Muffler Mounts (2011)

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Well the couple of Nortons I had with open headers were quick enough police could not catch us but do worry farmer might shoot at me scaring weight off their cattle or waking them up. Peashooters weigh ~6.5 lb, not counting the hangers.
 

L.A.B.

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Nater_Potater said:
concours said:
Those bracket plates with an offset... did you custom make them?
Nope, factory. This is an Interstate variant, if that has anything to do with it. The left side is straight/flat. I've always wondered about that myself, but the mufflers have always slid right on without any binding/misalignment noted.

Service Release N.81 (March 1972)

p.3

Kickstart foul on right exhaust pipe.
1972 Commando, Interstate and Interpol models only.
063132 Muffler bracket (triangular).
Distributors only.
An alteration has been introduced onto the muffler bracket to provide adequate kickstart pedal operating clearance.
The new bracket, which should only be fitted to the right hand side pipe is supplied under part number 063579.

Alternatively the existing right hand bracket may be re-formed as indicated below.
(Drawings of the modified bracket are included in the Service Release.)
 

Nater_Potater

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L.A.B. said:
Kickstart foul on right exhaust pipe.
1972 Commando, Interstate and Interpol models only.
063132 Muffler bracket (triangular).
Distributors only.
An alteration has been introduced onto the muffler bracket to provide adequate kickstart pedal operating clearance.
The new bracket, which should only be fitted to the right hand side pipe is supplied under part number 063579.

Alternatively the existing right hand bracket may be re-formed as indicated below.
(Drawings of the modified bracket are included in the Service Release.)
Very interesting! I assume this was corrected from the factory after '72, as ours was like this "out of the crate". Thanks for the history lesson.

Nathan
 

L.A.B.

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Nater_Potater said:
I assume this was corrected from the factory after '72, as ours was like this "out of the crate".
The service release is dated March 1972, so according to the wording, they were already fitting the modified RH bracket by then.
 

acadian

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Picked up the set of isolastics ordered locally from ackland-grainger. 50 durometer, not sure what the originals are, but these are noticeably denser. As with the other post, the stud is a c-hair long and required trimming. Also noted something interesting when closely compared with the old ones, the stud on the iso's received from a regular commando supplier are not integral to the outer plate. On the new ones the thread and plate are one unit. According to the specs given by grainger, these are bonded to a solid (not hollow) piece of rubber. Will be interesting to see if they do outlast the mounts we seem to be stuck with from various suppliers these days



 

Nater_Potater

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acadian said:
Picked up the set of isolastics ordered locally from ackland-grainger. 50 durometer, not sure what the originals are, but these are noticeably denser.
Good call! As noted back on page 3, I used McMaster-Carr's 60A durometer, and am now thinking 50A would have been better. Let us know if you notice any change in isolastic action, as mine seems to transmit more vibration at low rpms, and the "smooth point" moved up from around 2500 to 2800 rpm. 'Very curious to hear about yours.
Don't forget the new hardware, as I see yours are also course thread. This would preclude their use as tank mounts.

Nathan
 
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The common Harley variety is a bit more robust in density and width and back up plate similar to those shown above. I get more life out of these on head steady and silencers and header bends and rough surface isolation by 1/3 deep waist, expect for the ones that holds oil tank front mount and the under tank mounts. I gave up on resisting bouncing jouncing like strong but brittle tree in a storm for more flexible wealer palm trees in hurricanes.
 

drp

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I found some ones on eBay that have springs welded to the inside of the plates and the springs are encapsulated in rubber so they look just like the Norton ones. I was going to try these on my muffler mounts and see how they hold up. My current ones are fine so I haven't tried them yet. I also have found that I can buy the Harley ones, without the springs, dirt cheap at the local swap meet.

Dave
 

concours

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I've been running the soft silicone ones from McMaster, good durability and compliance so far
I’ve been using these, with a 5/16-18 x 3/8” bolt, so they clear the swing arm with no cutting.
4FE0C9E7-46E6-4D26-8D49-94FC2FA8A72B.jpeg
0604CC81-3906-4BA5-8B33-A188FCE96854.jpeg
 
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Did not hobot waist the spools at some point so there was more give? It isnt the life of the rubbers that matters but the life of headers and
exhaust ports.
 
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