[daktah]

finally getting around to replacing my rusty gutted """mufflers""", but i go to take them off and the ends turned to dust and the parts that go in the crossover are rust welded in there and not coming out. this brought me to the decision its not worth the hassle and im just going to scrap it and make my own crossover since i have a welder and chopsaw just collecting dust anyway.
should i go for an h pipe or x pipe? obviously the h pipe will be far easier, just pop a pair of holes and weld a pipe on them, but would an x pipe give any noticeable gains over an h pipe?
also should i keep it at 1.5 inch as the headers are or up it to 2/2.25/2.5 inch?

 

[J-T]

Not sure how helpful it will be with your decision but have you seen this?

http://www.hondatwins.net/forums/67-miscellaneous-discussion/41350-power-chambers-explained.html

 

[daktah]

i have, the chamber acts sort of like a mix of an h pipe, collector, and muffler. it also came about in the very beginning of the implementation of exhaust scavenging so id imagine a more modern style of crossover would be equal or better to the chamber. i dont know though if an x pipe would give much of an advantage over an h pipe to warrant the extra work in making it.

 

[longdistancerider]

One of the key things about the chamber is it increases the primary pipe length which helps in low/mid range power. An H pipe serves more as a balance tube, little effect on alternate scavenging of the opposite cylinder. The X pipe does work for scavenging.

 

[daktah]

so basically I would be required to make an x pipe if I don't want to lose power then

 

[longdistancerider]

We're probably talking in the neighborhood of 1-2 HP, not a lot but we've only got 43 to start with when everything is spot on.

 

[daktah]

yeah exactly, hey who knows a properly made x pipe might even give an extra pony or two from the added scavenging and reduced restriction?

 

[longdistancerider]

I'll measure my 2-1 pipes tomorrow to give you a good idea of the length you're after for the X

 

[daktah]

thanks!

 

[longdistancerider]

Measured from the flange, pipes still on the bike, they measure out to 31". That's the longest they should be. Measured from the flange face that mates with the head the shortest measurement is 31.5" for a 400cc engine. 450's are longer pipes.

 

[Old Okie]

I jumped on e bay and found an H-Box for my '79 CB400T II
for about $35.00, shipped. It is in very good condition. I can not help but believe
that the Honda engineers are better at designing exhaust systems than I am.

 

[daktah]

yeah but where's the fun in that?

 

[longdistancerider]

Honda spent a lot of time and research to get that unit correct, I read somewhere that this one part was a 2+ year and multiple designs project.

 

[Old Okie]

The fun is...having a bike that runs as it should under most conditions.
For the most part you can do about whatever you want, after the H Box.