Will an XS1100 Airbox fit an XJ1100

[davidsymons53]

Will an XS1100 airbox fit an XJ1100?

[Yahman]

Not that I'm aware of, there are too many differences between the frames.

Larry

[DGXSER]

All I know for sure is that the XJ folks say their air box makes pulling carbs a PITA Plus compared to the XS1100.

[Jerry]

As a bolt-on mod, no. From memory, the XJ carbs use a 34 vs 32 mm inlet bell. You might be able to use the XJ inlet boots on the XS air box, but you might have to enlarge the box holes to fit; I don't know if diameter on the air box side is the same between the 2 models. The XJ mounts a bit differently in the frame, again you might be able to fabricate something but it would not be a bolt-in swap.

If you are looking to do this to get the advantages of a K&N filter, an old thread sows how to use the XJ filter frame to mount a K&N filter element to it. This would replace the dealer-only (and expensive) XJ filter.

From a post by Maximman:

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

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.

If you go to individual pod filters, make sure you get the 34 mm ones. Many parts houses get this wrong and list all XS / XJ 1100 carbs as the same size, 32 mm. Even the K&N website has it wrong, showing the XJ uses the same filter as the XS.

[trbig]

The carbs are listed as a 32mm carb which is the inside of the carb, not the bell. The bell inlet is 54mm on all the Mikuni 32 carbs. It was once believed on here that earlier carbs had 52mm and the XJ had 54mm... but in fact they are all the same if ordering pod filters.


Tod

[Jerry]

Thanks for the correction.

[nightpilot]

I might have an extra xj airbox. Not sure if it is complete but if you are interested I may be willing to get rid of it for a reasonable price. it is light and small so I dont think shipping would be much. If you are interested, let me know. I am now using a foam piece for the air filter in mine but am going to look into the K and N referenced above. I dont know what either would do to air flow and know proper air flow is pretty important with these things.