Air box inlet rubber ring?

[Chris07]

I have a quick question. I have a K&N filter on my 02 600 (previous owner installed) Today I was cleaning the filter and I noticed that there is a tapered rubber ring in the inlet hole. I am not sure if this is part of the OEM cover assembly because I can’t find it on the parts diagram. What is its purpose? Would it be Ok to leave it out? It seems that it increases the air box inlet size a bunch if I leave it out.

[BarMatt80]

i take it that you don't have the pods, but a K&N stock replacement inside the airbox. The piece you are referring to is called a donut. when purchasing that k&n filter for the bike it comes with a large and small donut. You use either one based on your setup. Yeah if you take it out, it will flow more air.....try it it will run like crap...so put it back in.

[Chuckwick357]

BarMatt80 is right put it back in! Leaving it out will lean out your mixture and could do harm to your engine.

[Chris07]

I figured it would lean it out. When I purchased the bike it had a full yoshi exhaust with Dyna jet kit installed. From my understanding it was dyno tuned, so I would say it was probably tuned with the donut in.

Just curious why did the K&N kit offer two donets?

[Chuckwick357]

To adjust the airflow.
Sounds like you have the larger of the two installed. The smaller is for a stock setting the larger is used with aftermarket parts and some tweaking on the carbs. More air/fuel in, more air out, more power made.

[Chris07]

Here is a pic, I honestly think its the small one. You think its the large?

[Chuckwick357]

yeah that is the large one. The small one it 1/2 the diameter of that.

[Chris07]

good deal. Bike runs great. The only complaint I have is I have a slight popping when decelerating from 7K+ RPMs. Will bringing out the air screws a little help this?

[KatanaJim]

I can vouch for the air opening being very important. I just went from a UNI to the stock filter, and it runs 100% better now.