Isolastics

Hi guy's, just got my 72 Commando 750 and its got bad vibes so checked front mounts about 20thou clearance tookout shim pack just 1 shim of 20 thou is that normal or should there be more shims and is it worth converting to the later vernier type for ease of maintenance,just getting to grips with a few jobs.

Yes , the vernier isos are worth doing ... many years since I did mine , others will chime in best supplier , brand ... once setup you will be glad you did
Craig

With the shims, there is typically a stack. So you might add ten or twelve thou and try it. Your vibes might be more from the rubber in the isos than the gap at end cap.

The adjustable mounts are the way to go. 40 year old isolastics are most likely shot.

Quite likely the internal rubber buffers are sacked, worn, cracking, or even totally perished.

Check ebay for "racingnorton". Carl is a long-time supplier and has raced with these high quality stainless adjustables for years. They DO NOT require modifying / cutting down the front mount tube. Best price you will find, and great service. He also sells ALL Andover Norton parts, and has a very good inventory.

Please tell him I referred you to him.

Depending on how far you're inclined to strip the bike, it can be a bit of a hassle installing the vernier isolastic setups, but they're a must! IMHO … As is red rubber grease when installing new rubbers, which is part of the job – I only emphasise that because I'd never heard of it until I came to do mine, around 17 years ago. My experience is you don't need any special tools to fit them, even getting new rubbers in is pretty easy if you clean the tubes out thoroughly and are generous with the red grease; but my preference is for the type that's adjusted using a peg in holes in the circumference of the collar, per the MK3: I found the type with allen-headed grub screws much too fiddly. (sorry Mick!) Once fitted, adjusting the isolastics is a breeze. The only snag in my experience is that the rubber boots over the collars will perish in a few years, but you'd have that problem anyway! And consider a 'Norvil' or 'Dave Taylor' type head steady too, they are two very different setups but both complete the isolastic triangle and are so much more than just a go-faster add-on.

There are threads on how to do this job, here's one I found but there are others: http://www.accessnorton.com/NortonCommando/rear-isolastic-help.19133/

Thanks for the replies,will be going down the vernier route methinks need to sort it so I can RIDE her.