sub air cleaner

Hi all,

I am new to this forum, so apologies if its a question asked before. I have 3 bikes, two of them Hondas. An '81 CX500 and a  2002 CB500 ( and a little yamaha xv535 which i have bitched up and bobbed ) I have owned this CB500 for 4 years and it had a restrictor fitted when i got it, which I never bothered to remove even though i didnt need it and I wasnt really planning on doing 85MPH plus anywhere on uk roads anyway so I left it. I have just however rebuilt a spare engine for it and will be swapping them over to rebuild the one on the bike as it has a grumble from the transmission. So - the restricter comes out very easily once the carbs are off, but I am at a loss as to what the sub air cleaner does !!!. I have bought a Honda original filter for it, tiniest bit of foam for 11 quid, but its original and as its part of the carbs didnt want to bodge it. what on earth does the sub air cleaner do ?, is it filtering air in, if so why, or is it filtering air out for emissions reasons ?. I do maintain this bike very well like I assume everyone other biker on here and can pretty much do anything on this little old bike, but never really paid attention to this part of the carb.

cheers and good to meet you all.

Rich

Hello Spanner Monkey!

AFAIK the sub air-filter doesn't really do anything; I'm pretty sure that it is is a breather or pressure relief vent, the filter is just to stop crap getting in.

It's a bit late after you have spent 11 quid on a new one, but: a lot of people just cut up a washing-up sponge and stuff that in instead! So far no ill effects have been reported...

LOL. thanks so much for the reply. That's what i thought, but at least its all original, dents an all... Carbs are one of those things left to the very experience mechanics i feel so as a hobbyist i did think just order the right bit before i gum it up with something i shouldnt. should have had more sense really, but the rest of the bike has cost me next to nothing to repair and maintain so the old girl doesnt dent my pocket that much. Great little forum this. these bikes are so dead easy to work on. 

cheers

I use an old cut up cotton sock for my sub air filter - better than nothing at all

Just found a post that'll explain it. http://hondashadowacetourer.yuku.com/sreply/81843/Sub-Air-CleanerWhat-is-it39s-function

Given it's position over the engine I assume it draws in warmer air to the carbs for better cold weather running.