint yourself into a corner...

 

[gggGary]

Rut roh!

 

[TwoManyXS1Bs]

I have this touchy spot about twisty/complicated exhaust systems.

Back when I built my V8 Vega, I used a Don Hardy header kit. Large equal-length primaries, no body or fender cutting, it all managed to fit into that tiny engine bay.

Barely.



6-piece header system, you have to assemble it in stages as the engine is lowered into the bay. One of the most challenging Chinese puzzles I've ever done...

 

[xjwmx]

Some cars rusted into dust and you never see them now.

 

[easyrider69]

Zat flux core MIG? gotta go gas, just sayn' Design, cutting and fitting looks great!
Um, the welds? not so much, add lots of heat or slow down the feed. Do lots of practice on thin scrap first. You want plenty of heat and penetration. Control melt outs by keeping "on time" short. Weld, stop, let cool till the red goes away looking through the shield, repeat. A much easier process if you aren't constantly chipping slag.

Use sugar and water ,lots of sugar about 1/4 cup per litre in spray bottle before you weld , will prevent splatter. Nice fitting job going to be starting mine soon too