isolastics

It's worth it if you do a lot of miles or want to play around with clearances for best handling/min vibration etc. I have the Norvil front and back and while they are OK ignore the 1/2 turn instructions or you'll have the sloppiest Commando out there. Also the non adjustable end is a very loose fit on the through bolt (guess they found the nearest stock metric tube!).I only noticed this recently and shimmed the front with a piece of old feeler guage wrapped into a circle. Ideally it should run the whole length of the tube but we'll see how it survives. Haven't done the rear since that's major work. The alternative is the Mick Hemmings set-up which uses existing Isos and adjustable end caps.

Just a note to say that I installed the Mick Hemmings system last year and it seems to work very well. The old type shim system will last only for a finite amount of time - but then you have a problem!

Just to confirm Peter's note, I have installed three Hemmings conversions are they are trouble free and simple to fit. To make the most of any isolastic set up you must follow the instructions to the letter.Therefore not have anytension on the engine cradle which means using a frame lifter to get the rear wheel just clear of the ground. I recently bought such a device at a show, and it is basically a scissor jack between two flat plates with adjustable forks which can slide across to fit any lower frame rails. Its a mini version of a chassis lift in a car workshop.

Speak to Angela Hemmings, she'll sort you out !!

Previously wrote:

Hello,

i've gone to website technical area. I dont see a section for isolastic. I have the older style iso's and dont know if i should change to the MK3 vernier adjustable type. I have two drive units on the bench so the upgrade is easy at this point, if warranted. i'd like to read some technical on it (pro's and con's). Is it here somewhere that i've missed?

Hi,

Google 'worlds straightest commando'. An excellent article providing plenty of sound advice on setting up isolastics and more.Not surprised by the sloppy parts from norvil.

Good luck, Simon.

Previously wrote:

Previously wrote:

Google 'worlds straightest commando'. An excellent article providing plenty of sound advice on setting up isolastics and more.Not surprised by the sloppy parts from norvil.

Good luck, Simon.

Yes - a great read. Did as much as I could but without redrilling the mounts. Mine had a blowup in 02and bent the LH frame railforward by 7mm. In addition to fixing that the article helped me find my front and rear ISOs had different offsets (0.25" rear and 0.31" front) and had to square them up and machine 060" off theRH and add washer to the LH. It cured the 75+ weave I'd always had. made sense really since the whole drive and wheel assy had been pointing left.

Speaking of Isolastics. I have just fitted new adjustable isolastics from Mr Hemmings, the question is, on the rear, should the spindle that holds the isolastics to the frame, be a tight fit. I fitted the engine cradle into the frame yesterday and placed the spindle through to secure, but it is a sloppy fit and there is some movement on the shaft - is this normal?

Thanks

Jamie

Probably, that was the issue on the non adjustable side with my Norvil parts. Not seen the MH items in the flesh but on Norvil items the clearance is set by the tube on the fixed side and on the adjuster by the adjuster diameter which is a better fit. I shimmed the front but have not touched the rear which is likely the same issue. It probably does not make too much difference because if you have the same slop front and rear and since the sloppy sides may be diagonally opposite (adjusters are diagonally opposite) it could even out. What I've done is fix one end and I should do the rear. If yours have the same slop side to side it is probably OK.

Ok maybe it wasn't well explained. On the Norvil Mk3 vernier conversion for non Mk3's the tube with molded rubbers and buffers is at least 025" larger bore than the bolt (I used an old 012" feeler cut to length and inserted inside thefixed end (360 deg) and still had clearance). The fixed end is a larger diameter than the adjustable end whichhas atighter ID for a good fit over the bolt. I'm guessing but I'd assume the actual Mk3 replacements have the same tube size as the conversion. Hope that helps.