Hi everyone,

Doing some maintenance on my recently purchased CBR600F4 (1999), and noticed the sub-air cleaner has compacted "sand/dirt" in the hose inlet (or outlet?) on the sub-air cleaner housing. See the attached pictures. It's the light-brown stuff inside of the inlet/outlet that I'm talking about. Is this sand or dirt? If so, any ideas how it could build up and get so compacted inside there? Or, is this some sort of ceramic-y sandy air filter? Just wondering what you guys know before I start cleaning it out. It's compacted in there pretty good... which is why I'm hesitant to clean it out (filter of some kind... although that doesn't make much sense.)

See the pics!







There's no way that's normal. I'm going ahead and cleaning it out. If it turns out it's some fancy filter, I'll just have to buy a new one - but I'm thinking that's not the case, it's just clogged as hell! Weird how it would get so compacted though... ideas?

 

Well it may very well be a dense foam which is supposed to be in there as a filter but judging from your air filter LOL I bet all of them need to be cleaned.

 

Nah, this is definitely compacted sand/dirt. I poked around and pieces started crumbling. It could be that the sub-air filter inside there (assuming there is one in there) got clogged and just started building up. That's probably the case.

I purchased 2 sub-air filters for underneath the main air filter. Didn't think I'd be able to find odd parts like that, but BikeBandit.com had them. They're two thin trapezoidal-ish oiled foam pieces, housed underneath the main air filter by plastic covers. Those had a bit of sand/grit on them. They were also "sticky" and "crumbly", so I replaced them. I didn't know about this third sub-air cleaner... I think the same foam filters would fit in the plastic housing shown above...