K75RT Air Filter

[DRUDOLPH148006]

I have a new to me 1992 K75RT and have a question about changing the air filter.
The Clymers book says to remove quite a bit of the fairing and the gas tank.
Have any of you with this model come up with an easier way to do this?
Could the tank be lifted in the rear without removing all the tank fittings just
enought to lift the top of the air filter cannister? I was told that the bike has
a k+N filter. Have you had good luck with these as long as they are cleaned
once in a while or would it be better to go back to a BMW filter? Thanks.

[nh7robmw]

I would go back to the stock paper BMW filter---I believe K&Ns let in too much junk into the system.

I haven't changed mine yet but I've hear from others here that you don't need to remove the tank, just lift the back end up a bit.

[DRUDOLPH148006]

Thanks for the input. I did a price check for the BMW filter at A+S Cycles and they
want $42 for it. A check at IBMWR's website has a Purolator air filter #AF3389
that will fit the K bikes, I'm sure one of those filters from an auto parts store
would be quite a bit cheaper than $42. Are "BMW" filters that much better ? or are you paying for the name?

[35634]

The Purolator filter may not be available anymore. The K&N gets a bad rap on this
forum, (saw one tech article that dissed it pretty bad) and some people had problems
getting it to fit right. I like mine, had in for the last 170K and the motor is just fine.
I'd clean the K&N and not worry about the theoretical advantages of the BMW filter.

[jebner]

Let's see, I have a K&N Air filter in my 1987 BMW K75C with 56,000 miles that I've owned since 1996, my 2002 BMW K1200RS with 21,000 miles that I bought new, a 1985 Porsche 944 with 250,000 miles that I also purchased new 24 years ago, and a 1994 Dodge Ram 1500 pickup with 142,000 miles that I bought used in 1999 with 54,000 miles on it at the time. So is that enough reassurance????

As for installing it on your K75, the only difficult part was getting the clips to snap close. I've removed the gas tank many times, it is not hard. Be careful and don't smoke!:doh

[roncooper]

You shouldn't need to move the tank. Are you aware that the filter edge is exposed before you remove the clips? The top of the housing only has to be moved a small amount for the filter to slide out.

I vote for OEM filters. They are oversized and last a long time.

The right lower must be removed-10 screws and 2 10mm bolts.

[PHMarvin]

Hi, DRudolph,
You may keep the K&N air filter in your bike, removing it to clean and re-oil, as long as you wish. It's your bike. I prefer the filtering ability of the stock air filter. It is so oversized that I remove it annually, tap it on the floor to knock loose whatever will fall out, then reinstall it for another year. I may decide to change it at around 50k miles. Brian Curry thinks they're good for 100k miles unless you've gone through a plume of volcanic ash or some heavy dust storms.
I have a perfectly good K&N, used maybe 10k miles then cleaned and reoiled, in my parts drawer. If anyone wants it, I'll sell it for $20 plus shipping. If he picks it up, I'll give him the remainder of the bottle of K&N Filter Oil. I live in El Paso, TX.

[roncooper]

I also have a K&N in Belton,TX. Make me an offer. We are leaving tommorrow on a 2 week trip and I won't have a computer.

[DRUDOLPH148006]

It sounds like people are happy with whatever they are using and tend to want
to stay with what they are using. If the bmw filters are good for 50,000 miles
by tapping them on the ground and blowing them out with low pressure, then
It really wouldn't be to my advantage to buy the K+N cleaning kit. Where I live
{Klamath Falls, Oregon} there is about a 7 month riding season and I doubt if
I would ever put more than 2,000 miles a year on the bike. I'll find out how much
the cleaning kit costs compared to the $42 for a new BMW filter. Thanks for the
information.

[35634]

Air filters are not much of an issue with K bikes. My K&N was part of a CC mod back
in 88 or so, kept it because I like the looks. I still have the original filter, it's an
'original litter K75S' original filter if anyone wants it (needs to be tapped on the
ground a couple of times) :D

[Kayseventyfive]

I prefer the filtering ability of the stock air filter. It is so oversized that I remove it annually, tap it on the floor to knock loose whatever will fall out, then reinstall it for another year. I may decide to change it at around 50k miles. Brian Curry thinks they're good for 100k miles unless you've gone through a plume of volcanic ash or some heavy dust storms.


