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gvkohl
02-13-2007, 10:25 PM
I recently purchased a 2003 Kat 600. I am doing all my maintenance and changes while the weather is cool. They guy I bought the bike from had installed a Uni filter. It is very dirty and needs changing/cleaning.

My question is ...should I replace it with a stock filter, a K&N or another Uni? I am not going to be putting a lot of miles on the bike. This is a second bike and will get ridden but not high mileage.

I've been hearing more and more the steers me away from the K&N.

All advice and opinions are appreciated.

KatanaSoldier
02-13-2007, 10:32 PM
Is it beyond cleaning? To save some bucks, you can use air to clean it good unless it is real bad. I would stick with another one of those or stock. Some use the K & N but I am not sure if that would require any other modifications to work right.

BarMatt80
02-14-2007, 08:15 AM
cyber has a big write up of pros and cons on the stock paper filter and that of the K&n. I can't find it now, it is 8 am and I haven't been to bed yet. I'll find it when i wake up around 4 or so. Um....If you do go with a k&n filter that is like the stock filter, you need to use the small donut.

steves
02-14-2007, 08:30 AM
How many miles are on the bike?

I put a K&N on the Bandit and it ran crappy.

My new jetkit instructions say to use a paper filter.

I wouldn't run a k&n with out at least a jetkit. Maybe a slipon too.

arsenic
02-14-2007, 01:00 PM
Yeah, if you want a new air filter get a stock one. If you run K&N your gonna want to jet the cards. It real simple, the K&N will let more air in, your gonna want to match that with more fuel.

KSlawman
02-14-2007, 05:18 PM
I have a uni filter on my GS1000. Is yours a foam type element or some sort of material? The reusable ones can be cleaned. If yours is just foam, then you can wash it in hot water and dish soap. I think the K&N and other reusable types can be cleaned with a special cleaner. Not sure if kerosene would work or not.

reconstyle
02-15-2007, 12:35 PM
I have a k&n on my 05 600, with a dyno jet kit, and it runs like crap. I'm switching to Ivan's kit and going back to the stock filter

ZukiFred
02-15-2007, 01:09 PM
I have a unifilter as well, it is a reusable filter unlike the K&N it dose not increas the airflow so no rejeting required. All you need to do is get the Uni Service kit, it will include the cleaner and the oil to apply after cleaning.

http://i12.photobucket.com/albums/a240/ZukiFred/Pictures163.jpg

The CyberPoet
02-16-2007, 03:27 AM
The uni filter does increase air flow (and they say as much on their sites -- which is part of why there's a restrictor donut that comes with it), and is supposed to be washable, at least their all-foam ones.

The short answer: IMHO, 98+, go back to stock. I have a stock OEM filter here ready to ship if you need one, $32 plus actual postage to you (I also carry virtually all of your other maintenance needs and many upgrades for the kats, from OEM spark plugs/oil filters/parts to tire valves & raised chrome Katana emblems -- see that KR member's specials forum for details).

The complete answer:
There are seven air filters for the Kats available that I know of. Note that list everything here is strictly IMHO, and there will be people who disagree with me. You have to make your own decisions as to what's right for your particular needs. Personally, what I value most in any filter is the filtration ability, because better filtration means longer engine life, and for me that triumphs even performance issues.

:arrow: K&N airbox filter
Advantages:
+ will flow more air.
+ [PRE-98 ONLY] Good tied into an aftermarket exhaust if jetted to match, to get the more performance out the engine by increasing airflow.
+ can be washed, reoiled and reused. Especially good on bikes with worn rings because getting wet won't kill it as large quantities of oil get scavanged from the crankcase venting into the airbox.

