Original foam vs K&N - '80 850L

[Guest]

Hey folks, I was working on my son's '80 850 GL last weekend and replaced the original (I think) gray foam air filter with a K&N filter that fits on the same screw-in platform. The main idea was to seal off any intake leaks, so we replaced foam strip that jams up against the intake.

The "original" foam filter is about 1/4 inch thick all around. With a K&N, the engine started up with a slight difference in choke settings, etc. but still ran fine as far as I can tell.

Do you you have an opinion on using the gray foam filter vs a K&N? I use a K&N on my bike and it works great, so I put one on my son's bike, but wondered if he should stay with the original foam filter.

[Nessism]

The Suzuki brand air filter foam is green if I'm not mistaken so not sure about that gray one of yours. Uni branded foam filters are green on the sides and black on top so that doesn't sound right either. Sounds like you have some aftermarket foam filter, which isn't necessarily bad since foam filters are a pretty simple technology. Of course, K&N filters give lots of guys wood but truth is, they flow lots of air because they don't filter the air all that great - but good enough I think as long as you oil them well. Flip a coin? Guess since you already bought the K&N there is no good reason to ditch it at this point.

[Flyboy]

I think the K&N should be fine, they are a reputable company and thier products have proved themseves.

[Flyboy]

I think the K&N should be fine, they are a reputable company and thier products have proven themselves, the cheap junk is what you want to stay well clear of.

[BassCliff]

Hi,

I have both the K&N and UNI air filters for my bike. I go back and forth depending on which one is clean. The way I ride, there's no appreciable difference in performance. Yes, the K&N needs oil or it won't filter well at all. The UNI uses a little oil as well.

Thank you for your indulgence,

BassCliff

[bwringer]

In this application (GS shaftie air filters) I've seen OEM, K&N, and Uni filters, and they all work pretty much identically.

In other words, K&N designed their filter so that it didn't flow better or worse than the OEM oiled foam filter.

If your bike came to you with a K&N, it's fine to continue using. There's little to no reason to run out and buy one, though. It's about $38-$40, and there's no performance or filtering benefit. When it needs to be cleaned, the required K&N wash/re-oil kit is around $15 - $17 last time I looked.

So the K&N filter is expensive to buy and maintain, there's no performance benefit, and its filtering performance is subject to debate. (Personally, I think a PROPERLY cleaned, oiled, and installed K&N does a fine job of filtering, but very few people ever bother to follow the directions...)

An OEM foam filter element (dark gray) runs about $25 - $30, and the Uni foam filter element (green on the sides and gray on the bottom) is about $18 - $20. Neither one of these require special cleaners or oils.

I have two Uni filters. About once a year, I trade them, clean the used one with warm water and dish soap, give it a couple of days to dry thoroughly, and put it back on the shelf for next time. I never bother to oil them -- there's a film of oil that remains after the dish soap, and they quickly get plenty oily from blowby anyway. If you just dump on motor oil as the manual suggests, you'll end up with a badly over-oiled filter and your bike will run rich for a while.