H pipe

[bacongrease]

 What was the OEM crossover purpose ? What did the H pipe improve?
04 Stone I bought  from  next door neighbor came with an extra H pipe and mufflers,  in addition to 3  extra wheels, seats, etc. He just dumped everything.

Both H pipes look  identical. He did about all the upgrades,  apparently cutoff the back of the mufflers to remove packing?

[rocker59]

H-pipes improve mid-range performance and reduce noise by letting each exhaust breath through two mufflers.

[bacongrease]

  So the OEM did not allow for The scavageing effect.

[Vagrant]

Clarification for a new guy. The bike came with a massive, heavy, quiet H pipe more commonly know as the "colostomy bag".  When installed with stock pipes the bike had great mid range torque and was quiet, although you had to pull the mess off to drain the transmission fluid on the 1998-some99's. Then there was an aftermarket H pipe sold that let the engine breathe better and rev quicker but you lost some mid range. It was the same diameter all over.
Post pics.

[Gliderjohn]

For what it is worth when my H pipe burned through on the T-3 I didn't replace it and have not been able to tell any difference.
GliderJohn

[dguzzi]

   so then why a crossover in front and under the center (like a hydro has)?

[Wayne Orwig]

   so then why a crossover in front and under the center (like a hydro has)?

The hydros have a nice bump in low RPM torque. Not saying that crossover is the reason, but I kept it there even when the crossover cracked and I had to repair it.

[dguzzi]

  Me too, and the po did too.

[Two Checks]

The placement of the x-over determines the rpm at least which breathing is improved. Close to the cylinders, upper rpm. Back in front of the mufflers, midrange. Both-best of both worlds.

[John A]

The placement of the x-over determines the rpm at least which breathing is improved. Close to the cylinders, upper rpm. Back in front of the mufflers, midrange. Both-best of both worlds.

Ace told me that when he tried it on a dyno,  a front crossover  and an h pipe gave the best results and he considered it worthwhile to have both. I put both on my Bassa and I believe he is right

[Dilliw]

Stock crossover cracked pretty early (cheap metal) and one of the front crossover welds failed too.  I replaced the middle one with a Stucchi and it eventually cracked as well. 

I ended up with one of the "never crack" H Pipes that were available for a while  It's two pieces like the front one that allows it to slip in the middle some.  I also removed the clamp from the middle of the front crossover at the suggestion of someone here.  30k later problem is still solved.  I

[FarmallA]

If you want to understand exhaust systems, here's the best reference.  I read this many many years ago.

http://www.bentleypublishers.com/automotive-reference/engineering-and-motorsports/scientific-design-exhaust-and-intake-systems.html


FarmallA
Steve

[John A]

If you want to understand exhaust systems, here's the best reference.  I read this many many years ago.

http://www.bentleypublishers.com/automotive-reference/engineering-and-motorsports/scientific-design-exhaust-and-intake-systems.html


FarmallA
Steve

This^^^^^
A lot of the testing is done on a single cylinder 500cc engine