What to do about an air filter

[TwoHundredEx]

See last post




Since I can't use the modified shock mount anymore, I have nearly no room in between my carb and shock. I'm stumped on what to do. Theres not nearly enough space for a clamp on filter, and not enough to run a boot around the shock.
Since the shock is angled I have about 2"s at the top, and about 2.5 at the bottom, maybe a little more/less.
I know it would be kinda redneck, but how would a piece of breathable foam work? My dad owns a mattress manufacturing company so I can get any kind of foam possible. I could shape it so it looks like a super mini UNI filter.
Any other ideas?

[NINJA]

Post some pics and then we'll really know what you're dealing with.

[84honda200s]

yea pics would help allot. but as long as you have a hook up to some foam id say try it. then get filter treatment.

[Mr.Jake]

i use house vent filters for mine, just take 2 and elastic them around the carb. But soak em in gear oil first.

[TwoHundredEx]

i use house vent filters for mine, just take 2 and elastic them around the carb. But soak em in gear oil first.

Do you have any pictures of this? How big are they? They would have to fit over a 34mm carb.


Heres a pic of the area. Couldn't find the stupid tape measure but I'd say theres around an inch at the top and 2.5-3"s at the bottom.
Wondering if it would be better to make the foam flat, or wider at the bottom.

http://i17.photobucket.com/albums/b66/Legacy44/Picture137.jpg

[Dirtcrasher]

Hey bud, we all love your conversion. But, you can't mess around with a filter. It HAS to be adequate. This isn't a half arse built go-cart. Let me ask ya this, if you could change the intake angle at the motor, could another angle squeeze in a place for a radiator hose that adapts to a K+N filter or something.

Give us a back shot of this too!! In other words, a pic of the shock interfering...

[TwoHundredEx]

Hey bud, we all love your conversion. But, you can't mess around with a filter. It HAS to be adequate. This isn't a half arse built go-cart. Let me ask ya this, if you could change the intake angle at the motor, could another angle squeeze in a place for a radiator hose that adapts to a K+N filter or something.

Give us a back shot of this too!! In other words, a pic of the shock interfering...

I was thinking about changing the angle, but I wasn't sure if that would effect the way the engine performed.
I've got a couple rad hoses I can mess around with and I think I'll try that in a few minutes.

I'm not quite sure I understand what you mean about a pic of the shock interfering?
Sorry.. I haven't really woken up yet. :D
You want a pic from the back, or.. from an angle?

[Dirtcrasher]

If you look from the back, I'm guessing that it's the shock spring that your running into. If the carb could be angled a bit more to the left, is there room for a hose or something??

[TwoHundredEx]

Yes it was the shock that I was running into.
I found a rad hose that had a nice bend it in, cut it and this what I came out with.
Still seemed to run okay, but I didn't ride it, just started it and let idle.
There's just enough room to run a hose now. I'm hoping to find one that'll fit the carb, and run a K&N that I have here.


http://i17.photobucket.com/albums/b66/Legacy44/Picture141.jpg
http://i17.photobucket.com/albums/b66/Legacy44/Picture140.jpg

[Kintore]

What i would do is find a real hard bend for a carb boot, what you have there looks better than before. You might be able to squeeze a filter in there thats very long and skinny. Like a long ass KN or something?

[Bryan Raffa]

uni makes small two stage pod filters.. you can get them with a bend in them also..2" round

http://www.polyperformance.com/atvshop/product.php?productid=17447&cat=0&page=1

[TwoHundredEx]

Well I got a carb boot, and filter on it, and now I've got carb problems!
It took forever to start, then when it did the revs slowly went up, and it was fine up to 3/4 throttle, at full throttle it bogs and surges. I thought it was because the carb was angled, but nope. I put it back to stock and did the same thing.
Anyone have any ideas? I did take the carb apart to clean it, but thats all. Maybe it needs to be cleaned again?

[Tri-Z Pilot]

Filter too restrictive causing it to run way rich? Try takin the filter off and see how it runs.

[randall_pitz]

when you cleaned it did you tightin the jets good one may have came loose happen to me once

[TwoHundredEx]

Filter too restrictive causing it to run way rich? Try takin the filter off and see how it runs.

Thats what I thought at first too, but it didn't help. Definitely ran better without it, but still ran like crap.


when you cleaned it did you tightin the jets good one may have came loose happen to me once

Bingo, we have a winner.
Tightened it up and it ran fine for about 5 minutes. Then it started doing it again. Turns out this time, it was because the carb. was on an angle. Put it back to stock it runs like a bat outta hell. I seriously can't beleive how fast this thing is. I can't imagine what a built 250R would be like. I'll definitely try to get a video tomorrow. Nobody else is home, otherwise I would've got one earlier.

[TwoHundredEx]

Looks like I'm back to square on the filter issue though.

[NINJA]

Honestly, that carb angle shouldn't be hurting the performance, unless your bowl isn't sitting level? What would hurt your performance in this instance could be the length of your intake manifold. Is your makeshift intake manifold longer or shorter than your stock one? Also, could you possibly be dealing with an airleak between the carb and intake manifold? It just seems strange that it would run fine for five minutes and then start acting up, almost like vibration affected it?

