Mark3 top mount spring

MikeG

VIP MEMBER
Joined
May 31, 2012
Messages
1,350
Country flag
I'm installing a new Mk3 top engine mount. I recall from somewhere about an initial tension on the spring and adjust to suit from there. Tension was gauged by gap between the spring coils?
 
Last edited:
I did mine by loosening the bottom front iso through-bolt, then tightening the top spring until I could slide or tap the through-bolt back-and-forth easily
Works out, for my 850, to be about 43kg force, as described here - https://www.accessnorton.com/Norton...estions-for-a-72-interstate.32264/post-518059
Exactly so. That is the best course of MkIII spring adjustment, well proven. Keeps the front iso rubbers from sacking out, as they are prone to wear first of all (if the top two buffers don't split apart first)
 
My mk3 suspensory spring saddle has two positions to place the spring, changing tge angle to the engine trunnion. Is there advice on which position to use?
 
I used the one closest to the front of the bike, only way to get enough tension on the spring without bottoming out on the trunion
 
Rob,

When you do this adjustment, do you loosen the head steady or is that not necessary?
Thanks,Mike
Sorry Mike - didn't see your post.
I have the cNw, Dave Taylor type (two big rose joints) so loosening is not required.
Cheers
 
My mk3 suspensory spring saddle has two positions to place the spring, changing tge angle to the engine trunnion. Is there advice on which position to use?
I have tried both positions - the front one seems to give the "easiest slide" of the iso through-bolt, so I settled with that.
Cheers
 
Ride report....with the spring installed I immediately noticed the engine doesn't bounce around at idle like it used to, now the front wheel does just like my BSA or Triumph. Handle bars have no vibes at all and a mild buzz in the pegs at times. Mostly I notice the shake on deceleration that used to happen around 2500 RPM is gone. I removed the DT head steady and put stock back on cause the rose joints wore out too quick and I can't notice any real difference in handling either. Maybe Norton engineers had a clue after all?🤔
 
Rose joints lasted a year or so then got sloppy despite lubing them. If I was to ever change to something different again it would be the CNW mount. Looks a lot more robust and easier to set up.
 
You need seals for the rose joints for them to last.

Mark3 top mount spring
 
do you have a link for these bits? I'll be visiting the UK next month, so would be a Good Time
The are a fairly common item, you need to get the sizes you want sorted first and then search for them. Car tuning outfits seem to carry them in stock a lot.

Other option is a boot to cover it all.

Mark3 top mount spring


 
Rose joints lasted a year or so then got sloppy despite lubing them. If I was to ever change to something different again it would be the CNW mount. Looks a lot more robust and easier to set up.
Rose joints lasted a year or so then got sloppy despite lubing them. If I was to ever change to something different again it would be the CNW mount. Looks a lot more robust and easier to set up.
Mike,
Go to McMasters-Carr for the seals,rose joints, etc that you need.
 
Not sure if I'll ever go back to the DT steady. I really don't notice any real difference in handling (guess I don't push it hard enough?) And the stock setup is easier to get right, no fussing about with the bracket on the frame tube to get the rose joint rod aligned perfectly.
 
Back
Top