1975 Norton 850 Restore

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MS850 said:
L.A.B. said:
MS850 said:
Also seems to vibrate more than what i remember on my '70 Commando. It smooths nicely above 4K, between 2.5K-4K get tingling at the grips.
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Try backing off the Isolastics by 1-2 holes, and also slacken the head steady suspension spring nut by a couple of turns?

Edit: I don't remember you mentioning whether you changed the Iso. rubbers or not-so it could be they are in need of replacement if increasing the clearance doesn't reduce the vibration?
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Yes I did replace both Iso's, Im not sure they are adjusted correctly. I have clearance .008 on the side with the adjustment but none on the opposite side.
thanks
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L.A.B. said:
None of the info relating to the MkIII type kits seems to specify setting the clearance with a feeler gauge, but if you wish to do so then I suppose using a version of the earlier adjustment procedure will do.

I would try this:
First, the weight of the bike should be supported by the lower frame rails using a jack, blocks of wood or similar, so that the main stand is not touching the floor if it is a later model that has the main stand fitted to the cradle.

Checking front Iso. unit:

Slacken the central Isolastic bolt locking nut, pull the inner part if the L/H Iso. gaiter away from the Iso unit, lever the engine towards the right side and hold it there.
Then insert the feelers to measure between parts [23] and [24] on the left hand side (as shown on the parts book drawing link below)

http://www.bsa-regal.co.uk/norton/parts ... &Plate=015

The front Iso adjuster should be on the right hand side of the front Isolastic unit.

Check/adjust Iso. clearance then re-tighten the Isolastic bolt/nut.

Check rear Iso.

Slacken either Iso. stud nut. Push the rear wheel to the left and hold it there whilst checking, use the same procedure as for the front Iso. but this time check clearance on the right-hand side, the adjuster being on the left side of the rear Iso.

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Update

Backing off the *original* MkIII Iso. unit adjusters by a fifth of a turn sets the correct clearance, however the *conversion kit* adjuster setting could be different?
The Norvil recommendation for their own kit is back off the adjuster by half a turn. http://www.norvilmotorcycle.co.uk/techtalk04.htm
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LAB I found your info on adjusting the ISO, ill try this first
 
Well I got the ISO adjust much closer, a lot less vibration, basically I got in range according to adjustment procedures, then tweaked it a little. Ill leave it where its at for awhile and see how its goes.
I also installed a Atlantic Green Dyno Dave starter. Very nice, spins very fast.
I have a GoPro video riding the bike yesterday that Ill post.

Not sure if its easy to be done but it would be nice to have a continuing topic on both i.e. "Dash Cam" and "Lets see your bike on the road".
The SOHC4 forum has one with great success. Just a thought

http://forums.sohc4.net/index.php/topic,45183.0.html
http://forums.sohc4.net/index.php/topic,116660.675.html
 
I did a head re-torque, the speedo cable broke but I guess I rode about 150mi. I was surprised the bolts were as loose as they were. I also did a valve adjust, I checked the clearance before and after the re-torque, they were .009ex and .007in.
 
New foam and upholstery

1975 Norton 850 Restore

1975 Norton 850 Restore

1975 Norton 850 Restore
 
Keep that seat away from sunshine. Park in shade . Or indoors if possible. People worry about rain but it's sun. Pleats fail faster than unstitched too. So take care of it. No fat chicks. :)
 
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