xr400 K & N Air Filter- jetting changes?

[sport]

Thinking about fitting one; does it slot straight in and need any carb changes?
Ta

[Xman]

Originally Posted by sport

Thinking about fitting one; does it slot straight in and need any carb changes?
Ta

Yes it goes straight in, but unless you are running a highly modified Supermoto XR... I can't think of a reason to fork out the extra, as there is practically no extra hp to be had over fitting a good quality foam filter and plastic cage.

I can understand the 'Bling' factor for MaxPower car owners but you cant see it locked away in a XR airbox.
Plus it is harder to clean and more expensive to oil.
Plus it will not stand up to water ingress as well as an oiled foam airfilter in an off road environment.

I always say running a K&N on anything is almost like running without an airfilter as they do breathe very well but the acid test is to run your bike down the road without an airfilter and see if it makes any difference. If you think it improves the power, and you don't mind the above hassles...try it but I use a 'Twinairfilter' and filter skin both heavily oiled in an off road environment, and don't notice any power difference at all.

Plus I think you'll find that nearly all Hondas and most Jap carb fed bikes, are jetted on the rich side anyway to err on the safe side, to prevent seizures/running hot etc. So using a free flowing air filter makes them run about right without major jetting changes anyway.

[Kes]

Yes you will need to increase the jets.

1. KN = more air

2. More air without more fuel = running lean = runs hotter .

3. More air + more fuel = more power .

4. Without a race full system power will be negligable .

For the cost of parts with the XR basic bhp I do'nt think you would reach more than another 4bhp = not enough bang for your buck .

Ran KNs on jap multis for years without proplems if you do not upjet it will more than likely run like a sack of crap .

[sport]

Thanks guys.
Just saw one advertised cheap and thought about it. I'll forget it if it means jetting changes.
Ta

[416cc]

I fitted one to my XR400, & have never looked back. I wrote which jets I fitted together with the other mods in the 'sticky' at the top. It has been a worthwhile modification, but luckily I had some good info to start with by looking on the net for guidance. This filter together with the exhaust mods hasn't done so much for top end power but has made a worthwhile better 'feel' in the mid-range & bottom end. Even a friend who has essentially the same bike as I have was surprised when he rode the two bikes back-to-back.

But it will never be as good as my KTM...

[stueydo]

I have a 4x4 that i use for competitions, it used to have a K&N air filter in it, but with the conditions it goes through it needed replacing after 6 months. So now, as with most of the others i use a standard filter because that costs £8 to replace, whereas the K&N cost nearly £60.

As 416cc said, if you want power, think orange.