Air Filter

[twisted threads]

I herd that a 400ex K&N air filter is the same for the TRX 450r?? Is that true?

[4punksdad]

the aftermarket 400ex filters look alot alike............however, the stock filters are NOT the same.

[2004TRX450R]

the way the back of the stock filters are supported is very differetn. However I don't think I'd run a K&N on a 450R because the cylenders are nickasil and if you get any dirt in there and mess it up you will be buying a new cylender because you can't have it bored. K&Ns work good for flowing a lot of air but not so great at filtering it so you will get crap in the cylender.

[ROGERS]

Doesn't fit. Tried it.

[twisted threads]

Originally posted by 2004TRX450R
the way the back of the stock filters are supported is very differetn. However I don't think I'd run a K&N on a 450R because the cylenders are nickasil and if you get any dirt in there and mess it up you will be buying a new cylender because you can't have it bored. K&Ns work good for flowing a lot of air but not so great at filtering it so you will get crap in the cylender.
Are you going to keep your stock air filter?

[ml450r]

Originally posted by 2004TRX450R
the way the back of the stock filters are supported is very differetn. However I don't think I'd run a K&N on a 450R because the cylenders are nickasil and if you get any dirt in there and mess it up you will be buying a new cylender because you can't have it bored. K&Ns work good for flowing a lot of air but not so great at filtering it so you will get crap in the cylender.
Keep your k&n properly oiled you'll be fine, and a 400ex K&N filter fits fine. I have it in mine right now.
Merrill

[2004TRX450R]

Originally posted by twisted threads
Are you going to keep your stock air filter?

Yup I'm keeping my stock filter.


Originally posted by ml450r
Keep your k&n properly oiled you'll be fine, and a 400ex K&N filter fits fine. I have it in mine right now.
Merrill

Even properly oiled it won't do the best job in filtering.

[kgbg]

The 400ex filter does fit, I have one in mine as we speak. You might be having trouble with it hitting the breather tube from the crankcase, just slide it out a little towards the pipe, or cut about 3/4" off the end in the air box.
I have always run K&N, with no air box and outerwears on my 400ex. I ahve come to the conclusion that the K&N does fine in the sand, its particles are big enough to keep them out, but I got a foam wrap for the filter as well, then run a outerwear over that. I have no airbox, so this helps me sleep better at night.

[rtyfz450]

k&n s work just fine, I have run one on the 44ex I have had since 98 and never had any cylinder wall scratching due to sand and we ride mostly at glamis. On the topic of boring out the cylinder. yes you can do it and you don't have to buy a new one. the just re-"nikasil" your cylinder after they bore it. they can even put a sleeve in then nikasil it to make the bore the same even though I would recommend a sleeve because you loose some of the heat transfer properties.

[dhines]

Sand is one thing. Powdery-fine dust is another. I have not had great success with K&N's in the dust of the Mid-South.

[2004TRX450R]

Originally posted by rtyfz450
k&n s work just fine, I have run one on the 44ex I have had since 98 and never had any cylinder wall scratching due to sand and we ride mostly at glamis. On the topic of boring out the cylinder. yes you can do it and you don't have to buy a new one. the just re-"nikasil" your cylinder after they bore it. they can even put a sleeve in then nikasil it to make the bore the same even though I would recommend a sleeve because you loose some of the heat transfer properties.

Yes you can have it re nikasiled but by the time you either do that or have a sleeve put in it you are about the same price as a new cylender. Either way it is expensive. They don't nikisil a sleeve though. Installing a sleeve also hinders your heat transfer. That is the reason they use nikasil in the first place.

A K&N might work fine but it doesn't work great. It will filter the bigger stuff like sand granuals but it won't filter the finer dirt.

[400ex4ever]

If K&N is not the best for the small dirt particals. Which one is?

[twisted threads]

Originally posted by 400ex4ever
If K&N is not the best for the small dirt particals. Which one is?
Thats what I want to know also.

[2004TRX450R]

Originally posted by 400ex4ever
If K&N is not the best for the small dirt particals. Which one is?

Stock or foam equivilant as long as it is properly oiled and I don't mean sprayed out of a can on the filter and that is it. To properly oil a filter the oil has to be worked completely through the filter. Anywhere the filter doesn't have any oil it won't filter properly.

[sjw1176]

are support rings needed when using a k&n on a 450r

[rtyfz450]

Yes you can have it re nikasiled but by the time you either do that or have a sleeve put in it you are about the same price as a new cylender. Either way it is expensive. They don't nikisil a sleeve though. Installing a sleeve also hinders your heat transfer. That is the reason they use nikasil in the first place.

I can't agree with the pricing you are saying for a rebore and nikasil costing more than a new cylinder. my friend has had a 2001 cr250 rebored about 3 times and it cost him 350 bucks each time with the Nikasil, piston, rings, intalled . You cant tell me that the cylinder costs 350 dollars with a new piston, rings and installed. yeah I know this is a different engine but my friends z400 is pretty much as close as you will get and that would cost 140 for the nikasil coating and it takes 2 weeks.
No he doesn't have a K&N and that is not the reason for the rebuilds. Yes they can nikasil a sleeve and no it is not a good Idea because like I said and you repeated, the heat transfering properties can be deminished.
If you don't like K&Ns that is fine, to each his own but they do filter good and with an outerwear it works damn well. By the way silicate is the worst for your engine and sand riding puts you at the worst risk for damage if your filter works poorly. the fine silicate dust and sand out there is much worse than any dirt riding.

[2004TRX450R]

That sounds pretty cheap for the renickisiling. seems I've heard it was over $200 for it and it isn't usually as good as the factory stuff. It usually isn't quite as much as a new cylender but it is to the point that you might as well get a new one so that you know it is right. It will be better quality. I've run K&N filters on most all of my ATVs in the past and they just don't filter as well as a foam filter in dusty conditions. They do an OK job but not a great job. If you plan on tearing your engine down and rebuilding all the time such as in pro raceing then sure it doesn't matter as much. The added air flow and power out weigh the cost but if you want a filter for a bike that you want some longevity out of stick with a foam filter.

[Hammer trx450r]

Im sure the sand is bad but some times if the track isnt wet enough it turns into a dust bowl that is sooo thick that my airfilter is clogged. Without a properly oiled foam wrap you are sure to suck it up. K&N is about air flow so there is a fine line on what it can catch. It isn't a miracle filter by any means.