The exhaust on the Black Horse was a bit loud to say the least. Basically it is a 2" bore stainless tube with an 1-1/2" bore pipe, full of 3/8" holes and wrapped in wire wool with reducing mute, inside. A reducing mute is also inserted in the top of the outer tube.
Today I decided to see if I could improve it's silencing qualities.
At the top end of the inner tube, a ring is welded. This acts as a spacer between it and the outer tube. Four equally spaced tack welds hold it in place. First I cut out the ring between the welds and the end was blanked off instead of the mute.
I only had enough wire wool to wrap the inner tube in, for half its length. Searching for something non-flamable/heatresistant, I found a box containing a roll of fine, stainless mesh. The type that is fitted to soffits on houses over ventilation holes/slots.
This was wrapped in layers round the bottom half of the inner pipe and then all re-assembled. Lastly, the reducing mute was re-inserted into the top of the outer pipe and rain flap re-fitted.
Idle and low rev running is a pleasant, low pitched beat. Also, when the flap is closed, the whistle it produced has gone. High revs, which had a rather ear shattering, strident pitch, now have a slightly subdued, mellower sound.
I reckon if the whole length of the inner pipe, was wrapped in the stainless mesh, then it woud be even queiter at high revs.
