Exhaust making info.

[Nudie]

I'm thinking about making an underslung exhaust/muffler. The actual fabrication I can do, but I've no idea about dimensions/flow rate/volume etc. Is it a matter of trial and error, or is there a hard and fast rule to apply? Or would I be better off modifying something that already exists?
I haven't got the bike yet, but I'm trying to get a plan together in my head for when I do. It will be an IL4 1000cc (never owned a 4cyl. Ridden a couple, but I've always had twins)

[ozzy1100]

I've never done one but I'd say what ever fits. If it was me I'd look at ones like what
was on venom. To be honest even if u drop a few hp any modern sports bike has more power than you can
use anyway....

[Nudie]

Yeh I wasn't sure if not getting it spot on would make it run like shit and I'd be chasing my tail with fuelling etc.
So much that I don't know.......

[megawatt]

Main thing is to try and keep the headers the same length.

[latheboy]

Try and keep the same Ø pipe that it has already.
Whatever you do, you should get it tuned after the work is done anyway.

Dyno runs before and after is always a good idea so you can see if you've made a huge stuff up, or it's the same or even better.

If OEM was 1" pipe and running good and you went to 3" pipe, it'll be LEAN as bro and run like shit.... also KABOOM. (pistons hot and melt etc)
If you went the other way, it'll be rich as bro and run like shit... also KABOOM. (oil gets washed off the bores from too much fuel so they wear quick)

The company that built the bike has spent a lot of money working out stuff like this. Coping what they have done is a good start.

[Nudie]

Thanks guys.

[Hagarr]

In my younger days hot dogs and make your own pipe was the only option as money was better spent on drugs and alcohol.

Later in life have been fortunate to spend money on proper name brand like Yoshi and Vance & Hines (takes less drugs and alcohol for same effect so $2 drunk now) and the like and in the case of the Yoshi with some airbox and other mods went from 156 RWHP to 177 RWHP on a dyno day that was 40 degrees in the shade so definitely better numbers but can't say I felt anything more in terms of HP just a bit smoother perhaps but when you're talking any modern thing such as Ozzy1100 has said probably in the real world won't appear to change the seat in the pants riding that much.

Just make it nice and loud thats all that matters :)

[Nudie]

Loud is easy. I'd just like it to attract a little less attention from the popo. I ride like a knob most of the time so I don't need help to get their attention!

[Crazy Man]

Are self built exhausts illegal?
What are the penalties?
I have read catalytic converters are not required for motorcycle ADR but removing them results in $5,000-$25,000 fine.

Please advice.


Also. From this thread I have gathered that:
1) Use the same diameter and length of header.

Does everything else have to stay the same or can you use larger diameter pipe to shorten the length of the exhaust?

[Azrael]

Are self built exhausts illegal? I doubt it, but they are fun cool and clever.

What are the penalties? Well it ranges from a simple decibel fine to anal rape depending on which state you live in and how pretty your arse is.

I have read catalytic converters are not required for motorcycle ADR but removing them results in $5,000-$25,000 fine. I read recently that some Italian guy is going to perform the worlds first human head transplant and while I think this is exceptionally cool I wonder how shit it would be to wake up with someone else's body and ruining the celebration by checking the size of your cock before shaking the doctors hand..

Please advice. Relax, except if the police are raping your anus, in which case relax is probably still good advice..?


Also. From this thread I have gathered that:
1) Use the same diameter and length of header. <-----yep, that's actually good advice.

Does everything else have to stay the same or can you use larger diameter pipe to shorten the length of the exhaust? No, read Latheboys last post


Crazy man, you need to work on your crazy..
that is all..

end

[hyofighter]

As always top advice is given . Read and learn or cut try if it fails cut change try again

[K6Thou]

Just hack fuck outta that exhaust.

What could possibly go wrong ?

[Crazy Man]

What is minimum wall thickness for exhaust? I have heard 20 gauge but 18 gauge is easier to find but weighs 38% more.