Unofficial Royal Enfield Community Forum

Royal Enfield Motorcycles => Bullet with the UCE engine => Topic started by: avandr on October 01, 2012, 07:35:57 am

Title: Air Box / Filter
Post by: avandr on October 01, 2012, 07:35:57 am
Opened my airbox today to install K&N filter, I was surprised to see a moulded plastic cover sealing the inlet and outlet. Manual did not show this. I am just wondering has anyone attempted sealing the box and discarding this plastic cover? It is a pain trying to centralise the airfilter with this arrangement and I am sure the EFI would breathe a lot better without this.
Thanks in anticipation
Title: Re: Air Box / Filter
Post by: Kevin Mahoney on October 01, 2012, 07:48:08 am
It was added to keep debris (such as the c-clips on the locks from entering the engine. Remove at your own risk. The risk is slight but it is a risk. Don't do it during warranty
Title: Re: Air Box / Filter
Post by: FiRE Comms on October 01, 2012, 08:01:51 am
remember also that the filter works backwards to normal thinking...  dirty air entering the air box from the center of the filter, clean air in the plastic molding going to the engine...
Title: Re: Air Box / Filter
Post by: JVS on October 01, 2012, 10:22:32 am
Sorry about the mini hijack but I also had a quick question regarding the K&N filter.

I get about 32 kilometres per litre or 75 US MPG with the stock air filter even though I ride a bit aggressively sometimes. Should I consider the K&N filter for higher MPG-Km/L, or it will negatively affect the mileage? Thanks
Title: Re: Air Box / Filter
Post by: gremlin on October 01, 2012, 01:59:38 pm
It is my belief that the stock configuration is your best choice for economy.  Any of the "easier breathing" enhancements will require more fuel.
Title: Re: Air Box / Filter
Post by: barenekd on October 01, 2012, 06:00:40 pm
If there was any mileage change between my K&N and the stock filter, it couldn't have been more than 1 mpg.
Do not remove the plastic cover, you will have no filtration! As mentioned, the filter works from the middle out. Common misconception on this filter box.
Bare
Title: Re: Air Box / Filter
Post by: Bulletman on October 01, 2012, 06:59:00 pm
Opened my airbox today to install K&N filter, I was surprised to see a moulded plastic cover sealing the inlet and outlet. Manual did not show this. I am just wondering has anyone attempted sealing the box and discarding this plastic cover? It is a pain trying to centralise the airfilter with this arrangement and I am sure the EFI would breathe a lot better without this.
Thanks in anticipation
Avandr, It looks difficult but its fairly easy to do. I have a C5 and just installed the K&N about 10 days ago. I kept the plastic cover as is. But I did 2 things which made my life easier. 1. Using Monster glue I glued the Round black Metal plate to the Filter, I'm sure any strong glue will work, Mine took about 45 minutes to dry out in the Mildly hot California Sun.  2. I unscrewed the nut at the bottom of the filter housing which helped me insert the filter inside a bit more easily. then I re-tightened the same.
Title: Re: Air Box / Filter
Post by: eda1bulletc5 on October 01, 2012, 07:47:55 pm
Hi Folks,
Which plastic cover on the K&N filter are we mentioning about.

I have the filter (just the filter no plastic covers any where on it) to the air filter box with the OEM black plate that goes on top of the filter and bolted to the housing. I did make sure that there are no gaps between the plate and filter.

In the air box itself, there is the plastic molding on the edges of the air box (black in color) that sought of seals the airbox when it is closed. I dont think we are talking about those - as they have no connection to K&N filter.

Thanks.
Sajiv
Title: Re: Air Box / Filter
Post by: barenekd on October 01, 2012, 08:11:45 pm
He was talking about the airbox top.
Title: Re: Air Box / Filter
Post by: Ducati Scotty on October 01, 2012, 08:12:02 pm
The C5 has a black plastic cover that nestles inside the metal triangle box over the filter.  The original bikes just had the metal triangle box but the seal on the edge was less than perfect, the hinges were an obvious leak point, and the small springs on the hinge could break and get sucked into the intake.  The plastic insert solves these problems.  It was retrofitted to the older bikes free of charge and is now standard equipment on the newer ones.

The G5 and B5 does not have the same airbox and do not have these problems.

Scott
Title: Re: Air Box / Filter
Post by: gremlin on October 01, 2012, 09:38:00 pm

The G5 and B5 do not have the same airbox and do not have these problems.


My 2011 B5 has the same triangular tool-box looking air filter on the starboard side.  within it is a plastic cover that forms the intake plenum around the air filter.

there is just enough room left inside the box for my registration and insurance papers (inside a zip-loc bag).

