Air Filter: K&N or OEM...


Information and questions on GL1500 Goldwings (1988-2000)
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Elmobile
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Air Filter: K&N or OEM...

Post by Elmobile »



I usually much prefer OEM part over after market, especially when it comes to filter of any kind!
So I had replaced the K&N air filter with an OEM early on when I was getting my 1990 SE ready to go back on the road.
Recently I did the "cardboard" test, which consist of blocking the air inlet, but nothing happen. I could block it 100% and the engine would keep on running as if nothing happened.
The body of the OEM filter is made of hard plastic. So I thought of putting the K&N filter back in as its body is made of rubber.
Now when I re-did the cardboard test with the K&N, it is working as it should. The engine stalls if I block the inlet.

It kind to tell me that the air box is warped and the hard body of the OEM filter does not seal correctly...
Is it supposed to be a seal in the groove of the original box?
Should I keep the K&N filter or try to seal the OEM in place?

Any thought? Cheers...



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AZgl1800
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Re: Air Filter: K&N or OEM...

Post by AZgl1800 »

there is supposed to be a Gasket below the airbox to the carbs...

it gets thrown away sometimes.
my '94SE was that way when I bought it, unknown to me of course, until I replaced it.

In my case, the K&N sealed tight inside the airbox, but the box had a big gap between it and the carbs....
I come to find that out when I was riding in the dry power sands near Parker and Lake Havasu, Arizona...

the engine bogged down so bad, it would not go...

pulled the air box off and the slides were jammed, would not move up or down... filled with powdered sugary sand. Had to use some carb cleaner, and needle nose pliers to wash the slides and pull the slides up/dn until they freed up good.

bought an OEM filter and gasket the next day for it.
~John

'02 GL1800
2009 Piaggio MP3 250cc

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Elmobile
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Re: Air Filter: K&N or OEM...

Post by Elmobile »

Could have done that first... Went on Babbitts online fiches and there is a seal in both the bottom half and the uppper half. Part # 17213-MN5-300.
Well that solve this part of my question.

What about K&N versus OEM.

Should I relub my K&N (I do have a K&N cleaning kit on hand) or get a couple of seals for the OEM?

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AZgl1800
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Re: Air Filter: K&N or OEM...

Post by AZgl1800 »

Personally?

I will not subject my bikes to a K&N filter ever.
too much fine grit goes right down the cylinders... no way you can prevent that from happening, unless you buy the OEM air filter.

the OEM will last at least 50,000 miles and still perform like brand new.
the only exception to this, would be if you were treating it like a dirt bike, and I am pretty sure you won't be.
.
~John

'02 GL1800
2009 Piaggio MP3 250cc

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thebruce
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Re: Air Filter: K&N or OEM...

Post by thebruce »

+1 for oem. Or pretty much any other decent paper filter.

I have seen too many K&N filters that lost their floof that would easily let through coarse sand in a few spots. Not a good thing.
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blupupher
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Re: Air Filter: K&N or OEM...

Post by blupupher »

My bike came with a K&N, and I have found it a touch large to fit in the grooves. Not something I would set out to buy, but since it has it, I am keeping it for now.
I have found that installing the filter on the top cover first then putting that down on the housing makes it easier to get a good seal.
1994 GL1500 Goldwing SE

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CrystalPistol
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Re: Air Filter: K&N or OEM...

Post by CrystalPistol »

Both our 1200 when I bought it in 1995 and our 1500 trike we bought in 2004 already had K&Ns in them, I never had reason to change them, I did clean & reoil lightly occasionally. Sold the 1200 in 2019, sold the trike this year back to original owner, both still had K&Ns. I did find a K&N in my '07 F150 when I bought it in '07 but I took it out and put a OEM in it.
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Viking
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Re: Air Filter: K&N or OEM...

Post by Viking »

K&N filters were all the rage for years back in the 80s and 90s, and this did overflow into the early 2000s. Amsoil made a washable re oilable foam filter during the same period. Amsoil discontinued theirs as a bad idea more than twenty years ago, but there are still K&Ns being sold. When they are first used, the K&N filters let more air through, due to the way they are made, but when they start to dirt up (which of course is soon, due to the fact that oil holds the dirt coming in) they get to a point pretty quickly that they choke off the air supply. OEM filters, being dry, take a lot more dirt in them to choke off the air to the engine. OEMs will last longer between filter changes, but K&Ns can be washed and reoiled. They are almost never reoiled to the original spec. Also they are commonly oiled before they are fully dry, and this allows the oil to run off into the carbs. As mentioned above, I would never use a K&N if an OEM was available for the application. If you want to wash and oil a K&N filter every 5K miles, they are likely a superior product for you. For anyone riding a GL1800, that is a lot of work for that few miles.
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Elmobile
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Re: Air Filter: K&N or OEM...

