Checking Isolastic mounts?

Greetings,

Now that I have this Norton running good, I was going check the mounts. I've read the manual(s), both Norton and Haynes, searched the forum, and found a few tips. Here's what I've found. The front clearance seems good. However, I think someone put the shims for rear mount on the left. I can't get a feeler gauge in on the right side of the rear mount, but there's .010" clearance on the left. I can move the rear wheel side to side about 1/8", measured at the rear of the swing arm. The bike handles pretty good, the engine doesn't jump around at idle. The only thing I've noticed, is there seems to be a slight correction when coming out of a turn, It's not a shimmy, it's sort of like it corrects it's line.

Anyway. I plan to pull the gearbox this winter, it's kind of noisy, and will pull the mounts for closer investigation then.

Am I missing something?

Thanks for all replies.

I would check for movement between the swing arm and the cradle.

Cradle? There is no movement indicated in the swing arm bushings, if that's what you mean?

Have you checked the side to side ( fore and aft ) movement of the swingarm relative to the gearbox cradle,the swingarm pin wears the cradle and pivots sideways There are a couple of fixes for this if you search this forum .

HRD said:

Have you checked the side to side ( fore and aft ) movement of the swingarm relative to the gearbox cradle,the swingarm pin wears the cradle and pivots sideways There are a couple of fixes for this if you search this forum .

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Yes

10drum said:

I can't get a feeler gauge in on the right side of the rear mount, but there's .010" clearance on the left.

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Possibly due to the Iso. rubbers having become stuck to the inside the tube.

10drum said:

I can't get a feeler gauge in on the right side of the rear mount, but there's .010" clearance on the left.

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I had same experience. Cause was hardened and disintegrated PTFE washer.

Nick, I think that may be the case with this bike.

If you peel back the rubber dust cover and it’s full of particles that’s your answer. Unfortunately the rear Isolastic mount is the hard one to work on. If you only have to replace the PTFE washers and shim, it’s a lot easier than having to replace the isolastic rubber.

It is not all that bad if you have to or want to replace the original rubbers and spacers. Getting the big stud out can be tough but then the rubbers and spacers can be levered out and replaced without removing a lot of other big stuff. I prefer the original shimmed setup for this reason.
Get a lot of penetrating oil for the bolt and some stiff stainless brushes to clean up the inside of the iso tube of old rubber remains and maybe rust once you have the innards removed. Also the plastic washer material was changed and improved over the years. My '72 originals were a pinkish cream color but the later ones are much better and don't disintegrate.