[swearengen]

I'll apologize in advance for my lack of knowledge. So I understand that a free flowing exhaust can be good so long as the fuel map is correct. I also know back pressure matters, not sure I really know why. Now for my question, I have an almost brand new Akrapovic exhaust from a 300 cc bike. If it physically fits or I can fabricate the connection would it be a bad idea to use it? I guess what I'm wondering is do manufacturers really design and test their canisters against each bike or do they often reuse the canister?

Thanks!

 

[Mr Mike]

I'll apologize in advance for my lack of knowledge. So I understand that a free flowing exhaust can be good so long as the fuel map is correct. I also know back pressure matters, not sure I really know why. Now for my question, I have an almost brand new Akrapovic exhaust from a 300 cc bike. If it physically fits or I can fabricate the connection would it be a bad idea to use it? I guess what I'm wondering is do manufacturers really design and test their canisters against each bike or do they often reuse the canister?

Thanks!

Hi swearengen welcome to the forums... There are a couple people on here ( me not included ) that can answer that question and with a good amount of knowledge in that area.

Back pressure is absolutely important on 2 strokes, I am not all that aware how much importants it plays with four strokes, except more is a bad thing for fuel economy is what I've read - but don't quote me.

I doubt they make a whole new system for each bike, I bet they Re-dress the old style pipes & create new attachment to affix it to a new bike. the catalytic converter on the 400 already supplies some restriction to flow, every thing past that is pretty much for sound mitigation is my understanding.

I wouldn't try to put a moped pipe on a 400 but you could easily try a 250 or 300 pipe, and I bet it work fine.

 

[Kiwi Rider]

Mr Mike is correct, there is lot of generic design with slip on's.
I put a Delkevic CBR250 Muffler on my CBR300 and it ran sweet as a nut.
What's more important is getting someone to dyno tune your engine to suit what ever muffler you do decide to put on.

Back pressure creates a return pressure wave that has a scavenging effect ie. it helps draw the exhaust gasses out of the cylinder therefore increasing efficiency . Usually this effect helps improve low to midrange power. Maximum HP gains are generally achieved by a freer flowing system but you have to tune your fuel map to suit.

That's not to say your bike won't go OK with the 300 exhaust, just depends how far you want to go with getting the full benefit of it.

 

[swearengen]

Thank you both. I really appreciate you taking the time to help out. So it sounds like ideally regardless of exhaust a fuel controller and a shop with a Dyno would be in order. Do you guys have a preferred fuel controller?

 

[Kiwi Rider]

Thank you both. I really appreciate you taking the time to help out. So it sounds like ideally regardless of exhaust a fuel controller and a shop with a Dyno would be in order. Do you guys have a preferred fuel controller?

Most people are going with ECU flash tuning rather than fitting a piggy back fuel controller these days.