Custom exhaust construction?

[CookMySock]

Is anyone playing with custom stainless exhausts ?

I'm tempted to get some bends, collars, and springs, and make up a different exhaust, just to be, er, different. Maybe set up some rollers to turn out megaphones too.

For a vtwin, whats the situation leaving the crossover out - one pipe per side, per cylinder? Unwise?

Steve

[The Pastor]

the cross over balances the flow, i think. Older bikes have them, not sure about modern ones,

Harleys i think dont have them.

[AllanB]

I'm building a pair of mega slip-ons in mild steel for my Hornet - see my blog for progress - Stainless will be the same just dearer for the raw materials.

A cross over pipe is often used to balance the exhaust and 'borrows' both mufflers. I read somewhere on vertical twins it was often used to smooth out the engine a fraction.

Mucking around with the headers will make a bigger difference in tune on your bike than the final muffler - I'd stick with very close to the stock internal diameter and approximate length - this way you won't be mucking up the existing engine characteristics and you can go for a different look.

[avgas]

a crossover will generally give the engine a better balance - but is not required. Usually the best bet is a balance tank where exhaust holds the same pressure.
4 strokes will run with anything - including no pipe at all.
If you want the sound - go for separate systems, if you don't care....put a balance in.

[nallac]

the cross over balances the flow, i think. Older bikes have them, not sure about modern ones,

Harleys i think dont have them.

most harleys have em,its just that the newer ones are better hidden/don't stand out like dogs balls like the old ones....

[CookMySock]

Cool. Any comments on "silencer"(sic) construction, that amplifies the low sounds? I like a bit of thunder now and then..

I should probably stick with mild steel and the MIG to start with. Cheap!

Steve

[zx rider]

I had a SV650 and found that the conector is very important, as is the total length of the exhaust. Micron says 90 inches of total length (add the 2 headers and muffler) is needed for pulse tuning. The Y is needed to scavange the other cylinder (in turn). The pipe dia' is responsible for back pressure and gas speed. Too big and the gas speed slows down= motor won't rev. Get it wrong and you will have no torque and all hp, or vice versa. Oh and fuel economy will be shot too. This is a science, so tread carefully eh.

[FROSTY]

On the SV650 . The headers and balancer really were the important part of the exhaust. The muffler seemed to make sod all difference

[meowmix]

Exhaust theory is an interesting one...
If you're going for looks mainly, I'd simply measure the internal diameters, lengths etc. and replicate it. You may be able to get away with slight variations, e.g. a very slightly larger diameter, shorter headers etc. it should be pretty much ok, just need a little jetting possibly.

If you want something that changes the exhaust characteristics drastically, there is alot of information out there, but generally even for racers its down to trial and error, and therefore deep pockets. These sites are pretty good:

Wallace Racing (http://www.wallaceracing.com/header_length.php)
Nightrider (http://www.nightrider.com/biketech/calculations.htm)