1975 Norton Mk3 distinguishing features

L.A.B.

VIP MEMBER
Joined
Nov 20, 2004
Messages
15,455
Country flag
no data at all in this manual for dimensions other than Section F with bushing dimensions.

pdf page 8:




The section F bush dimensions aren't correct. The Mk3 shock lower bush is Edit: 0.942" wide.
 
Last edited:
Joined
May 28, 2003
Messages
1,977
Country flag
The little bit of crap/grit that tries to pass by the piston, on it's way to the exit hole marked in red, will also dig into the aluminum and score it a bit.
Cleaning and buffing off/crocus cloth the piston is good... but unless you also remove the aluminum scratches you will never restore a slick surface and it never works as well as it should. It is a bit of an inspection and maintenance item if you want it to work reliably.
 

p400

VIP MEMBER
Joined
Jul 14, 2014
Messages
1,043
Country flag
Were the front and rear brake rotors chrome plated when original?

FrontRotorChrome.jpg
 
Last edited:

Jerry Doe

Admin
Joined
May 21, 2003
Messages
1,489
Country flag
The crank cases are stronger on a mk3 around where the main bearings go in
 

p400

VIP MEMBER
Joined
Jul 14, 2014
Messages
1,043
Country flag
What supplier sells the best stock exhaust system for a MK3?
Pipes, mufflers, crossover, clamps , gaskets, flange nuts, etc.

Not looking for performance upgrade, not looking for more sound.......looking for quality components.

if it is a common manufacturer/supplier, looking for best price from vendor.

Advice welcome .
Thank you


1975MklllInterstate.jpg
 

L.A.B.

VIP MEMBER
Joined
Nov 20, 2004
Messages
15,455
Country flag
Original 'black cap"/"bean can' silencers/mufflers or (more popular) 'peashooters'?

Peashooters use a different set of mounting plates.
 
Joined
Mar 30, 2012
Messages
612
Country flag
View attachment 8836

Part 36 circlip on the rear shocks diagram; for the Mark 3 rear wheel change the brake caliper bracket needs to be loosened for removal by loosening the lower right shock bolt nut. The circlip would help to limit backing off the nut.

Removing and re-installing the Mark 3 rear wheel is almost a 2-man job.
 

p400

VIP MEMBER
Joined
Jul 14, 2014
Messages
1,043
Country flag
Original 'black cap"/"bean can' silencers/mufflers or (more popular) 'peashooters'?

Peashooters use a different set of mounting plates.
black cap bean can seems the best, but it would be nice to know who sells the best of either.
Thank you
 
Joined
Dec 22, 2006
Messages
5,018
Country flag
If replacement Black Caps are the same as the originals then these will give you a very quiet bike with a power-sapped top end.

Glen
 
Top