Disadvantages:
- will drop the vacuum level, may require richening up the jetting to compensate.
- [98+] No performance benefit demonstrated, dis-recommended for 98-06 Kats by both Ivan (Ivan's Performance Products) and Marc (of FactoryPro), the two leading jetkit designers for the Kat, as well as myself.
- doesn't filter quite as well as the OEM filter does (oil trapment through wider pores never filters as well as smaller pores in a thicker substrate).
- You'll have to own it about 50k miles before you hit break-even in terms of cost (replacing stock filters vs. cost of K&N filter plus wash/oil kits at the recommended intervals).
- Requires use of a airbox-opening modifier donut (two provided) to offset the higher air-flow rate; if it pops out of place, gets installed backwards or you use the wrong one for you set-up, the bike acts up badly.
- Most owners don't wash/reoil theirs as often as they should (yet another maintenance task).

:arrow: K&N pod-style filters
Advantages:
+ will flow more air.
+ eliminates the airbox, letting you move other things into the space if needed.
+ [PRE-98 ONLY] Good as part of a stage-3 upgrade tied into an full aftermarket exhaust (including aftermarket headers) if jetted to match, to get the absolute highest performance out the engine possible.
+ can be washed, reoiled and reused.

Disadvantages:
:!: Never use on 98+ !!!
- [pre-98] will drop the vacuum levels heavily, must be matched to a full aftermarket exhaust & aftermarket jetkit to compensate. PIA to jet to match, typical owner takes a long time and a few hundred bucks to get it done after tinkering and then giving up & turning over to a shop with a dyno & exhaust sniffer.
- [98+] No one ever gets their jetting matched right all the way across the RPM range to these filters, but many have wasted months and hundreds of dollars (even over a thousand in one case I know of) trying before giving up and going back. Don't even try it. You were warned.
- doesn't filter quite as well as the OEM filter does (oil trapment through wider pores never filters as well as smaller pores in a thicker substrate).
- You'll have to own it about 48k miles before you hit break-even in terms of cost (replacing stock filters vs. cost of K&N pod filters plus wash/oil kits).
- eliminating the airbox means a requirement for a vent-stack breather filter to be added to the bike as well, higher crankcase vent-gas explosion risk (minor, but there).
- Most owners don't wash/reoil theirs as often as they should (yet another maintenance task).

:arrow: Uni-Flow Foam airbox filter
Advantages:
+ will flow more air than even the K&N airbox filters, use of K&N style airbox restrictor ring recommended to help offset this effect.
+ can be washed, reoiled and reused.
+ weight savings over K&N and over the OEM filter (not sure how critical that could be considered on a 520 lb wet bike).

Disadvantages:
- same as K&N airbox filter basically, with even less filtration due to pore size and shape. See above.

:arrow: Uni-Flow Foam pod filters
Advantages:
+ will flow more air than even the K&N pod filters.
+ eliminates the airbox, letting you move other things into the space if needed.
+ [PRE-98 ONLY] Good as part of a true track-oriented (drag racing for example) stage-3 upgrade tied into an full aftermarket exhaust (including aftermarket headers) if jetted to match, to get the absolute highest performance out the engine possible.
+ weight savings over K&N and over the OEM filter (not sure how critical that could be considered on a 520 lb wet bike).
+ can be washed, reoiled and reused.

Disadvantages:
:!: Never use on 98+ !!!
- same as K&N pod filters basically, with even less filtration. See above.


:arrow: TriFoam filters
Advantages:
+ Filters better than the Uni-foam while still using a foam technology. Unlike Uni Foam, TriFoam uses three different pore sizes (in layers) in their filters, which improves the grab rate.
+ Will flow more air than K&N, about the same as UniFlow at most RPM ranges.

Disadvantages:
:!: Never use on 98+ !!!
- intended specifically for racing applications normally, where time between engine-teardowns is minimal & weight savings are critical.
- No restrictor donuts provided, so jetting must be matched.
- same as all the other oiled-filters basically. See above.

:arrow: EMGO stock-replacement air filter
Advantages:
+ looks just like the OEM air filter from the outside (doesn't if you disassemble it [destructive disassembly])
+ flows more air
+ Cheapest filter available (least amount of upfront-cost).

