View Full Version : Atc250r k&n filter support rings made easy

10-27-2010, 08:42 PM
I was sitting there looking at my K&N filter, a bare airbox with my digital calipers and i happened to glance over and notice that a Coleman 16 OZ propane tank looks like a match.

Guess what.... it is! ID of plastic air box hole is 25~30 thou (.025inch) less than OD of 16.4 oz Coleman green propane tank. Its the Coleman propane tank with a black plastic bottom glued on. There are different makes and models of these tanks so measure.

I left the propane open all night on a just about empty one. cked it 3-4 times. And in the morning I clamped tank in vise SECURELY and carefully drilled a 3/16 hole facing away from me! No problem. Measured out, using Dykem layout or you can use some hose clamps, scribed 1.500in wide rings (2) 1 ea for both my trykes, on side of tank away from stamping grooves etc. Used thin blade cutoff saw and whala DONE. Deburred edges on belt sander and sanding drums and pressed in 1/4 inch by hand with gloves on and cloth. Very Hard to press in!. Used a propane torch to "heat" the rest of the airbox a "little soft". And then quickly pressed the sleeve home.

Sorry DC but I am always tryin' to save a buck and make a functional product. $3 buck for 2 (+) ? rings. And you get to use the propane first. When you clamp K&N in place it it feels very solid. And it helps support the other side where intake boot to carb clamps on. Have at it!!


10-27-2010, 08:46 PM
nice idea!!

10-27-2010, 08:59 PM
Trust me, I learned back when I got layed off that 3WW wasn't gonna contribute to my income very much. Be my guest to buy propane tanks, empty them and do that work to get them cut and square.

BTW, I tried 3 250R air-boxes, ALL were about 1MM smaller in the center, I guess from tightening and loosening the clamps........ I'd make a sleeve and it would be tight in the center but not so great on the boot and AF; Then again, I'm fussy and I like aluminum......

I found 2 slightly larger rings to fit better but no one will cough up the cash or I'd be making them. If I get firm requests, I'll make them.....

Billy Golightly
10-27-2010, 09:15 PM

11-07-2010, 10:42 PM
Not made easy but............

These are a couple shots of the aluminum rings I make for the 250R.

Out of the airboxes I had, a single sleeve didn't fit or I had to make it a bit smaller and then they didn't support the plastic.

There are deviations from one airbox to another for whatever reasons.

09-23-2011, 11:28 AM
Great idea!! Will be doing this little project this weekend!!