[TwoHundredEx]

Honestly, that carb angle shouldn't be hurting the performance, unless your bowl isn't sitting level? What would hurt your performance in this instance could be the length of your intake manifold. Is your makeshift intake manifold longer or shorter than your stock one? Also, could you possibly be dealing with an airleak between the carb and intake manifold? It just seems strange that it would run fine for five minutes and then start acting up, almost like vibration affected it?

It wasn't sitting perfectly flat, and the stock intake boot is extremely small, so to make one with any kind of angle would have to be longer. I don't think the engine likes the longer intake. It was a b*tch to start, and when it did, I had to hold at about half throttle until the revs slowly shot up, even when it was warm. When I put it back to stock is started up on the first kick with barely any throttle.
I'm definitely thinking it had something to do with the floatbowl also though. Because it was starving for fuel... it would bog and surge, and then I let off for a second or two, it would fill up and it would rev fine, then do it again, and so on. But like I said, as soon as I put it to stock, it started up and ran perfect.

[Tri-Z Pilot]

Maybe a small k&n like what Harleys use would work. I cant remember if they were bolt on, or clamp on style though. They are only like two inches long from what I remember. They resemble the filter on a 4 barrel car or truck, just a lot smaller.

[McDerry]

You try a boot off a old CR80R? It wraps around the shock.

[TwoHundredEx]

Maybe a small k&n like what Harleys use would work. I cant remember if they were bolt on, or clamp on style though. They are only like two inches long from what I remember. They resemble the filter on a 4 barrel car or truck, just a lot smaller.

Well I have a nice chrome filter from a pocket bike that worked when I modified the shock mount. It's only about 2.5"s long, but it's a little much now that the shock is back to stock.



You try a boot off a old CR80R? It wraps around the shock.
Well my airbox off the bike wraps around the shock too, but it's still too big. I'm thinking of trying to mod the pocket bike one to fit. I doubt it'll work, but I'm up for anything right now.

[Mosh]

Just a thought here.
The 91-92 lt250R had a very squished down air box boot that wrapped around the shock on them.
By looking at the pic you posted,I think it would work for you.
Do you know where a LT is you could look at?

Some motorcylces guys run these caps,that clamp directly on the carbs for air filters.Basically a rubber boot with a steel screen and thin filter on them.That would work for sure,but I do not remember where I seen them available from.
Check some aftermarket motorcylcle places.Dennis Kirk might have them in their streetbike book.

[HEAD09]

yes what mosh said... they use those types on old snowmobiles they only stuck out maybe an inch...

[TwoHundredEx]

Did they look something like this?
I know it's just a vent, but they have UNI filter foam that you can buy in bulk that could be possible be added to it.

http://denniskirk.com/jsp/tpl/cmn/prodlist.jsp?store=Main&catId=311&sort=pricedesc&leafCatId=31101&np=0&brandId=700

[Dirtcrasher]

Those are the ones that go in the filter lid. There IS a crab boot out there that will work, just gotta find it!! Good luck bud and happy holidays!!

You gotta get something on there that is unrestrictive, functional and perfectly air tight. Don't wanna ruin that motor ya know!!

[TwoHundredEx]

Something like these? It says "Intake Tubes Screen", which I have no idea what it means, but it was in the Air Filter section.

http://www.parkeryamaha.com/index.asp?PageAction=VIEWCATS&Category=760

[cr480r]

Angling the carb to the side shouldnt affect performance... Your radiator hose was probably just too large inside or leaked....Even is you have to build a custom manifold its worth it to have a decent filter set-up...

PS. In one of your photos it shows an open crankcase port.. are you running it like that?

[TwoHundredEx]

Angling the carb to the side shouldnt affect performance... Your radiator hose was probably just too large inside or leaked....Even is you have to build a custom manifold its worth it to have a decent filter set-up...

PS. In one of your photos it shows an open crankcase port.. are you running it like that?

Well theres no way to angle the carb and have the bowl sitting flat because of the way bottom end is. The only spot for the carb to sit flat is right in the middle.

The crankcase port... are you talking about the one in the pic next to the shock reservoir? The hose came off while I was taking the engine out, and I forgot to put it back on. I've run it twice like that, but they were short runs just down the street. I didn't think it would hurt it too much. I'll put it back on today.

[cr480r]

The bowl doesn't need to sit flat... I had a funky set-up on my quadracer for awhile that put the carb at a rediculous angle and it ran fine after a float adjustment. Does that open port go in the crankcase? or is it a transmission vent?

[TwoHundredEx]

It's a transmission vent.
I probably could adjust the float and get it to work, but I think I'd rather look for the snowmobile filter first. I don't really ride in harsh conditions, so it should be more than enough. If I absolutely can't find it, then I'll work on the float height.

[cr480r]

If you do decide to build another manifold you may want to keep the inside diameter closer to the original size... The extra volume probably reduces throttle response and the draw on the carb...

[HEAD09]

yes those were it....filters that is....