850 Air box fixing

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mdt-son

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Hi all,
A trivial question: Where in the spares book are the fixing screws for the Mk2A & Mk3 air box listed? I couldn't detect them anywhere.
In case NVT forgot to list them, can someone please state dimensions? There are two screws at the bottom which attaches the air box to the battery tray, and one at the top which connects the angled bracket to the front frame gusset plate.

- Knut
 
There is a 3/16” spacer between the air box top tab and frame gusset as well. Same as the ham can air box. You have to have excellent manual dexterity to assemble at this point :) Part number 24 in Andover’s list.
 
Yes, the same - including the spacer (was about to post when David posted first!).


'A' specific hardware here:
andover-norton.co.uk

Andover Norton Parts Drawings - Genuine Andover Norton Factory Parts - Commando Parts

Andover Norton Parts are the only Norton spare parts in the market manufactured to original drawings, within the factory-approved tolerances, from the correct materials, and with the correct finish.
andover-norton.co.uk
 
Great info, guys. I didn't know the ham can air box had identical fixing points.

- Knut
 
mdt-son said:
Hi all,
A trivial question: Where in the spares book are the fixing screws for the Mk2A & Mk3 air box listed? I couldn't detect them anywhere.
In case NVT forgot to list them, can someone please state dimensions? There are two screws at the bottom which attaches the air box to the battery tray, and one at the top which connects the angled bracket to the front frame gusset plate.

- Knut
Click to expand...

I did not use the standard length box to chassis fasteners as I found the fit of the airbox (Mk2A) could be improved with a new top spacer (brass) and a spacer plate (plastic) at the battery tray mount.

I had posted this thread long ago (with next to no interest) but like the plastic (still air) airbox but in modified form.
It would also be possible to pick up cooler air from under the bike via the space between the engine and gearbox.

A good design that was a step backwards on the later Mk3 with its riveted attachments that were bolt on with the Mk1A/Mk2A for easy installation when the box is installed upside down then rotated CCW.


Mk111 and A model air boxes including JPN.

These pictures seem to good to waste for those interested. Mk111 850 air box.
www.accessnorton.com www.accessnorton.com
 
Hello Time Warp,
Thanks for re-posting pictures in the other thread!

If your spacer is thicker than 3/16" (item 52 in the ham can spares fiche), it raises the air box a few mm and locates it slightly to the rear, so now the lower mounting holes may no longer fit the battery carrier.
I guess that's the reason why you fitted a spacer plate there. With all respect, how is this modification an improved fit? If the air box fitted poorly in the original position, wouldn't it be more sensible to modify the top bracket only, or fabricate a new bracket? Are you taking fit of left side cover into account? I may be missing some information here, so please fill me in.

As for the rear air entry, it's a nice peace of fabrication, but I am not sure what the purpose is. An opening for the engine to suck in unfiltered air? Those curved integral intakes provide the advantage of filtering out all droplet moisture, which the ham can air box can't do. Yes, the ability to allow cooler air in (vs. the previous air box design) is a distinct advantage too.

- Knut
 
Last edited:
mdt-son said:
Hello Time Warp,
Thanks for re-posting pictures in the other thread!

If your spacer is thicker than 3/16" (item 52 in the ham can spares fiche), it raises the air box a few mm and locates it slightly to the rear, so now the lower mounting holes may no longer fit the battery carrier.
I guess that's the reason why you fitted a spacer plate there. With all respect, how is this modification an improved fit? If the air box fitted poorly in the original position, wouldn't it be more sensible to modify the top bracket only, or fabricate a new bracket? Are you taking fit of left side cover into account? I may be missing some information here, so please fill me in.

As for the rear air entry, it's a nice peace of fabrication, but I am not sure what the purpose is. An opening for the engine to suck in unfiltered air? Those curved integral intakes provide the advantage of filtering out all droplet moisture, which the ham can air box can't do. Yes, the ability to allow cooler air in (vs. the previous air box design) is a distinct advantage too.

- Knut
Click to expand...

The inlet at the rear does have a filter but is not shown.
As far as the airbox it first got a spacer at the battery tray mount to move the snorkels forward slightly, so they had clearance to the battery tray.
The top was then adjusted so suit.

As far as the Mk1A/Mk2A left hand side cover that was the step backwards with the Mk3. (imho)
The Dzus fastener ( 06.4066) being on the battery tray lower sets the position of the cover, the other two brackets for the rubber grommets are bolt on so adjustable to some degree in stock form.
As posted, why they elected to use peel rivets on the MK3 is anyone's guess (drunk perhaps)

Because my preference is stock looking bikes, attention to detail comes into play as in nothing is to much trouble. (Not to be confused with pedantic or perfection)
#
As someone 65 yo this year I see firsthand what happens to old men in daily life, if you do not push yourself as you get older you will quickly become just that both physically and mentally.
I call it, waiting to die syndrome and many do not know they already have it.
 
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