Post by Elmobile »

Thanks for all the comments.
I am going to reuse the K&N filter for the remaining of the season and will get the seals for next summer. No big trip planned as we are to stay in our Atlantic bubble...
I just cleaned it and let it dry overnight. Will put it back in tomorrow!
Now I am curious to see if I can feel a difference!

Cheers

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Elmobile
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Re: Air Filter: K&N or OEM...

Post by Elmobile »

So the K&N is back in after a good clean-up, overnight drying time and relub. Should do me for the rest of the season. I have added getting the seals for the air box on my to do winter list... ;)
Going back to the "cardboard test" I am looking for comments from those who know how to analyse it...
I wanted to make sure that my air box was tight. So I slowly closed the air intake while the snorkel was still out. Much easier to see what's happening.
If I close it completely, the engine dies right away. That's good! However I can close that air intake almost all the way before the rpm begins to drop ever so slightly. There is only 3/8 of an opening left at that time. Seems to be very small to me. I can even rev it to 1500 rpm and it is happy to keep running!

Would that be an indication that the engine, mixture screws, is running rich? I had the carbs synchronize not long ago and I also asked to have the mixture screws adjusted. The fellow told me that the plugs look good so it did not want to mess with the mixture... They are opened 3 turns which is where they were when I rebuilt the carbs. Later I found out that the initial pre-set should be 2 turns only. That could explain why I get a poor mileage even so I pull a sidecar :shock:
I guess I am going to check the plugs, the easy to get at, myself...

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Elmobile
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Re: Air Filter: K&N or OEM...

Post by Elmobile »

Went to the shop real quick to look at #6 plug...
Not sure what to think. The electrodes seem to be OK while the outer body is quite black.
So here are some pictures. Looking for some input. Should I close my mixtures screws by 1/2 turn to get them closer to the pre-set value?







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thebruce
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Re: Air Filter: K&N or OEM...

Post by thebruce »

That looks just fine to me, if not a little on the lean end. I'd bet the last time the bike was running it didn't go far.

Those mixture screws really only have effect at idle and a little above.

The only way to get a good read on a set of plugs is to give the motor a good workout, and then kill the motor as soon as you are in the yard, no idling, nothing.

If the bike starts and idles fine, and does not fall on its face if you snap the throttle open, I would leave the mix screws alone.

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Elmobile
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Re: Air Filter: K&N or OEM...

Post by Elmobile »

Correct thebruce. The bike did run idle for a while when I was playing around with my air filter. Went for a ride today and will check it again.
I guess I will leave everything alone for now. Good throttle response as far I as know, taking in consideration that this is the only 1500 I have ever ridden. So to be honest I do not know for sure how it should be able to pull! ;)

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Elmobile
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Re: Air Filter: K&N or OEM...

Post by Elmobile »

Here is a picture of plug #6 after a 50 miles + run.
Look about the same to me.

I am not going to touch anything for now...



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thebruce
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Re: Air Filter: K&N or OEM...

Post by thebruce »

That looks just fine, if not a little lean. If the bike runs well I wouldn't change a thing with the mixture.

This makes me want to check my plugs to see what they are seeing for mixture. Maybe over winter I will rejet a little fatter to see if she pulls harder or just drinks more.
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Re: Air Filter: K&N or OEM...

Post by XJSRider »

This is all not goldwing specific:

I don't think reading plug is good for setting idle jets. Unless maybe they are grossly out of spec. Especially after going for a ride I believe you are reading more of the main jet at that point and its effect on the plug than just idle jet.

I've always started tuning them by feel... trying to get the best off idle response. Blipping throttle while turning out idle screw quarter at a time. There is a method too where you set your idle up and play with the screws seeing which way the idle goes. I usually set to factory standard then make changes till throttle is nice and snappy.

To compare the right vs left side one of those insta read thermometers at the exhaust port if the temps are close then the air/fuel ratio is close same. Same AFR does not necessarily mean the same number of turns on the idle screw.

IMO the slickest way is weld extra O2 bungs to header and use a wideband O2 sensor and gauge... set them both to around 12.8, or whatever AFR gives you best throttle response off idle.

Also the picture on reading the plugs with the white=lean that beautiful toasted marshmallow brown = good, and black = rich: The plugs in my toys with EFI always end up looking like the white plug. A slight tinge of brown because I'm looking for it. Maybe because they run closer to AFR 14.5, but I've also heard detergents in the gas prevent the browning compared to back in the day.

I'd rather be rich on idle jet than lean.



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