Planning an exhaust design

[psych0hans]

Hi guys, I'm planning on designing an exhaust system for the 390 series bikes. My goals are to : -
1) reduce weight.
2) make sure that the power/torque does not change for the worse.
3) Maintain the stock mounting positions.
4) reduce heat emission from the exhaust to the rear shock.
I was thinking of gutting the stock exhaust and creating a flow similar to the stock exhaust, basically similar to de-catting the stock exhaust and reducing weight at the same time. Any suggestions would be greatly appreciated.

 

[Old3]

I'm surprised nobody has laid a muffler under it with a forward side exit like a few of the Buells had.

 

[Hekimpd]

That's a good point. I didn't think about that till you just mentioned it.

 

[psych0hans]

I'm surprised nobody has laid a muffler under it with a forward side exit like a few of the Buells had.

Pics please? Or any link?

 

[Old3]

Like this.

 

[A1VW2NV]

Because it looks like shite!

 

[Andy]

What's wrong with the tried and tested pipe exiting out under the engine and up the side ending with a silencer?

 

[DCMoney]

Like this.

Racers need a belly pan.

 

[Old3]

It's a street bike for me, and I'd rather have the weight under the engine. That routing gives you room to choose header length and a long muffler if you desire, to keep it quiet.

Id also have preferred more fuel where the battery is and the battery down in front of the crank. Lots of dead space there and they used that spot on the 950 Adv. that had great packaging. This thing is probably a gallon light in capacity for no reason.

 

[psych0hans]

Hi guys, just a small update, I've decided to try two designs and should begin work on them this coming week.
1) This will maintain the stock exit location, will have baffles, but no cat and will hopefully weigh a lot less than the stock system. Not too sure about the power output, but I'll be keeping this as close to stock as possible.
2) This will be an under seat design, with an expansion chamber fitted, like the arrow and akra units. Not sure how exactly I'm going to design this, but I'll be starting the work coming friday, I think...

I'd love to hear your views on the same and any suggestions you guys might have.

 

[Diploman]

I think the secret to the nearly-unbeatable power output of the - admittedly heavy and bulky - OEM exhaust is the carefully-calculated tuned length of the exhaust path. Whatever system you design, I suggest you measure the OEM exhaust path length from cylinder head exhaust port, through all the interior convolutions of the exhaust to the outlet. Then duplicate this length on your new design.

 

[psych0hans]

I think the secret to the nearly-unbeatable power output of the - admittedly heavy and bulky - OEM exhaust is the carefully-calculated tuned length of the exhaust path. Whatever system you design, I suggest you measure the OEM exhaust path length from cylinder head exhaust port, through all the interior convolutions of the exhaust to the outlet. Then duplicate this length on your new design.

Thanks for your reply, that's basically the idea, I have a spare exhaust to cut up so measuring the volume and length will not be too difficult. Raw material is most likely to be either mild steel or stainless steel with ceramic coating for trapping the heat. This should prevent the exhaust from cooking the shock.

 

[Deleted member 452]

I've been looking into building one, too. I believe I can fit a 4.5" can that's 10- 12" long without using a tip that exits to the side. This size muffler that points down should be a little quieter than Competition Werkes without hurting performance. I've also researched who builds the best muffler cores and this is my choice for lightweight noise suppression:
Custom and Universal Exhaust Systems - Area P :: No Limits

 

[psych0hans]

Have started work on the exhaust, will be fabbing a fixture to ascertain the mounting points, before proceeding to cut the s**t out of it to study the internals.

One thing I'm genuinely concerned about is that there is a bracket which bolts onto the stock exhaust which holds the bottom fairing. How do you mount this bracket with an aftermarket exhaust? Or do you just leave it out?

 

[Hypoint]

How is it coming along?

 

[Deleted member 452]

Hey Psych0Hans,

I think I've seen you post that you were also working on developing some triple trees and wheels for our bikes- Any updates on these products?