A K&N Mod for an XJ

[MAXIMAN]

Everyone knows K&N made a filter for the XS air box. And...everyone knows they didn't make one for the XJ.

Well since I'm doing a complete performance upgrade to Zilla I had to figure out a way to install a K&N filter without going to pods. I don't want pods on Zilla because it's my road bike. Occasionally on one of those 3000 mile road trips I'll get caught out in the rain. Besides I don't particularly care for the look of indivdual filters.

This is a very simple modification. I took an OEM breather and cut the paper element out leaving the metal frame.

Then I used a K&N "drop in" panel style filter that was very close to the dimensions of the OEM filter frame. The K&N number is 33-2586. I ordered direct from the K&N website.

The width was exact. But the length was slightly long by about 1/4 to 3/8 inch. I cut it to length and used RTV to seal it in the frame. Then I used JB Weld to reassemble the frame cross-member to the frame.

In theory it should allow the engine to breath more readily...but I can't prove that. If I feel like it I do an A-B dyno run while the bike is locked down on the rack to see if there is any difference between the two. I'm not betting it will be discernable but ya never know.

Here's pics:

[GNEPIG]

.. i'm betting you will be able to tell the difference.

[MAXIMAN]

I hope you're right. It went to a lot of trouble to build that filter.

We'll see.

[DiverRay]

Maximan,
At least you only have to build it ONCE! After that, clean and go like the rest of us with the older filters.
Ray

[MAXIMAN]

Well Ray the problem is I'm like GNEPIG. I'm actually crazy enough to think I could improve upon my own design.

But I'll likely take your advice and quit right there.

[trbig]

I don't want pods on Zilla because it's my road bike. Occasionally on one of those 3000 mile road trips I'll get caught out in the rain.

I have heard this discussed on here a couple times, and I just don't see it. I can't see anything actually getting in to the pod filters besides a light mist... maybe if they faced forward... but they don't. Engines actually run better with moist air.... moisture turns to steam in the cylinder.. expanding and actually improves compression ratio a little. I could see an actual ingestion of straight water, but I just can't see how a little water could hurt through a pod filter. By the time it makes it's way through the filtering material, it would just be injested in a mist. I know I ran mine through the car wash the other day, high presure EVERYTHING... even the pods.... busted right off afterwards. I may try misting them with the hose with it running and see if it does anything.
Now that mine is up and running... I may just ride it in the rain! lol.

Tod

[andnew]

From my past life playing with 4x4's they run K&N specifically because it won't allow large amounts of water through the filter when properly oiled. Especially when fording when a large ingestion of water would cause engine damage.

My XJ lives outside with pods and we get plenty of rain here in the northwet. (In fact it's raining now). I've never had a problem with any water passing by the K&N's

[Dan Hodges]

Re: A K&N Mod for an XJ

Originally posted by MAXIMAN
Everyone knows K&N made a filter for the XS air box. And...everyone knows they didn't make one for the XJ.

Well since I'm doing a complete performance upgrade to Zilla I had to figure out a way to install a K&N filter without going to pods. I don't want pods on Zilla because it's my road bike. Occasionally on one of those 3000 mile road trips I'll get caught out in the rain. Besides I don't particularly care for the look of indivdual filters.

This is a very simple modification. I took an OEM breather and cut the paper element out leaving the metal frame.

Then I used a K&N "drop in" panel style filter that was very close to the dimensions of the OEM filter frame. The K&N number is 33-2586. I ordered direct from the K&N website.

The width was exact. But the length was slightly long by about 1/4 to 3/8 inch. I cut it to length and used RTV to seal it in the frame. Then I used JB Weld to reassemble the frame cross-member to the frame.

In theory it should allow the engine to breath more readily...but I can't prove that. If I feel like it I do an A-B dyno run while the bike is locked down on the rack to see if there is any difference between the two. I'm not betting it will be discernable but ya never know.

Here's pics:

I have never actually looked at the filter from an XJ before, but from these pictures it looks to have more surface area than the filter from an XS.I will be going to Yamaha to get both stock filters and compare them.A modified XJ air box on an XS 81 Special,interesting.

[MAXIMAN]

Originally posted by trbig


I have heard this discussed on here a couple times, and I just don't see it.

Tod

Sorry if you don't see it bro. I have a friend in Ponca City htat put pods on his ZRX. He got cought out in a down pour and claimed his bike would barely run after being in it for about 30 minutes.

I don't want to take any chances of being "dead in the water." pun intended

The last thing I want is to be somewhere between Delta, UT and Fallon, NV...in the middle of nowhere and have a problem in a rain storm. I may be paranoid but so be it.

Secondly I simply do not like the look of the individual pods. Just a preference thing. I actualy prefer the look of the stock air box.

Stay tuned for one of the coolest mods you'll ever see for a XJ11 in a new thread. hehehehe...