Air Filter Alternatives + Making Your Own

snikro · Post by **snikro** » Fri Aug 31, 2007 5:35 pm

Has anybody here made their own (imitating stock) air filter? I'm fed up so I'd just like to make one myself and not pay shipping + waiting 2 weeks etc. I want one that I can put in the airbox and not modify anything since I don't wanna upjet and all that yet. I could cut the material to shape but what is a good spongy material that works as good as the stock filter? (also not too restrictive etc and same depth as original element)

GIJoeBob · Post by **GIJoeBob** » Fri Aug 31, 2007 6:54 pm

I've thought of this as well. I am interested to hear what the gurus have to say.

rickc · Post by **rickc** » Sat Sep 01, 2007 12:01 am

You just got a Spree air filter, right? If I had NO alternative I'd probably do something like this: cut a piece of cardboard the right shape to fit over the filter opening inside the Aero's airbox, then cut a big hole in the middle of the cardboard, then staple the Spree filter onto the cardboard (so it covers the hole that was just cut), trim any excess foam around the edges, then stick the whole thing into the Aero's airbox and live with it until I could get the real Aero filter. How's that for ghetto engineering?

snikro · Post by **snikro** » Sat Sep 01, 2007 2:00 pm

Well, I looked at the spree filter and I realized it was just a... sponge. So I said why can't I just cut to size my own sponge of this kind? So I went out and bought a yellow sponge about the same material etc feel of the spree filter, and I plan to cut it down to size and fit it in the airbox. I should still oil it and squeeze it out, right? Also, how can I tell if too much/too little air is being let in, and if particles from the sponge might get sucked into the intake? It doesn't seem likely but it could happen.

rickc · Post by **rickc** » Sat Sep 01, 2007 3:39 pm

Air filters are made of high quality open cell foam. Household cleaning sponges are made of a lower quality foam that has fewer open cells in it, so a sponge would flow less air than a filter. It might still work, but I bet it would make the engine run pretty rich (less air = burn more fuel). If you already have the sponge, there's probably nothing to lose by trying it. Running too rich won't fry an engine like running too lean, it'll just build up carbon deposits faster. There's a few notches of rich/lean adjustment available on the throttle needle holder (search the forum for old posts about it).

snikro · Post by **snikro** » Sat Sep 01, 2007 3:55 pm

rickc wrote:Air filters are made of high quality open cell foam. Sponges are made of a lower quality foam that has fewer open cells in it, so a sponge would flow less air. It might still work, but I bet it would make the engine run pretty rich.

Well, I cut the sponge to shape, (the smooth side shown that came cut from the factory I put facing IN, so nothing would break off and go inside)

CLOSE UP - seems to be a pretty fine material

oiled it up with some 10w-40, squeezed out as much as I could, and it's nice and snug in there. (this was BEFORE oiling - it looks almost the same)

Put the cover on and it turned on without a hesitation and I rode it around and it didn't stop from heat/running lean etc. I'm happy about it but the thing is, it doesn't seem to want to go over 10-15 miles an hour (not sure cause I don't have a working speedo). When you're cruising at about 15 and you have steady throttle input and you wanna go faster, you turn it a bit more and the throttle starts cutting out on you. Full throttle from a stop it's great, but when you reach around 15 it cuts out and wants to go back to idle/less throttle. Also, at the end of my ride I started noticing it was making a lot of smoke, with a slightly bluish tint. I'm thinking the air filter has a little too much oil in it, and it needs to dry out or something a little bit. When I got home I squeezed it out again. Do you think these symptoms are those of a little oil getting in? Or running rich? When you squeeze the spree filter and the sponge, they're pretty much very similar material (not a kitchen sponge with the larger holes) and have the same amount of give.

dukemartini · Post by **dukemartini** » Sat Sep 01, 2007 5:54 pm

i was just at my local home improvement store and im pretty sure i saw a lawnmower airfilter that was a big (big enough to work in a scoot) sponge. i think it was maybe a prefilter for a riding lawnmower? it would be the kind of material that is supposed to be used in an airfiltering application so you know it would work.

rickc · Post by **rickc** » Sat Sep 01, 2007 7:59 pm

snikro wrote:Do you think these symptoms are those of a little oil getting in? Or running rich?

