Isolastics - again

I looked at prior posts about Isolastics, but with 113 entries, I tired of the search after a few pages. I have a 75 MK III. It was an eBay find I have no idea how many miles the bike has on it or any prior history on the bike. I have done a lot of work on it and am basically happy with the way it is. The one thing I haven't messed with is the Isolastics.

Is it possible to install new Iso's with the engine/transmission in the frame? It looks like I might be able to install new front Iso's with the engine in the frame. The rear, I am not so sure about.

Anyone done this?

rear-isolastics-t16887.html.

Not sure if it's the same with MK3.

Goggle < install isolastics on bike > might find text with pictures. Not sure about LH shift models but basically remove enough off engine to allow front to tip up to access from above the frame tabs. Rear is exposed by lifting frame to drop iso below Z-plate. Was a good review last few weeks here so just got down the subject lines or learn as ya go like some us won't to do.

why not just set them for starters .
Down Tight so theyre stuck ; thena gnats loose , so a timber lever shuffles cradle up & down . You just need clearance , nota lot . 2 thou its near free to Isolaterise . :mrgreen:
If its nasty then , youd look at rerubbering .

Now Matt how's a newbie to be initiated inot the Commando worshiping ritual of special words and blood letting? Its a nasty mean job to me but some find it just ordinary task. Much easier to share with a comrade. Here's the recent success story which i wish I had such photo hand holding first time. Commandos hurt so good some of us get more that one, so we can do it right the first time on at least one of em. Ya half way there once getting to point to just shim anyway and think of the next fella thanking you but missing out on really owning the dang thing. The cushions can decay in a number of ways, hardened to softens but all usually out of round sagging with age. Matt just flips his over I'm sure and re shims every few seasons.
rear-isolastics-t16887.html

[quote="calbigbird"Is it possible to install new Iso's with the engine/transmission in the frame? It looks like I might be able to install new front Iso's with the engine in the frame. The rear, I am not so sure about.

Anyone done this?[/quote]

As Matt suggests, adjust the front and rear isolastics first. Bike needs to be on it's wheels to do this. To check front iso. clearance lever the engine timing side away from the bottom frame rail and check clearance with a feeler gauge. Recommended is 0.006". Loosen isolastic mounting bolt and adjust as required. Rear iso you need to push the rear wheel from the drive side away from the frame. I use a foot on the wheel, with one hand on the seat/mudguard frame tubing. Check for clearance of 0.006". Torque iso. mounting bolts to 30lbft. You may find clearance is not equal all the way around the iso thrust face. If this is the case adjust at the point of smallest clearance. This is due to Norton production and assembly methods and not much you can do without complete strip down and necessary alignment. Well worth reading http://www.vintagenet.us/phantom/wsc.html. Or my website http://www.parallelengineering.co.uk. I can't recommend this work highly enough.

A common misunderstanding is that the rubbers affect the handling of the bike. They don't wear but can deteriorate over time. The job of the rubbers is to absorb the engine vibrations and isolate rider and a large part of the motorcycle. The handling is dependent, amongst several other factors, on the clearance between the isolastic thrust faces. Too much clearance and excessive movement between the rear wheel and steering head will adversely affect steering and handling.

You can remove the complete front iso assembly from the bike with out too much trouble. On a Mk3 if the rear iso rubbers need replacing then it is strip primary drive, remove gearbox and engine, remove rear wheel etc and then you can remove the engine cradle with swing arm. Swing arm bushes and spindle are normally worn out due to the oil having leaked out and been replaced with rain water.