Exhaust Isolators

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I am having a hell of a time keeping exhaust Isolators on my 73. I have gone through at least 4 sets of isolators in about 2000 miles. The original set lasted over 15000 miles!!! What in the heck is happening? Since the bike was restored, about 2 years ago, it has begun eating these things. I want to get the stainless set of exhaust mounting plates and some new isolators, but at this rate I am not so sure.

Are there any alternatives to mounting with solid components? If so, what are the consequenses? Is there any special techniques to use when putting on new isolators to keep them intact? Sure is becoming a pain in the posterior!!!


Thanks in advance!

S
 
I bought a new set from Norvil and one of them fell apart before I even got it completely on so I put on the old ones. I don't know if tou are familiar with McMaster Carr but they are an industrial supply house that typically has pretty good stuff and they sell ones that look just like the Norton ones. I can't attest to there's being any better than the Norvil ones but I'm going to try them next. Here's the link
http://www.mcmaster.com/#vibration-damp ... ts/=hnxw0j

Dave
 
My Combats eats up the best Brit kind to the best from Harley but I do extend their time a bit by reliving some of the shear load by waisting the buggers on a bench grinder. The heat oxidation factor gradually gets to them. If you get too tough/stiff cushions then you'll complain how soon the header bends fail.

Its a faulty design from the get go and should had support plates as 45' angle so a good part of the load would be in compression not pure hanging shearing. I have come to see the wisdom of Norton cheap wimpy header clamps, if they are snag fit then both the cushions [Lords Mounts] and the headers fail faster, so when loose to allow head to slip/slide in muffer some, its lasts longer. Clever little trick not in the manual as planned in function I must assume have tired to stop it stupidly prior to see error of my thinking logically on Commandos. Last week Trixie required the last one I had on hand.

On my special springs will suspend the muffler under a 45-ish degree hanger. Another special has 45' hanger the pipe more rest on cushions than hang.
 
steveyacht said:
.

Are there any alternatives to mounting with solid components? If so, what are the consequenses? Is there any special techniques to use when putting on new isolators to keep them intact? Sure is becoming a pain in the posterior!! S

Do not ever use solid mounts - the rubber is there to rock the mufflers in sync with the engine / gearbox shake. Solids will stress the hell out of the exhaust pipes and something will break ASAP. The OE rubber mounts should last years, and when fitted the muffler mounts should not be skewed, i.e. bent too far one way or the other.

Mick
 
Yr gottra hold the edge with vice grips :shock: or whatever , twisting the rubber tightening aint brilliant .

MINI ( B.M.C. ) exhaust mount rubbers , we're all told , std muffler shop stuff , in olde blighty .

HAVEING the ex. Mufflr aligned sitting say just up ( 3/32 in . ) from aligned , neutral , means the weights not tearing them up.
The idea being they LOCATE the thingo's , NOT Position them .The olde stress free aligned principal .bar the shakeing :wink: .

Ah well , it least its not the mufflers splitting . :lol: :wink:
 
Good time and place to ask how the guys who went with
brackets off the cradle to do away with the exhaust mount
problem.
 
I don't know if stuff here is about the wrong product being fitted the wrong way which leads to trying to find solutions to non-existant problems. Yeah, sure there's ways to improve anything but doing it the OEM way first for something simple like the exhausts is practical and economical.

Mick
 
What are exhaust isolators? Just curious. If they are the rubber rings on the triangular exhaust mounts I still have the originals on my 1975. I didn't think those things ever wore out.
 
I'm pretty sure they are talking about the rubber isolators that are used between the silencers and the frame on the Roadster, the early head steady mounts to the frame and the same thing from the silencer bracket on the S model from the dog leg bracket to the silencer as shown here.

Exhaust Isolators


I too have seen the McMaster ones and am thinking about ordering some because of the price. I've seen them used on Siemens mail sorting equipment also since I worked for the US Postal service and saw them. Look exactly the same.

Dave
69S
 
The fuel tank mounts are just rubber grommets. Agreed, there are a couple of part numbers for the isolators, but they all appear the same to me, except some are waisted and some are not. May depend on where you buy them. I bought a couple from RGM and one of them fell apart right away, they were even stainless.

Dave
69S
 
DogT said:
I'm pretty sure they are talking about the rubber isolators that are used between the silencers and the frame on the Roadster, the early head steady mounts to the frame and the same thing from the silencer bracket on the S model from the dog leg bracket to the silencer as shown here.

Exhaust Isolators


I too have seen the McMaster ones and am thinking about ordering some because of the price. I've seen them used on Siemens mail sorting equipment also since I worked for the US Postal service and saw them. Look exactly the same.

Dave
69S

That's what I thought. The ones on my 75 Mark 3 are still there from new. Should I worry?
 
As far as I've seen, they seem to last forever unless they break. But I keep a few around, kind of like gaskets.

Dave
69S
 
Yeah some are crap probably from the git go and others fail due to being twisted during tightening and being under strain.
I've seen the McMasters ones and want to try them too as they are cheaper but mine have lasted for years and I have needed to get any
 
"Onder" has a good point.

Some of the members here have fabricated alternative mounting brackets that bolt up to the transmission cradle, then make thier way down and around to the muffler mounting area.

This provides a secure mounting point that moves/rocks/vibrates in sync with the engine, where the other end of the pipes are mounted. The result is that you COULD mount the mufflers solidly without the same concerns for rapid damage, but I would still use high quality McMaster-Carr isolators to fully damp out the vibration at the heavy end.
 
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