Title: Re: Air Box / Filter
Post by: eda1bulletc5 on October 01, 2012, 09:47:53 pm
ok... is this the cover?

http://www.google.com/imgres?start=74&hl=en&biw=1920&bih=1115&tbm=isch&tbnid=GOYUwKaQupMRJM:&imgrefurl=http://www.bcmtouring.com/forum/motorcycles-f13/my-new-royal-enfield-classic-500-efi-t17139-305/&docid=ncyo0uXOznkfqM&imgurl=http://www.bcmtouring.com/forum/attachments/airfilter.jpg-149639d1299752695&w=1024&h=613&ei=ogBqUOrgCc_2iQKutoHQCg&zoom=1&iact=hc&vpx=465&vpy=732&dur=3233&hovh=174&hovw=290&tx=123&ty=201&sig=105799333652208207213&page=2&tbnh=96&tbnw=161&ndsp=83&ved=1t:429,r:54,s:74,i:174 (http://www.google.com/imgres?start=74&hl=en&biw=1920&bih=1115&tbm=isch&tbnid=GOYUwKaQupMRJM:&imgrefurl=http://www.bcmtouring.com/forum/motorcycles-f13/my-new-royal-enfield-classic-500-efi-t17139-305/&docid=ncyo0uXOznkfqM&imgurl=http://www.bcmtouring.com/forum/attachments/airfilter.jpg-149639d1299752695&w=1024&h=613&ei=ogBqUOrgCc_2iQKutoHQCg&zoom=1&iact=hc&vpx=465&vpy=732&dur=3233&hovh=174&hovw=290&tx=123&ty=201&sig=105799333652208207213&page=2&tbnh=96&tbnw=161&ndsp=83&ved=1t:429,r:54,s:74,i:174)

If this is the one, I need to check with my dealer on this.

Thanks!
Title: Re: Air Box / Filter
Post by: Ducati Scotty on October 01, 2012, 09:52:17 pm
Thanks for the correction Gremlin.

Scott
Title: Re: Air Box / Filter
Post by: Arizoni on October 02, 2012, 12:17:37 am
eda1
The black plastic cover is the outer part of the inlet plenum.
If you remove the metal sidecover and you are looking at the air filter your motorcycle is missing an important  part.
If you remove the metal sidecover and your looking at a black plastic cover that is totally inclosing the factory air filter like I see in your link you don't have a problem.
Title: Re: Air Box / Filter
Post by: motorat on October 02, 2012, 12:23:53 am
yep that's it.
make sure your passenger peg is down or it won't open all the way.
Title: Re: Air Box / Filter
Post by: gremlin on October 02, 2012, 12:35:56 am
Thanks for the correction Gremlin.

picking nits = hobby
Title: Re: Air Box / Filter
Post by: JVS on October 02, 2012, 12:50:38 am
Thanks for the clarification, Bare and Gremlin  :D I shall stick with the stock filter.
Title: Re: Air Box / Filter
Post by: avandr on October 02, 2012, 01:20:32 am
Correct me if I am wrong guys, improving an engines breathing both in and out must give improved fuel economy? I believe where people are seeing reduced economy is due to the fact that there is a small increase in power and they tend to screw on the throttle a bit more.
Cheers
Title: Re: Air Box / Filter
Post by: Jack Leis on October 02, 2012, 01:24:30 am
Correct me if I am wrong guys, improving an engines breathing both in and out must give improved fuel economy? I believe where people are seeing reduced economy is due to the fact that there is a small increase in power and they tend to screw on the throttle a bit more.
Cheers
  True that !
Title: Re: Air Box / Filter
Post by: Arizoni on October 02, 2012, 01:30:31 am
I wouldn't expect to see any noticeable improvement in economy by changing the air filter to a K&E or some other type of free flow filter.
The greatest economy is had with minimal throttle settings where very little air is flowing thru the filter.  This being the case, the differences in air flow thru the filter would not be noticeable to the engine.
The only time this would not be true is if the air filter was plugged up with dirt (or in the case of the K&E, over oiling).

Of course, everyone who installs a free flowing filter wants to see more power so it is pretty natural for them to "dial it on".
Title: Re: Air Box / Filter
Post by: jartist on October 02, 2012, 01:44:59 am
My reason for switching to the K&N is that I have had issues with the airbox sucking in oil from the crankcase.  I know it's from overfilling the engine with oil but some bikes are more prone to oil over-fill symptoms than others and it's really easy to do.  If you get ANY oil on the stock paper filter it is contaminatied/clogged and will lower the pressure in the airbox and just suck more oil out of the engine.  I figure with the K&N it just gets a mist of more oil and if need be I can clean it and start over.
Title: Re: Air Box / Filter
Post by: Jack Leis on October 02, 2012, 02:30:03 am
Never had an issue with crankcase oil in my air box. I ran some 3/8" fuel hose from the crankcase vent connector and ran it up over the airbox to just above the right side top shock mount and tie wrapped it to the seat frame. Plugged the breather hole in the airbox with RTV sealer and that took care of the burping on the K&N. Got the idea from Bare about 12,000 miles ago. The crankcase breathes clean as a whistle.
Title: Re: Air Box / Filter
Post by: gremlin on October 02, 2012, 07:28:00 pm
the thermal efficiency of the engine does not improve with changes to the air-filter / exhaust    UNLESS  you modify the systems (and the cams) enough to radically alter the combustion ....... like ..... forced induction.

but then again, we are talking about the desire to make our machines special !  like us !!

Title: Re: Air Box / Filter
Post by: Fogrunner on October 03, 2012, 03:55:37 am
Special being the operative word!!