Air Filter

HFA4609

http://www.hiflofiltro.com/17.0.html?&L=0&sel_uid=1925

http://www.powersportsuperstore.com/HiF ... 057799.htm

Is this the correct air filter for a 1981 650 midnight maxim? I had some trouble starting it this morning. It was turning over when I had my finger on the starter and choke open. But once I removed my finger from the starter it died. I was thinking of everything I had done since I last started it. Oil, plugs, battery, air filter. It occurred to me that I hadn't started it since replacing the air filter. I put the old filthy one in and it started up.\

Is there something I need to do to prepare the new air filter? (oil it, and where etc). Maybe it wasn't installed snug enough? Is this the wrong filter since its called HIFLOFITRO?

Thanks.
Rob

 

Sure looks like the right one.
Your stock cotton gauze types do NOT require oiling, you will ruin them if you do. The aftermarket units (UNI, K&N, etc...) do require the oil.
If your starting problem went away with a dirty filter, your carbs are not clean. The dirty filter is blocked up, creating a richer mixture (less air) indicating your cold start enrichment circuit (or other circuit) is not working correctly. Given I am no carb guru, I'll leave the diagnosis to those more learned than myself.

 

Its running now with the new air filter. Maybe the bike had just been sitting too long and it was a coincidence that it started when I pu in the old filter.

 

Just for the record, I went to a K&N filter on my 85 XJ700N and the performance is much better.

 

I never understood why the filters get oiled.

 

Foam filters are oiled to remove dust, it gets stuck in the oil as the air flows through the passages in the open cell foam, and can offer a much lower overall resistance for the same filtering efficiency. My old TY250A trials bike had an oiled foam filter as stock, as do most dirt bikes. I have a Briggs and Stratton engine on the mower with a paper filter AND an oiled foam filter over the top, aye ... to be sure, to be sure ...

 

Its the right one.
Don't OIL it.

Getting it to fit required some "Fin-egg-ling"

The Foam Rubber SEAL on the open end is a little-bit thicker than Stock OEM.

A time saving trick is:

Place the Filter in the Box.
Use a 1-Inch wide strip of Duct Tape to anchor the Filter's "Ear" to the Top Edge of the Box.
Let the Tape hold the Filter as you position the Lid in Place.

Poke a hole in the Tape and run the Front Screw right through the tape.