Honda CB750 Sandcast

Tube rubber muffler between silencers

jaka · 12 · 3200

jaka

  • Newbie
  • *
    • Posts: 20
    • View Profile
Hello!
The tube rubber muffler (as per CMS i Holland) that sits between the silencers at the back ,is it just holding the silencers together in some way or is it guiding exhaust gases between the silencers?


acruz

  • Full Member
  • ***
    • Posts: 115
    • View Profile
great question.  When I run my CB750, I can feel exhaust gases from the one or the other pipe.  I think there may be a small amount of gas exchange between the upper and lower exhaust through that connection.


kp

  • Administrator
  • Hero Member
  • *****
    • Posts: 1806
    • View Profile
air pressure balance, Bernoulli's principle relative to air/exhaust flow. Well that's my understanding
Yabba Dabba KP


Sam

  • Administrator
  • Sr. Member
  • *****
    • Posts: 397
    • View Profile
Air pressure balance and exhaust alignment. Though, the rubber bushing is never enough to force the exhausts into alignment. For stubborn alignment issues, Yamiya has been supplying little pipes that side inside the top and bottom exhausts to align them. The rubber bushing hides them of course. They work well.
Ujeni Motors
Sandcast #410
Sandcast #538 Watch the restoration!
Sandcast #6592 All original daily driver.
Diecast #16608


Sgt.Pinback

  • Hero Member
  • *****
    • Posts: 695
    • View Profile
Never seen those but thats sound to be a good solution.
Cheers, Uli (Leonberg, Germany)


jaka

  • Newbie
  • *
    • Posts: 20
    • View Profile
Hi!
I made two thin wall steel tubings like SAM spoke about to align the silencers . -Strange that Honda did not do that from the beginning. Just thrusting a rubber grommet isn't that convincing.


jaka

  • Newbie
  • *
    • Posts: 20
    • View Profile
Hi!
Here is a picture!
23mm outer diameter with a flange in the middle.


Sam

  • Administrator
  • Sr. Member
  • *****
    • Posts: 397
    • View Profile


Sam

  • Administrator
  • Sr. Member
  • *****
    • Posts: 397
    • View Profile
Be careful. If you plan to ride the bike, plain steel will rot super fast.
Ujeni Motors
Sandcast #410
Sandcast #538 Watch the restoration!
Sandcast #6592 All original daily driver.
Diecast #16608


jaka

  • Newbie
  • *
    • Posts: 20
    • View Profile
They ar easily removed so do not think that is a problem.
I copper plated one though, that could perhaps prohibit rust.
Thin copper plating is easy to do on steel, I just put on"rust eater", and at the same time brush the steel surface with a copper brush then wipe away  remaning residue with a cloth.
« Last Edit: November 03, 2020, 09:13:08 am by jaka »


Don R

  • Full Member
  • ***
    • Posts: 233
    • View Profile
 My thought was the little metal tubes were there to encourage me to align those exhaust nipples before tightening anything else. I've put on 3 sets and all went on well even when I had to adjust the pipe at the head with a rolled up towel and a rubber mallet.