Isolastics

Greetings All!

Am getting ready to dig into my rear isolastic for the first time. Knew the day would come as I have no idea how hold the current set up is.

Doing a bit of research and thought I would poll the collective minds of the forum for info.

Old Britts has the MKIII conversion available for a fairly reasonable cost. As Daisy is a MKII this would be considered an upgrade.

My questions are; is it worth going to the MKIII? Can the job be done without removing the engine?

Tips are much appreciated!

Thanks...

Hi Dave,

The rear is the hard one. If you put several thousand miles a year on your Commando, it might be worthwhile converting to the vernier Mk3 adjuster. You don't need to remove the engine to adjust the shim type you have. I use a floor jack under the engine cradle, remove the stud going through the rear mount then raise the whole cradle by jacking it up.
It's a tight area, but you can get the rubber gaitor pulled back enough to insert a blade type feeler guage between the end caps and the PTFE washer. I check on the left side while using a bar to pry the cradle to the right side as far as it will go. Once you determine the gap, reduce this by adding shims even to each side until you have a .010" gap. Don't go too tight or you'll get a lot of vibration or even a cracked frame.

The front mount is easy. Just remove the whole thing remove the rubber gaitors, put the bolt back through, tighten then measure the gap. Again .010" is advised. The Mk3 vernier will not go into the pre Mk3 until the cannister is machined. The vernier type sold by Norvil Motorcycles that will go into the cannister is more difficult to adjust, less room.

Just ordered iso kit from Phil Radford of Fair Spares America, San Jose for $115 each front and rear. New style does not required any modification of front mount, rears are the same, no modification required. These units are of the better MK III type, not stock ones.
Dennis
Vancouver, Washington

Hi Denny850,

Keep us in the loop. I want to know how the conversion/installation goes for you.

I just met Phil last weekend at the NCNOC ride.

Received new type MK III isolastic's (no modifications required on my 1971) from Fair Spares America. They are very nice and machine work is first class. I have removed my engine and tranny and then the complete bracket w/swing arm. Phil Radford told me old isolastics will come out without much difficulty. I removed the front iso housing, taped it up (new paint) and put in my vise with heavy towel protection and took a large, long socket the size of the inner diameter of housing and proceded to hammer it out. Didn't take much to get it out. I then took a round file and wrapped it in sand paper and cleaned up the inside bore. I then took (per Phil's recommendation) a little bit of brake grease (use only BRAKE grease, not axle/bearing type, etc. grease which will harm rubber) to lube the new rubber to ease it in. Installation only took hard hand pressure to go in. Used same procedure on rear. They look great and I can hardly wait to get bike back together to adjust and see the difference. I also bought the new headsteady that Old Brits has made up, man is it sweet. My rear swing arm has zero play and appears to be in great condition so will not mess with it. Of course this is the time to do a rebuild when it is out of the bike and access is easy. Will keep you posted.

Hi Denny,

Nice detailed report. I'll need your notes later I'm sure.

FYI ... I use DOW Corning Silicone grease (white/blue tube) when I need to lube rubber parts. It's very slick, doesn't attack the rubber (inert), and lasts for an eternity. I use it on many of my o-rings and seals. I put the thinest film I need. (Don't use it for the caliper piston seals though ... any excess can find its way into the small orifices). The tube I have is older than my Norton :lol: