Exhaust header supports? (2014)

A little off topic, but maybe we could use a laugh. While working at a Norton, Triumph, Bultaco, and Guzzi shop in the early 70's the hot setup was to do away with the Triumph baseball bat mufflers and replace them with what was called a shorty muffler. I think they were from Bates. They looked cool and added a little snort. They came with a chrome steel mounting bracket that was about 6" long with a hole at each end. The muffler had a threaded lug welded to it (bolt). This bracket (strap) was just about the right length to reach the bottom shock mount bolt. We would get the call from the owner saying that his bike was making strange noises when going over a bump. The worst part was having to tell him what the problem was without emphasizing the fact that he was an idiot.


Must have been this guy;


Exhaust header supports? (2014)
 
I welded a bracket to each head pipe which then connects each head pipe to a front motor/iso mount bolt.

All that leverage from the head pipe and muffler no longer is
applied to the exhaust port alone.

Downside is that the welded strap
captures the exhaust nut on the head pipe.
 
What kicker do you have on the bike? Looks nice and long.
 
What kicker do you have on the bike? Looks nice and long.

To be clear the pictures are not of my bike. They are pictures that were posted previously on the forum. I can't seem to find the original thread at this time so I thought to repost them for this discussion.
 
This may also be off topic but as i have suffered two exhaust header breakages in the same place on the same pipe , i have S type pipes and the left header splits at the weld as it enters the head , my ears pricked up when i saw the reference to crush washers , i have a plain steel washer , should i have crush or copper washers in there ? ,
all advice welcome , Colin
 
Exhaust header supports? (2014)

The header joints fail due to transverse bending action as the engine moves up and down mainly. There is shear load acting at the header's rear ends acting upwards I believe; additionally the header end / muffler joint is subjected to bending moments induced by vertical accelerations (road bumps, potholes). Gravity center of the muffler lies behing the support point I believe.

By transverse I mean transverse to the frame longitudinal-height axis plane.

In order to offload/preserve the rose joint, an intermediate bending-stiff support is needed consisting of a closed section (e.g., a pipe) bolted to the cradle similar to the flat tab shown. The header joint requires two ring clamps with bolts located in a 12 o'clock position and a connecting plate between them welded to the closed section (e.g., pipe). This arrangement would make the rose-joint bending-free and there would be a small nearly static load only acting on the rose joint. While this arrangement is possible at the far side, the primary cover gets in the way nearside, so I'd install the bending-restraint support to the front iso mount instead. In this location the two clamps should face "upwards" in a 12 o'clock position, i.e., in the longitudinal-height axis plane. The clamps will not be obtrusive IMHO.
The muffler support may have a harder life due to a possible increase in displacement amplitudes at the header/muffler joint. Restraining at the front iso mount should not alter the end displacements much vs. the stock configuration where headers are restrained at the cylinder head.

- Knut
 
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