Topic: 4 into 2 Exhaust

[Crimson750]

I want to replace my 4 into 1 exhaust for 4 into 2 exhuast. What are the considerations I need to make? Should I stay with the 4:1 or go with the 4:2? What do I need to do for jetting? Are there any compression/valve changes I need to make? What kind of preformance increase/decrease will I face when I do make the change? I'm figuring that this sort of setup will help make the engine breath a little easier, when  it exhales. Will I need to change the air intake setup? I don't really want to change to pods but I will if I need too. I'm looking for bits of wisdom from everyone...Thank you. Oh, my bike is a 1978 cb750 F3, but I'm also running a K8 in the frame as well.

[jdpas29]

i'm not sure, but i believe the 4-2 will have slightly more back pressure than the 4-1.  you shouldn't have to rejet to make this change.

[Crimson750]

What are the advantages and disadvantages between these two types of exhaust setups?

[8 Track]

A four into one gives you a little more power in the higher revs, at the cost of losing some in the lower revs.  Hondaman posted alot of testing info somewhere in the forum about different pipes that was very enlightening.  If I knew where it was, I'd link it to you.

[8 Track]

Found it! Read down to Hondaman's post and see if that info helps.

http://www.sohc4.us/forums/index.php?topic=5928.0

[Crimson750]

Awsome! Thanks.