Air filter service

[TrapperAH1G]

Servicing my AF today, K&N.  Did it about 10K miles ago, figure do it the same as the rear end maybe?  Anyway, may have to change that plan.....it was really dirty.  Now to the main point.....there was a small "pooling" of oil (pretty sure) and maybe some gas mixed in, at the bottom of the air box.  Not just a coating on the surface, a puddle so to speak.

Thoughts?

Is this the crankcase breather tube issue?  I was planning on cleaning it out tomorrow after I finish the filter work.

Thanks

[hubcapsc]

Thoughts?

Use an OEM filter 

-Mike

[Jess from VA]

The air intake to the air box is in the rear.  It is not uncommon to pull the tank and airbox cover and see the rear quarter/third of the air cleaner dirty, and the rest look new.

K & Ns may be OK filters, but when the oil drys out it's not cleaning very well at all.  And given the interval many choose between changes (or cleaning) (a year or two), it's much better to run an OE filter, which never stops cleaning.  

It's possible the drool tube never got drained, it's possible the bike got dropped and left on it's side for awhile, it's possible the prior owner overfilled the crankcase on oil change.  BTW, the drool tube can really get full of crud on long rain rides (like all day getting somewhere).

Some oily residue may be normal, but I've never heard of one as crummy as you describe.

[Bagger John - #3785]

It's possible the drool tube never got drained,

I'd definitely verify this.

And:

Use an OEM filter

Mine's been back-ordered from the manufacturer since 4/20. (Coincidence?) I always keep a spare or three hanging around just in case, but...come on Honda. It ain't like this is a complete final drive unit.

[TrapperAH1G]

Finished up today.  Cleaned the box, oiled the dry filter and installed.  Drained the drool tube, had quite a bit in it.

Rode down to my trusted local MC mechanic's shop and ordered 2 OEM filters, $25.00 each.  Said they'd be here in 10 to 14 days.

We'll see.

Question:  When I removed the tank this time I took a much closer look underneath.  The fuel line from the tank is about 4" long and then there's an in-line filter.  To get to it, I'd have to remove the air box.  Don't think this is standard.  Doesn't seem to be a problem, but seems I've read this could be an issue.
 Guess I'll get to that next time I go in to change the filter.  Replace or remove?

[CoreyP]

I have the same "Why is it there filter". I left mine for now but I don't see why I need it and it is another point of failure. I would rather have single fuel line, no joints. 

[Jess from VA]

Without a fuel filter and all stock, there is just enough stretch in the lines to shove a piece of 2 by 4 on edge under the tank in back, and that gives you room to use both hands for hooking and unhooking things.  One of those headband lights is very useful, and keeping one with the bike is a good idea too.  Better than the maglight in the mouth with drooling too.

[F6Dave]

https://www.nicoclub.com/archives/kn-vs-oem-filter.html

If you're considering a K&N, you might want to read the above test.

[Willow]

https://www.nicoclub.com/archives/kn-vs-oem-filter.html

If you're considering a K&N, you might want to read the above test.

Or you might not.  Lots of Valkyrie riders run K&N filters.  I do.  My Standard has over 200,000 miles.  The K&N has served well.

You can also find reports on why a not made for motorcycle tire won't work on the back of a bike.  We have millions of miles on bikes with those tires on the back.

I like the K&N.  I won't be going back to an OEM air filter.   

[dago mooserider]

I’ve always wondered why so much gloom and doom about K&N’s on this board. ….do they filter as good as oem? - no. Does it matter? -also no. Unless you are riding your valk in the baja 500, it will last longer than you will. I’ve had K&N’s on both my valks and while I dont have nearly mileage willow does, I’ve had zero issues and I do believe there is a very slight power bump. Also they let out a sweet intake growl that combined with aftermarket exhaust sounds amazing 

[F6Dave]

I hesitated to post that test because some people get personally offended by any criticism of K&N. However, I thought that anyone thinking about switching might be interested as it shows why manufacturers don't install 'serviceable' oiled media filters on their vehicles.

