Some Kawasakis use oiled foam air filters as standard.
foam air filter
- Thread starter richard shaw
- Start date
To state the bleedin' obvious, the performance gain from changing the air filter depends on how restrictive the OEM filter is in the first place. I have changed to K&Ns on some bikes and got an improvement, but I think the GS standard filter is pretty good so it's no worth using an alternative to the standard.
in any case trading a small and dubious performance gain for an almost certain reduction in filter efficiency doesn't seem a good bet to me.
in any case trading a small and dubious performance gain for an almost certain reduction in filter efficiency doesn't seem a good bet to me.
Bendy toy
Registered user
I agree on performance gain but not on oiled foam filters being worthless. Many bikes use them as standard with no risk to the cylinder bores. Brother's Aprilia Pegaso has about 50K on the clock with zero engine problems. Filter is oiled foam. Mother's Honda CB125S did 65K mostly between 7500 and 9000 revs. Failed cam bearings (standard design issue) did for it but cylinder bore was fine. Guess what - oiled foam air filter.
K&N however is a thin layer of J cloth cotton so can't cause much air restriction or much filtering.
The R1200 would gain more performance by chopping off the inlet tube and adding a venturi spout. But it will be noisy.
K&N however is a thin layer of J cloth cotton so can't cause much air restriction or much filtering.
The R1200 would gain more performance by chopping off the inlet tube and adding a venturi spout. But it will be noisy.
Enduro bike verses a used every day all year round bike that gets an air filter change every 12k miles and an engine which is expected to cover over 100K miles, and regularly does, without any work.
Yes, absolute bollox.
Or, as they say, different horses for different courses.
Bendy toy
Registered user
So how does that fit with Hondas and Aprilias doing high miles on oiled foam filters?
K&N I'm sure are worse than snake oil but oiled foam soon clogs up when over oiled so the pores can't be huge.
K&N I'm sure are worse than snake oil but oiled foam soon clogs up when over oiled so the pores can't be huge.
I have just pulled a barrel off a R1200RT ( to helicoil a head stud), the bike has done 140K miles with a K&N filter.
The hone marks in the Nikasil bores look as if they have only done 5k miles, piston and rings are Ok.
K&N don't claim to be a good filter just flow more air. The surface area of a K&N is far smaller than a stock filter yet they flow more air which hints towards the filtering efficiency.!!
I run a K&N on my own bike in the UK , but when heading for dusty destinations such as North Africa I fit a paper filter for the Trip.
I don't think there is any performance difference, I run a lambda offset of 13.8 to1 so a little richer or leaner either way wont be noticed.
Just looking at both sides of the coin.
The hone marks in the Nikasil bores look as if they have only done 5k miles, piston and rings are Ok.
K&N don't claim to be a good filter just flow more air. The surface area of a K&N is far smaller than a stock filter yet they flow more air which hints towards the filtering efficiency.!!
I run a K&N on my own bike in the UK , but when heading for dusty destinations such as North Africa I fit a paper filter for the Trip.
I don't think there is any performance difference, I run a lambda offset of 13.8 to1 so a little richer or leaner either way wont be noticed.
Just looking at both sides of the coin.
I really really don't know, as i only pass a comment on my own personal experience, and i only work on BMW's.
And i've seen, with my own eyes, far to many bikes with oiled foam filters fitted and shite downstream of the filter.... could be dozy owners not using enough oil, or the wrong oil, who knows.
But i've never the same thing on a paper filter.
I have no interest in what owners want to fit. I'm only passing on my own personal experience, over many years, and on many hundreds of different BMW's.
Totally agree there is no substitute for paper filters if there is no water involved.
I was just surprised at the good condition of this 1200RT bore.
I competed in competitive safari and Hill Rally`s for 12 years and had to use K&N filters with a foam over filter with motocross filter oil.( Because of water)
The amount of crap that got through was frightening.
I think I have just talked myself into going back to paper filters full time.!!!
I was just surprised at the good condition of this 1200RT bore.
I competed in competitive safari and Hill Rally`s for 12 years and had to use K&N filters with a foam over filter with motocross filter oil.( Because of water)
The amount of crap that got through was frightening.
I think I have just talked myself into going back to paper filters full time.!!!
I'm yet to meet a BMW mechanic (manufacturer or indy) who has recommended anything other than the standard paper filter. Mines down 111,000 miles through everything from a dry and very dusty 1000 mile run on the Dalton through to very heavy rain through to just pissing about locally.
I've thought a couple of times about K&N etc etc before a big trip but every time I ask grown up, they always say use the standard one. Fucking about oiling a filter is not something I want to be doing on the road.
I've thought a couple of times about K&N etc etc before a big trip but every time I ask grown up, they always say use the standard one. Fucking about oiling a filter is not something I want to be doing on the road.
Did I say anything about enduro bikes?!
Did I say anything about Enduro bikes?
London Mole
Registered user
Venturi spout sounds VERY interesting ... How would you do it? Cutting through the bodywork?
Bendy toy
Registered user
So called s velocity stack. Chop the intake tube short and fit a flared end like this
http://en.m.wikipedia.org/wiki/Velocity_stack
http://en.m.wikipedia.org/wiki/Velocity_stack
Deleted account 211025001
Registered user
- Joined
- Feb 3, 2005
- Messages
- 8
- Reaction score
- 10
I did that to my 1200, and fitted a K&N - made feck all difference that my arse could feel.
Went back to a paper filter prior to a Maroc trip and never bothered fitting the K&N again
Andres
bikemad
Registered user
It does make an induction roar sounds much better than standard as others have commented
I think with the exhaust/PC it's a lot better than my 1st GS 
I fitted a new alloy mesh on intake cos the old one was tired.
Bendy toy
Registered user
Mine has a long tapering intake tube with a small diameter inlet end and a small diameter slightly flared trumpet mouth. Cutting it shorter would reduce the tube restriction and give a larger diameter. Fitting larger bell mouth would ease the airflow into the tube. However it will only be noticeable a maximum power (maximum air mass flow) so don't expect a huge difference.
London Mole
Registered user
I take it a Defender-style snorkel would totally screw up the air/fuel ratio? Anyone got one?
sykospain
Registered user
foam versus OEM air filter
As far as I can see, the only possible reason to change over from the OEM airbox filter system to the on-throttle-input-tubes foam filters, is the greatly simplified 2-day job of tearing the bike in half for dry clutch maintenance.
Only people like Neil, who does the entire job single-handed, is able to put the bike back together without uttering one single expletive because of the infernal struggle to correctly re-fit that sodding airbox, which of course works perfectly as per original design parameters and in addition not only catches any over-enthusiastic engine overfill oil, but also re-breathes the motor's crankcase fumes to keep the environmentalists happy - neither of which jobs the foam filters can do.
As far as I can see, the only possible reason to change over from the OEM airbox filter system to the on-throttle-input-tubes foam filters, is the greatly simplified 2-day job of tearing the bike in half for dry clutch maintenance.
Only people like Neil, who does the entire job single-handed, is able to put the bike back together without uttering one single expletive because of the infernal struggle to correctly re-fit that sodding airbox, which of course works perfectly as per original design parameters and in addition not only catches any over-enthusiastic engine overfill oil, but also re-breathes the motor's crankcase fumes to keep the environmentalists happy - neither of which jobs the foam filters can do.
Similar threads