Running rich would make blue smoke, but too much oil would also make blue smoke, so it could be either (or both).

The other symptoms you mentioned sound more like carb problems.

snikro · Post by **snikro** » Sat Sep 01, 2007 10:01 pm

rickc wrote:
snikro wrote:Do you think these symptoms are those of a little oil getting in? Or running rich?
Running rich would make blue smoke, but too much oil would also make blue smoke, so it could be either (or both).

The other symptoms you mentioned sound more like carb problems.

Well I mean I think it's air filter related because the last time I rode it without the filter (stupid yes) I don't remember having that problem of the throttle cutting out. Also, could it be that when you try to go higher speeds, the engine wants more air, but if it's running rich it can't get enough air so it cuts out?

Dac · Post by **Dac** » Sun Sep 02, 2007 1:11 am

take the filter back out and try to get a little more oil out of it. it being so fine might block to much air and not give the motor as much as it needs to perform at top speed

rickc · Post by **rickc** » Sun Sep 02, 2007 1:28 am

snikro wrote:Well I mean I think it's air filter related because the last time I rode it without the filter (stupid yes) I don't remember having that problem of the throttle cutting out. Also, could it be that when you try to go higher speeds, the engine wants more air, but if it's running rich it can't get enough air so it cuts out?

It could do that if it was way too rich. Besides the filter, it could also be the bystarter getting stuck in the up position, or something in the carb.

snikro · Post by **snikro** » Sun Sep 02, 2007 5:38 pm

Last night I tried to squeeze a little more oil out of the filter but didn't get to ride again. I just rode it for the first time today, and when I turned out onto the street I full throttled and it accelerated great and went up to about maybe 20-25 then I backed off cause I had to go down a big hill, and after that the throttle cutting out problem developed once again. I AM thinking trying to squeeze out more oil helped, and I'm going to do it again and try. I also might shave down the filter a tiny bit so it's not so thick. I just wish I could get my stupid speedo working so I could accurately quote the speeds... I checked the cable and everything going down to the wheel and it seems OK, is there anything else I can check for?

snikro · Post by **snikro** » Sun Sep 02, 2007 7:48 pm

I shaved down the filter and squeezed out more oil and it didnt help. When I go out to ride, when I try to accel/full throttle its OK the first time, but after that it starts cutting out at lower and lower speeds/amounts of throttle, and eventually i can't even go 8mph so I have to walk it home. Also, when I'm trying to accelerate and the throttle cuts out, if you hold down the thing at full throttle the engine still sounds like its at idle and then stalls out in a couple of seconds. Any ideas? Also, how do I check the bystarter?

No_Stopping_A_Spree · Post by **No_Stopping_A_Spree** » Sun Sep 02, 2007 9:51 pm

Sounds like you still have to much oil in the filter. if you squeeze more oil out and it works a little better that would make sense..if you have a spare with less/or no oil try using that..it should help

snikro · Post by **snikro** » Sun Sep 02, 2007 10:08 pm

No_Stopping_A_Spree wrote:Sounds like you still have to much oil in the filter. if you squeeze more oil out and it works a little better that would make sense..if you have a spare with less/or no oil try using that..it should help

Is it possible to squeeze out too much? I squeeze as hard as I can but I still can't get much. (If I squeeze it with a paper towel in between it comes off on the towel but I mean I don't wanna take out all of the oil... Also, why does the throttle problem get worse over the course of the ride? I just can't figure it out. I seem to remember that if its cutting out bad and I leave it just idling for a couple minutes, the problem is better but gets back to how it was obviously.

Also, as a test, is taking the sponge out and running with a filter made of a paper towel folded over on itself a few times with the cover ok? I really don't wanna run lean and have heat seize again.