The internet is full of K&N filter complaints. Most focus on two issues: damage to MAF sensors (which our carbureted Valkyries don't use) from the filter oil, and visual evidence in the intake tract that excess dirt is passing through. But those are mostly anecdotal stories. If you want precise data you often need to get out of the real world and into a controlled environment. To measure horsepower you connect to a dyno. To determine the condition of your oil you don't look at color of the dipstick, you send a sample to a lab.

That's what the 'Spicer' test did. Rather than analyze filters pulled from an engine, they ran an ISO 5011 test on 9 competing filters using a machine that flowed test dust (a specific mix of particle sizes) at a constant rate until the filter clogged.  Clogging was defined as restriction causing a pressure drop of 10 IN-H2O.

The results showed a clear pattern. Two oiled filters (K&N and Uni) were compared with 7 traditional paper/syntyetic filters, like Purolator, Wix, and AC/Delco. The best filter ran 60 minutes and let .4 grams of dust through.  The worst (K&N) only ran for 24 minutes and let 7 grams through. So the best filter passed .0067 grams of dust per minute, compared to .29 grams for the K&N.  That's a ratio of over 43:1!

It's easy to see why more dirt gets through the K&N. It has only 29 pleats, while the Honda filter has 43, or 48% more. With significantly less surface area the K&N can only flow more air by having larger pores. And larger pores mean larger dust particles. Just hold a K&N up to the light and you'll see how porous it is. While these photos are of GL1800 filters, the more rectangular Valkyrie filters have the same pleat density and surface area.

The less efficient filtration of oiled media filters is fairly well know. But the big surprise to me was that they clog up faster, which is possibly due to having less surface area. I used K&N and another oiled filter in the past. I didn't like the clean/dry/re-oil routine, but I believed the hype that they lasted longer, and considered one for mt GL1800 since the filter change is such a chore. Now that I know conventional filters last longer (and filter better) there's no way I'll install a brand that needs to be serviced MORE frequently.

[Willow]

Rather than just swallow what some test supports I am inclines to look at real world results.

Like I said before I've hundreds of thousands of miles on K&N filters.  How many miles do you find it'll take to cause damage to a Valkyrie engine.

As stated the airflow is increased.

As for service interval the OEM recommends replacement at 12,000 miles.  The K&N suggests clean and service at 40,000 miles.

If I get 400,000 better performing miles from my Valkyrie(s) it will probably outlive me.

Do what makes you comfortable but don't badmouth what you don't like and suggest your prejudice to less experienced riders unless you have some real life proof.

[John Schmidt]

My experience is in the FWIW line of thinking. I kinda echo Carl's thoughts here, I've used K&N on every bike I've owned in the last 45+ years. That includes a couple GL1000's which I ran well over 100k miles each, one GL1100 and one GL1200...both ran in excess of 100k. Then my GL1500 '92 Wing which I traded with a bit over 70k for my 2-wheel Valkyrie(currently at 72k) about March, 2002. Somewhere along the line I even had I believe it was a CB(?)350, I know it was a 350 just don't recall the prefix. And also a 2 cylinder 500 I picked up for a song which is the only reason I bought it, cleaned it up and rode it to/from work for a couple years plus some personal local excursions, sold it with nearly 40k miles. For that matter, I've even used them in some of my cars. The point is, I've never had an issue with any of them in use. If they passed a lot of dirt at the rate suggested, I venture to say after 125k miles those bikes(and cars) most likely would have started to show oil consumption...something I've never experienced. Dave, this is by no means a criticism of you, I'm merely stating my experience. 

[Jess from VA]

The K&N suggests clean and service at 40,000 miles.

I've used them in bikes, cars and a truck. 

I never waited 40k to service them, they dry out far sooner than that.  More like every 6 months.

I prefer the OE filters in the Valks because I don't like servicing the K&N (as often as I think it needs it).

In Vtwins and cold air car/truck kits, it takes one minute to take one off to service.  The Valk takes somewhat longer. 

[h13man]

Service time and frequency having a K&N on the my Valk from original owner, I went back to OEM. The intake roar, how in the heck could you hear it with Cobra exhaust? I also run a Pingle petcock thus making it easier to do this service. It's hard to fault Honda OEM design. By design the K&N definitely flows more and roar's but being cleaner air overall? To each their own.

