I removed the front isolastic unit on my 1974 850 Mark II. The rubber mounting bushings on both sides are mashed in. The red pencil lines show the gap between the edge of the rubber and the lip of the mounting cylinder. Should I think about replacing them, or is this somewhat normal?
Is this isolastic rubber at end of life?
- Thread starter Pete_B
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yes, you could use some new rubber snubbers
HOWEVER, you could just rotate those oblonged outside rubbers 180 degrees so the sag is taken out..
with luck you can just grab the inner bush with a pliers and rotate them
but, assuming your rubbers are now some 40 years old you may consider getting new ones
and also a set of the threaded quicky turn adjusters to replace those pesky to get right shims
the front iso is very easy to take off, clean the tube out, and put in new rubbers
the rear iso definitely can be done in the frame with very little removed and just a couple of hours fiddling
HOWEVER, you could just rotate those oblonged outside rubbers 180 degrees so the sag is taken out..
with luck you can just grab the inner bush with a pliers and rotate them
but, assuming your rubbers are now some 40 years old you may consider getting new ones
and also a set of the threaded quicky turn adjusters to replace those pesky to get right shims
the front iso is very easy to take off, clean the tube out, and put in new rubbers
the rear iso definitely can be done in the frame with very little removed and just a couple of hours fiddling
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Traditional poor boys would just flip em but I'd call em shot and have ya send them to me. Just spriz your favorite penitent all around for luck then get a stout wood drift and smack the living daylights out on the shaft for a shock wave to move to break the bonding crust or move them a good ways 1st strike and repeat till out. Ya could try to slip something around to break adhesion but I found that just add an extra unneeded step as they can still be a bugger to bump out. They are quite well attached to the tube. I install exactly the same after prior nice guy methods, POW To The Moon Alice. Smear with about anything vasaline to sillycon grease, don't really matter as long as don't rust again as no off the shelf solvent or lube will attack these cushions but oxygen and maybe acetone or brake fluid.
Thanks Pete.V. I'll try the P-80. Never heard of it before. Yes Dennis, that's me with Norton Number One. Photo taken in 1974. I still can't forgive myself for selling it. Anyway, I recently acquired Norton Number Two. I intend to enjoy this one until I'm too old and feeble to kick start it. 
Pete_B said:Thanks Pete.V. I'll try the P-80. Never heard of it before. Yes Dennis, that's me with Norton Number One. Photo taken in 1974. I still can't forgive myself for selling it. Anyway, I recently acquired Norton Number Two. I intend to enjoy this one until I'm too old and feeble to kick start it.
Go here. http://www.ipcol.com/shopdisplayproduct ... Lubricants
They'll send you all the sample you ask for which for us is a life time supply.
DogT
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Like others say, no special tool, but the old ones may be stuck to the tube which will require some cleaning. That said, I removed my year old ones to install the Hemmings adjusters and found the front donuts had already taken a 1/4" or so set to the bottom. So I flipped them while I was there. If I had the gumption, I'd do the comnoz tribblewhite spring below the engine, and then the ludwig rear wheel adjusters, and then.......it never ends. Actually I don't mind the bike in it's pretty much stock looking shape.
Dave
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Dave
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Pete_B said:Thanks Pete.V. I'll try the P-80. Never heard of it before. Yes Dennis, that's me with Norton Number One. Photo taken in 1974. I still can't forgive myself for selling it. Anyway, I recently acquired Norton Number Two. I intend to enjoy this one until I'm too old and feeble to kick start it.
Parallel lives. I had number one in 75/76 and let it go too. I can't find any of my old pictures tho. Number two will be around till I can't breathe anymore...if I can't start it I will bring it in the living room so I can look at it while I watch TV.
I used a long piece of thread rod through middle tube with a socket at one end as a spacer so it pushed on rubber not the nut against the tube. At the other end you have large tube, socket or large box spanner anything bigger than ISO tube to give you a space to pull it into then thick washer or bar with hole to past rod through but bridge tube. Put a nut on an as you tighten it it pulls the rod through an the rubber out.
No hammering an if you wrap rag between ISO tube an pulled tube you don't even damage the paint. You can reverse the process to fit new bushes with suitable rubber lube applied.
Hitting them means much of your effort will be cushioned by the rubber this method means you can put large amounts of force through the rubber with constant pressure an little effort on your part. I have the special tool but don't use it as this method works better.
No hammering an if you wrap rag between ISO tube an pulled tube you don't even damage the paint. You can reverse the process to fit new bushes with suitable rubber lube applied.
Hitting them means much of your effort will be cushioned by the rubber this method means you can put large amounts of force through the rubber with constant pressure an little effort on your part. I have the special tool but don't use it as this method works better.
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Get a haircut.That's what my dad said. Got to dig out my big hair pics and learn to post. Prise out the rubber. you will fing the limiter rubbers have turned to dust or at best slopping - about things on a rusty support thingy tube. :| If you don't want to upgrade to vernier I believe earlier style rubbers are slightly softer and better. I.M.O.
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I did 2 sets of rusted and mooshed off center iso's and found if ya smack the shaft hard enough it pops most the way free or in at once then can boop some more to fine tune. Nothing wrong with puller of course but there's no down side to the hoboto hammer. After some years reading the various testing of various grades of cushion elasticity and the common compliant of isolation taking to upper 2000's lower 3000's which can be too dam fast for conditions, I tried 45" bench grinder bevel on fronts leaving ~1/4 flat contact area to find worked a treat of low threshold isolation yet handling good as any on my un-tammed Combat and I pretty dam sure better than anything else on my tammed Combat. I enjoy flying carpet onset in lower 2000's on both Combats. Your call to follow the crowd or not.
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Real interested in bevel cut but tiny man balls and terror thoughts of handling in sweepers kick in. But the goal is to cut vibrations lower without sacrificing safety and handling for sure . most of us don't run tri-linked system to compensate for the flexings like Ms. Peel sexy-doms.
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