Pod filters instead of airbox

[Hamish Carlson]

I've heard a bit about them for and against. But I want to put some on my bike for the sound and the fact my old airbox is poked. Is it really the case you have to adjust your carbs, as I was under the impression the venturi force would make the needle adjust for any more air let through the channel regardless of what kind of filter is on. Also would it make a difference to diaphragm controlled throttles, as in would it create an uneven air flow stopping needle from lifting and staying up like it should? Any help appreciated,

[SMOKEU]

There is a possibility that it could run lean, but that really depends on how restrictive the factory air box is.

[CookMySock]

The airbox is an important part of the resonant induction system. Some types of carbs will brainfart badly if you even take the air filter element out of the airbox, let alone remove the airbox completely.

http://www.google.co.nz/search?q=airbox+Helmholtz

Steve

[jonbuoy]

Depending on how exposed they are on the bike they can be a bitch if they get wet not to mention the difficulties of balancing the carbs. With an airbox all cylinders are"sucking" from the same filter - as the filter blocks with time all the carbs are restricted - with separate pods each cylinder is sucking from a different filter with the filters blocking up at different rates it will throw the balance out. I wanted to go pods but decided to stick with the ugly airbox.

[hayd3n]

whats wrong with the old air box??
couldent you modify or fix it?

[F5 Dave]

Like the millions before you, you will have all sorts of drama that won't be an easy jet change to fix. Your best bet is go see a wrecker with your old parts & see what you can get. Pay him whatever he asks if he can get you back to somewhere near std. Getting the box in & out will be a drag but often removing a couple of screws fo say teh mudguard will give you vital clearance.

Filter foam can be bought by the sheet if need be.

[CookMySock]

Filter foam can be bought by the sheet if need be.From where?

Steve

[hmmmnz]

yeah don't do it, ive done the whole pod filter thing on loads of bikes, and i have never got it right on the first or second jet change,
its taken me weeks and up to 10 jet changes and a dozens of tweaks to get the bike running as well as stock (or slightly modified stock)
then in the end half the time ive gone back to the air box, because all you are doing is just using more fuel, for a mythical 2- 3 hp somewhere in the rev range, that you barely notice any way,
its an exercise in futility, but go for gold, may as well learn the hard way :D
have fun

[F5 Dave]

From where?

Steve
A bike shop. Ask them to get in some unifilter foam sheet from the distributors. It can then be cut &/or glued carefully with small amounts of superglue.

[The Pastor]

Go for it, you can get it tuned to run well, and it will sound WAY better. (custom is way better than stock) but no huge real world gains.

Things to think about.

Jetting - find out from someone who has done it before and buy a range of jets around his reconmendation
dyno tune - very good idea.
carb balance - make sure you get somone who is good to do it, huge differance in a good balance and an average balance (including the fuel mixtures etc)
mounting - how are you actually going to attach the pod filters? 1 per carb? or a custom manifold with 1 large pod filter?

Go for a k&n filter they are expensive but they are good.




OR you could go my way and not run any air filter ;)

[F5 Dave]

Well there is some great advice. So tell me how much do you think this will cost? What do needles cost? Main jets?, Pilot jets? K&N pods? Dyno time?

on a mid 80s 400.

[FJRider]

Well there is some great advice. So tell me how much do you think this will cost? What do needles cost? Main jets?, Pilot jets? K&N pods? Dyno time?

on a mid 80s 400.

Your advice in post #6 in probably the most logical. Most wreckers are online ... let the fingers do the walking. Overnight couriers do the rest....

[Pumba]

I think everyone els has said all the logical stuf. I am just curious as to what you have done to a mid 80's bike to cause its moulded plastic (?) air box become poked?

[onearmedbandit]

OR you could go my way and not run any air filter ;)

And how does that work out for your engine?

[Hamish Carlson]

I think everyone els has said all the logical stuf. I am just curious as to what you have done to a mid 80's bike to cause its moulded plastic (?) air box become poked?

I was curious about the in's and out's of it all, there are a fair few hurdles to overcome from the sounds of it to get anywhere near standard performance and does sound damn expensive and not worth the time. The old airbox manifolds are poked, I can have a thrash with some duct tape to seal them back up, and also get some new foam for the filter. I had no idea of the complications pods impose, hence the question. I was on the lines of thinking it might have been quicker to get 2 small cheapish pods, instead of having the runaround of fixing the old airbox. Engine is still out of bike so had the option of going either way before I put it back in.

[F5 Dave]

Yeah the manifold rubbers can be a drag, but if a wrecker can match up some old ones that aren't cracked then you're ok. Then find something a bit bigger, maybe a smooth glass jar & soak the rubber in hot hot water & after a min force the rubber on the end to stretch back to std.

[Hamish Carlson]

Yeah the manifold rubbers can be a drag, but if a wrecker can match up some old ones that aren't cracked then you're ok. Then find something a bit bigger, maybe a smooth glass jar & soak the rubber in hot hot water & after a min force the rubber on the end to stretch back to std.

Smart advice, thanks, I should be able to give that a thrash. I'll post a pic of the airbox later on, for you guys to see what I'm dealing with.

[geoffm]

What bike? Impulse and FZR400 I have done open carbs in the past. The intake noise on the Fizzer was deafening.

[Hamish Carlson]

twin cylinder gsx.

[The Pastor]

not had any trouble yet

[R6_kid]

And how does that work out for your engine?

My TRX was like that when I bought it. When I took the carbs off and looked down the intact tracts you can see that there is a buildup of dirt and other crap just before the valves. In the long run it's going to ruin the seal on the valves, and can potentially fuck rings etc if anything decent in size gets through. I'll be stripping and rebuilding the head soon to clean it all up and get the bike running mint.

[onearmedbandit]

Yeah not exactly ideal running an engine without an aircleaner in place.