Commando 961 Air filter

Hi,

Over the last few months I've been opening up my air-box to try and improve the airflow into the engine.

For this modification I need to cut a large diameter hole into the flat end of the filter, however my initial try wrecked the filter as the rubber doesn't cut cleanly. To overcome this I've made a tool (large tube with a sharpened edge) to punch the hole through.

Anyway... I ordered a new filter from Olivia in the Norton service department (very jolly & helpful). She informed me that the old rubber air filter was being discontinued, to be replaced with a new metal bodied one. This metal filter would be more difficult to adapt but luckily they had a few old ones left which she could send.

However, when the new filter arrived is only 75mm long not 100mm, which is unfortunately both more restrictive and doesn't match the modification I've made! Also from the photo I've seen the new metal filter appears to be shorter and therefore more restrictive!

I'm just about to return the filter back to Norton but was wondering if anyone on the forum knows what the origin is of the old filter as it's unlikely to be a bespoke Norton item?

Regards
Roger

What type of airbox alterations are you planning?

I don't know the origin either. But I did ask if K&N would make a filter to fit our bike and they (K&N) said no. I offered to send in the Norton Filter for copy but no was the answer. Not enough to justify making it. Can you send in a photo of the new filter ? Maybe the material is less restrictive ? Have you considered cutting a rectangular hole in the air box and fitting a K&N Panel filter ? If you put it at the front or rear of the air box it would appear unmodified from the side view. You would of course leave the stock filter in as well . At the front of the air box it would get lots of clean fresh air . Once you cut the rectangular hole you may need to divert the breather spigot a bit , but I personally wouldn't worry about that because so little oil comes out now since the update .

Hi,

I struggled to load the pictures onto the forum however, I have also put a post on the Norton Commando 961 Facebook page... hopefully the mods will clear when you see them. The new aperture is on the underside of the air-box (same as the Dominator) as this doesn't get splashed by spray from the rear wheel. With the inlet funnel sprayed black it's virtually invisible.

Looking at the material and construction of the new air filter it appears to be identical, other than having only 75% of the surface area!

I cant find the facebook page . Do you mean you have two OEM filers installed in the airbox ? One in the stock location and another coming in from the bottom ? I didn't realize there was enough room in the box for that. I thought that the filters would hit each other and not fit. But if it came in from the front it may clear ? I think the panel filter would allow an open clean shot onto the throttle bodies in my view. But I am interested in seeing your project !

Me too.

If you loom for the Norton Commando 961 group on Facebook hopefully you can see the photos.

With regards to the filter, I'm not stacking two filters, I'm just using the stock filter (old type) but opening up the bottom to allow me to add an additional air feed from the underside of the air-box. If the new factory air filters are shorter, they unfortunately wont be long enough to reach my new opening. I've been looking at the K&N site and there are a couple of likely candidates there however they don't have the wide diameter top to mate with the existing air box end. I might therefore buy a K&N and fit it with the entry hole facing down to connect with my new hole as it is a lot less restrictive than the under seat position.

Sounds like you're designing something like the bottom air feed that the Dominator airbox has to augment the normal top feed of the Commando airbox.

Yes, the modification is similar to the Dominator, however I should also have a top feed as well.

Cool!
Any photos yet?