Disadvantages:
- Fewer pleats, larger pore size, filtering matting thinner, won't filter as well as the OEM filter.
- A couple Kat owner's 100% stock bikes suddenly ran like crap when using this filter because it pushed their stock jetting too lean.
- Looks just like the OEM filter from the outside, so spotting it as a source of trouble can be virtually impossible; I had to look at receipts to figure it out.
- Ruined if it gets wet (water, oil or fuel). Not normally an issue for a healthy bike, but can become one during hard spills, hurricane-force winds, bad petcock + stuck carb float, or worn rings.

:arrow: OEM Suzuki Filter.
Advantages:
+ Best filtration I've seen to date for the Kat. Filters smaller particles than any other filter, meaning the longest engine life and the least amount of fine sand, etc. going into the engine.
+ Cheaper intial purchase price than any of the above other than the EMGO (but can't be washed/reused);
+ Design means dirt & debris gets sucked to the bottom of the inbound side, leaving the majority of the filter material clean even after taking in a bunch of debris.
+ Can be vacuumed or blown-out to partially clean (limited effectiveness, vacuum only the inside).
+ Will outlast the service interval by a factor of 2 or 3 usually if vacuumed/blown cleaned every oil change (Mojoe got 88k out of his first one!).
+ Not the contriction point in the breathing of the 98+ engine;
+ [98+] Best solution for use with aftermarket jetkits for highest torque performance (street-usable power).

Disadvantages:
- Ruined if it gets wet (water, oil or fuel). Not normally an issue for a healthy bike, but can become one during hard spills, hurricane-force winds, bad petcock + stuck carb float, or worn rings.
- Costs more over 48k miles than the competition if changed according to the factory schedule (every 18 months or 11k miles, whichever comes first).
- [Pre-98] Can be a flow-constriction point when mated to aftermarket headers and jetkit.

Thought of the night:
If a filter flows more air, so much so you have to use a restrictor plate/plug (donut) with it to offset that flow change to keep the bike from acting up, what advantage did you gain in performance?

Cheers,
=-= The CyberPoet

gvkohl
02-16-2007, 07:33 PM
Thanks of all the info. Now I feel like I can at least make an informed decision........

Next question.....how hard is it to change myselft.....does the tank need to come all the way off. From what I've read here, it looks like pulling the tank is a bit of a pain.

Is there a shortcut of any kind?

The CyberPoet
02-16-2007, 08:29 PM
NOTE: EDITED FOR CLARITY, CORRECTNESS

Look at this picture from my website (98+ Airbox assembly):
http://www.motorcycleanchor.com/katana/trinc/air_box.jpg

Where it says remove two bolts, remove them. There is also a bolt on each side of the bracket that screws into the airbox -- remove them as well.

Now you can lift that bracket up (with the tank still bolted to it) an inch, and then slide it & the tank backwards about 2". Now you can lift the rear of the tank & bracket up high enough to get at the phillips head screws for the air filter.

Do not simply push the tank straight up and out of the way -- make sure you slide it backwards some before lifting it the rest of the way, as the front of the tank has two thin metal C-channels on it that grab into the rubber stopper right behind the steering head to hold in place, and you don't want to bend them out of shape (fairly easy to do by accident).

// END OF EDIT //


8 minute job for a first timer, 2 minute job for a pro.

Note that if you are going with the K&N or Uni-Flow, you need to oil (commonly called "charging") their filters before install. The night before is the best, so excess oil can flow out if you overdo it.

Cheers,
=-= The CyberPoet

garykohl2
02-17-2007, 12:01 PM
I have to disagree with all of you. I have a 2000 600 Katana and I'm running a K&N filter and a Leo Vince slip on and mine runs great. I did not even have to rejett !! It runs strong with great throttle response, good power, and never stumbles. Maybe I just got lucky with mine but I stand behind the K&N