[Bagger John - #3785]

An oil analysis which targets silicic composition and percentage is the definitive way to go here. Start with fresh oil and fresh OEM air filter, run until the change interval is met. Save a sample. Repeat the test with the same oil type and weight, this time swapping the air filter for a freshly serviced K&N. At the change interval, collect an oil sample then send both for a blind analysis - along with a third, unused sample of the same oil for control purposes.

Numbers don't lie. Whatever lets less silica into the intake stream is what I'd use, especially on a bike whose cylinders cannot easily be removed for re-boring.

[F6Dave]

This is a tech forum. People post lots of data and numbers here. There are discussions about tire construction, sizes, and mileage. Oil threads cover chemistry, brands, viscosities, oil change intervals, and UOA results. Some members talk about fuel mileage, which seems kind of pointless if you ride a Valkyrie. So you'd think if someone chose an air filter with a reputation for high airflow capacity, but at the expense of allowing more dirt into the engine, they might be interested in a test that precisely measured how much dirt flows through their filter. Apparently not! A typical response reads something like this: I don't need no stinking numbers! What counts is 'real life experience'.

Years ago, when manifolds looked like household plumbing, and tiny air filters were tacked on as an afterthought, improving engine performance with better breathing was easy. But that changed rapidly as government imposed stricter and stricter fuel mileage standards. Manufacturers had to improve engine efficiency, and better breathing was low hanging fruit. A bigger airbox and filter cost far less than adding, say, variable valve timing or forced induction. So manufacturers quickly upgraded intake systems to use much larger filters. Honda was an early leader on this front. The Valkyrie's filter and airbox are larger than those in many small cars. Things like the intake horn placement inside the box show how thoroughly Honda engineered airflow.

Times have changed. People don't use toilet paper oil filters any more. 'Free flowing' exhaust systems may sound good but rarely improve performance -- just ask someone who installed 6-into-6 pipes on a Valk. And few modern engines are capable of flowing more air than their stock filters can supply.

[F6Dave]

An oil analysis which targets silicic composition and percentage is the definitive way to go here. Start with fresh oil and fresh OEM air filter, run until the change interval is met. Save a sample. Repeat the test with the same oil type and weight, this time swapping the air filter for a freshly serviced K&N. At the change interval, collect an oil sample then send both for a blind analysis - along with a third, unused sample of the same oil for control purposes.

Numbers don't lie. Whatever lets less silica into the intake stream is what I'd use, especially on a bike whose cylinders cannot easily be removed for re-boring.

That would be interesting. I recently ran a UOA on my Tourer with 177,000 miles. If someone wants to run a test on a K&N filtered Valk, Blackstone still charges just $30. Then we could compare results.

[Bagger John - #3785]

That would be interesting. I recently ran a UOA on my Tourer with 177,000 miles. If someone wants to run a test on a K&N filtered Valk, Blackstone still charges just $30. Then we could compare results.

Mr. Heisenberg takes issue with your approach.

Use the same bike, same brand/weight of oil...the only variable should be the air filter.

[luftkoph]

Manufacturers put in many hours perfecting an intake system, and we can’t help ourselves from messing with it, I’m guilty on more than one count.

Here’s a heck of a nice guy that knows a bit more than I ever will about this stuff, its a little glimpse into what it takes.
https://patents.google.com/patent/US20090008181A1/en

[luftkoph]

Automotive[edit]


Helmholtz resonance finds application in internal combustion engines (see airbox), subwoofers and acoustics. Intake systems described as 'Helmholtz Systems' have been used in the Chrysler V10 engine built for both the Dodge Viper and the Ram pickup truck, and several of the Buell tube-frame series of motorcycles.

The theory of Helmholtz resonators is used in motorcycle and car exhausts to alter the sound of the exhaust note and for differences in power delivery by adding chambers to the exhaust. Exhaust resonators are also used to reduce potentially loud and obnoxious engine noise where the dimensions are calculated so that the waves reflected by the resonator help cancel out certain frequencies of sound in the exhaust.