+1 on that. If you have a manometer, you can check yours every so often up through the gears. I have a Filter Minder that I use for checking all our family vehicles. It has saved a lot of unnecessary element changes. A lot of diesel trucks and stationary engines are recommended not to change the filter until the FM says to. Gas engines don't lose power or economy until above 20 inches H20 differential.

.

[deilenberger]

Back to the original question. I don't have a manual, so this is from memory.

On an RT - part of the fairing blocks removal of the filter. You have to remove the knee pad on the right side (the black vinyl looking part your knee hits..)

Two screws at the top are located in the storage pocket near the bottom lip. One screw at the bottom. There is a snorkel going from the front of the fairing to the side of the airbox - held on by one screw. It's easier to do this job if you remove the snorkel. Remove screw, tug it out of the bottom of the airbox.

Once that's out, you have to try to release all the clips on the airbox. Look at the one that's visible - it's the clue how they work. They pivot off, IIRC - from the bottom - pull out, and then release the top.

Once all 4 clips are off (you're doing this blind on most of them) - you have to get the K&N out. That's more of a challenge than the BMW filter since K&N didn't mold a release lip in the back edge of the filter, you you have to get the entire top of the airbox up off the fliter about 1/8" - then wiggle it out and toward you.

Putting the new BMW one in is a bit easier - it has a part of the lip removed on the back edge so it slides in and pushes the upper part of the airbox up. Wiggle it in, make sure it's fully seated all the way around then spend an hour or so getting the 4 clips on the airbox back on. One or two will come off completely - that's par for the course - be persistant and it will go back together.

The snorkel has to be put back - it goes into a grommet sort of thing in the airbox, wetting it with some water will make it slide back in without pushing the grommet into the airbox. Once in position - put the screw that holds it back in place.

Put the kneepad back on and you're done.

Then fogeddaboutit for 40,000 miles or so.

[BuddingGeezer]

Once all 4 clips are off (you're doing this blind on most of them) -

P.

There are only 3 clips, 1 in the front right side/ 2 in the rear. the left rear clip is the hard one for me. I would position the clip then use a screwdriver to close it. I never could get all 3 clips to snap using a K&N.

Ralph Sims

[DRUDOLPH148006]

Thanks for all the opinions on the question of staying with the k+N or going
back to the BMW filter. I'm leaning toward going back to the BMW filter. It sounds
like it may be easier to change and they seem to last a long time, I assume that
the engineers at BMW put as much thought into the air filter as they did the
rest of the bike. I've never had such a well put together bike. It sounds like a
bigger job than it actually will turn out to be, with all the systems that have to be
put together in a small space, I quess not everything can be easy to get to.

[deilenberger]

There are only 3 clips, 1 in the front right side/ 2 in the rear. the left rear clip is the hard one for me. I would position the clip then use a screwdriver to close it. I never could get all 3 clips to snap using a K&N.

Ralph SimsRight you are Ralph (I said it was from memory.. no manual and no more K bike in the garage..)

http://www.realoem.com/bmw/showparts.do?model=0514&mospid=47868&btnr=13_0517&hg=13&fg=20

Three PITA clips.. :blush

[lostboy]

Air filters are not much of an issue with K bikes. My K&N was part of a CC mod back
in 88 or so, kept it because I like the looks. I still have the original filter, it's an
'original litter K75S' original filter if anyone wants it (needs to be tapped on the
ground a couple of times) :D

This is actually a Luftmeister accesory, not CC Products. CC/San Jose didn't approve of this mod.

[35634]

This is actually a Luftmeister accesory, not CC Products. CC/San Jose didn't approve of this mod.

Oooooops... Guilty of spreading miss-information. In my defense, that was many
Budweisers ago :beer and my grey matter has been numbed by that blown-out Luftmeister can on my K.

AND it wasn't a Luftmeister accesory, it was a Luftmeister accessory :stick :D

[BuddingGeezer]

Right you are Ralph (I said it was from memory.. no manual and no more K bike in the garage..)

http://www.realoem.com/bmw/showparts.do?model=0514&mospid=47868&btnr=13_0517&hg=13&fg=20

Three PITA clips.. :blush

I figured that was it, but I sure didn't want someone looking for that 4th clip. The left rear clip is hard enough.

Ralph Sims