Fixing something thats not broken - Drop-in Air Filters

[setasai]

I am not looking for a performance increase (though I would not be against it persay) nor am I looking to do any carburator work.

Bike is currently shimmed 2 washers w/ snorkel out and stock exhaust.

I like it the way it is BUT the stock air filter has gone through a few clean/oil cycles that is starting to break down. I thought that since I have $10 promotional credit and some amazon rewards points that I'd try out a k&n drop-in filter (purchased for $2) expecting little to no changes in performance. NOT TRUE, popped it in and the entire powerband felt flat. I'm assuming that its because the K&N flows a tad more air and hence leaned out everything.

So my question is what to do what to do? I'll most likely return the K&N but what should I do with the stock filter replacement issue?

[CThunder-blue]

buy a stock replacement? Try putting the snorkel back in with the K&N?

[setasai]

Originally Posted by CThunder-blue

buy a stock replacement? Try putting the snorkel back in with the K&N?

Attempted the snorkel reinstall. After cursing for a few minutes I gave up. K&N is already on its way back to amazon. Love amazon returns... and prime.

I think I'll just go look for a stock replacement and be done with it. The reason I went with the K&N was because I had some cleaner and oil for the K&N back when I used it for my car that I no longer have.

Does the pipercross foam filter flow more/less air than stock? Maybe I'll try that just for kicks too.

[CThunder-blue]

Foam filters are not a good idea. They allow more dirt to entire the engine. Some guy did a comparison with a vacuum with different filters and found the foam type to not work very well. It's not scientific, but did show a healthy amount of dirt being ingested.

[rockNroll]

Originally Posted by CThunder-blue

Foam filters are not a good idea. They allow more dirt to entire the engine. Some guy did a comparison with a vacuum with different filters and found the foam type to not work very well. It's not scientific, but did show a healthy amount of dirt being ingested.

Gauze (k&n) let a lot of dirt through as well. I have found that the type of oil used on a foam filter makes all the difference. You want the oil to be nice and tacky.

[DaBlue1]

Originally Posted by setasai

...Does the pipercross foam filter flow more/less air than stock? Maybe I'll try that just for kicks too.

The Pipercross filter does flow more air than the stock filter. The thing I like about the Pipercross is the 3 layer design and the tacky dirt retention additive (which is way better than regular oil) used to help trap the dirt. Since having mine in, I've been totally satisfied with it and the performance of my bike. I too have done the shim and snorkelless mod. There are a few others on here that have seen a slight improvement since installing a Pipercross air filter.

As with anything you will always have those who like other products and may have good arguments for their choices, however I think the jury is still out on which type filter is the absolute best. I believe that each type of filter has it's advantages and disadvantages depending on the application and design. You may just have to check it out yourself.

[setasai]

Originally Posted by DaBlue1

The Pipercross filter does flow more air than the stock filter. The thing I like about the Pipercross is the 3 layer design and the tacky dirt retention additive (which is way better than regular oil) used to help trap the dirt. Since having mine in, I've been totally satisfied with it and the performance of my bike. I too have done the shim and snorkelless mod. There are a few others on here that have seen a slight improvement since installing a Pipercross air filter.

As with anything you will always have those who like other products and may have good arguments for their choices, however I think the jury is still out on which type filter is the absolute best. I believe that each type of filter has it's advantages and disadvantages depending on the application and design. You may just have to check it out yourself.

Thanks. I actually did a seach after this post and saw your review on it. Sounds like a good replacement. What I hated most about the k&n was how difficult it fit because it had a rubber rim. I think I'm going to give the stock air filter 1 more clean/oil cycle and then order the pipercross. I suspect the major change in performance was from not being able to get an airtight seal on the cover because of the K&n's fitment.

[CThunder-blue]

Wait, you originally said that it flowed too much air causing a lean condition on the entire RPM band. Now you want another filter that will do the same thing?

[setasai]

Originally Posted by CThunder-blue

Wait, you originally said that it flowed too much air causing a lean condition on the entire RPM band. Now you want another filter that will do the same thing?

I suspect the lean condition was caused by the fitment of the K&N not the extra flow that you get from the filter itself. I am currently running a little rich and so I assumed that a little bit more flow would make it better but the K&N drop-in is rubber and was pushing the cover open. Who knows, I could be wrong and in the end I'd still need to mess with the carbs. I havent entirely decided yet.

[CThunder-blue]

I don't see how the fitment of the filter will affect your AF ratio. My bike has a K&N and is jetted properly too. Maybe it's time to jet your carbs?

[setasai]

Originally Posted by CThunder-blue

I don't see how the fitment of the filter will affect your AF ratio. My bike has a K&N and is jetted properly too. Maybe it's time to jet your carbs?

The K&N was a bit difficult to close the cover to the airbox. Looks like a possible leak meaning wayyyy more airflow than necessary leading to a lean condition. Atleast that's my assumption. In anycase, I guesss I could jet my carbs but I'm not really interested in fiddling with it yet.

[CThunder-blue]

Did you ever compare the K&N to the old one you had to see if the dimensions were a little off?

[setasai]

Originally Posted by CThunder-blue

Did you ever compare the K&N to the old one you had to see if the dimensions were a little off?

Didnt have to... It's not that it didnt fit, it was just such a tight fit that if you dont really snug it in all the way, the cover gets pushed out a little and leaves a crack. Doesnt matter. K&N is already returned. No biggy. If I go with any other aftermarket air filter, I might need to add a shim or something regardless. No need to figure out anything about the K&N anymore. Thx anyways.

[boytoy101]

maybe ur putting the k&n filter in a wrong way and having trouble inserting the knn filter is u might not used the lubricant that it has with the filter when u bought it...im using k&n filter also works fine with me....

[setasai]

Originally Posted by boytoy101

maybe ur putting the k&n filter in a wrong way and having trouble inserting the knn filter is u might not used the lubricant that it has with the filter when u bought it...im using k&n filter also works fine with me....

Maybe but I made sure to use the grease and put in the filter exactly how the directions say. Like I said, it fit... it was just soooo snug that the filter cover was bending itself outwards and I'm "assuming" that there was an air leak or maybe the filter flowed so much air that it leaned out the A/F mixtures.

Regardless, I wasnt in the mood to deal with either issue and so I left it at stock... for now. I figured, if I return it now, I can use the money again later to buy something else. It's not like I lose the promotional credits if I return it.

[ScorpionNinja]

Originally Posted by setasai

Maybe but I made sure to use the grease and put in the filter exactly how the directions say. Like I said, it fit... it was just soooo snug that the filter cover was bending itself outwards and I'm "assuming" that there was an air leak or maybe the filter flowed so much air that it leaned out the A/F mixtures.

+1

I also have a K&N filter and I cannot push it in anymore... also after my bike sitting all winter, this spring I noticed when I took the air filter COVER off (3 bolts) the cover itself was "Warped" slightly, cuz the K&N filter pushes back against it. I removed/shaved Off some of the plastic (1/16th") in the middle of the cover, so the K&N dont push against it!

[Boom King]

The rubber border of the K&N is what pushes up against the cover. By design, the OEM filter does as well but the difference is that being foam, it has more give. If you look on the inside of the cover, there is a raised lip or edge where it pushes against the filter to form a seal. I suspect that any foam type filter would fit fine since the cover was designed for that type.

BMC makes a filter that is high-glow and is the wired cotton gauze type similar to the K&N. The difference is that the BMC has a foam border around the filter and I assume this was done by design to fit against the air filter cover without pushing against it like the K&N.