The New And Improved Unofficial R65 Forum V2

Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: Bob_Roller on August 13, 2010, 08:13:18 PM

Title: Flat Air Filter
Post by: Bob_Roller on August 13, 2010, 08:13:18 PM
Just wondering how many owners are aware of the fact that the flat air filters that started with the '81 model year, have to be 'modified' to properly fit the air box ?

If you look at the cut outs in the molded filter body, they don't match up with the cast part of the air box that has the spring clips used to hold the filter and top in place .

You need to trim out a bit of the filter to get it to set correctly on the air box .
Title: Re: Flat Air Filter
Post by: nhmaf on August 13, 2010, 08:24:10 PM
??

Have you tried turning it around?

The last filer I bought had some molded area which seemed like it was intended to fit in the space at the front of the airbox/back of the starter area, but it wasn't really the proper shape.   I little bit mof muscle though and It goes in and stays put.

What brand of filter are you using?
Title: Re: Flat Air Filter
Post by: stockman on August 13, 2010, 08:54:53 PM
I read in a manual to apply a light coat of wheel bearing grease around the edges to prevent leaks-- so I did.
Title: Re: Flat Air Filter
Post by: Bob_Roller on August 13, 2010, 09:32:32 PM
Quote
??

Have you tried turning it around?

The last filer I bought had some molded area which seemed like it was intended to fit in the space at the front of the airbox/back of the starter area, but it wasn't really the proper shape.   I little bit mof muscle though and It goes in and stays put.

What brand of filter are you using?

I'm using the OEM filter, it only goes on one way .

There's a service bulletin on it, it's in one of the threads a few weeks about ago about service bulletins .

The filter fits it just doesn't go down all the way, there's about an eighth inch or so gap between the filter body and the air box .

Here's the service bulletin .

https://www.bmwmc.net/catalog/13%20015%2087%20%282245%29.pdf

Just installed a new filter on the '82 LS and had to trim off some of the plastic, contrary to the statement in the service bulletin that after 1986 the filters are the correct size .
Title: Re: Flat Air Filter
Post by: nhmaf on August 13, 2010, 10:30:38 PM
Hmm, intersting.

Maybe the last filters I bought were NOS, I don't have any gaps and they fit very firmly into the air box opening.
Title: Re: Flat Air Filter
Post by: Crossrodes on August 13, 2010, 11:26:54 PM
Does this mean that my '79 has something better than the later model R65's?

YAHOO!

 ;)
Title: Re: Flat Air Filter
Post by: mimmo66 on August 14, 2010, 12:38:45 AM
My 82 R65LS has never had any trim job on the aitr filter, although she would't mind a Brasilian Cut!
Title: Re: Flat Air Filter
Post by: montmil on August 14, 2010, 07:57:19 AM
Quote
My 82 R65LS has never had any trim job on the aitr filter, although she would't mind a Brasilian Cut!

...on the pillion? [smiley=laugh.gif]

Both the filters for my 1981 and 1983 R65s fit just fine, thank you very much. Both have stock, unmodified top filter covers and the aftermarket filters I run fit perfectly.

I'm going to make a SWAG that there may have been a design error from more than one manufacturer of the OEM top cover bits...?

Monte
Title: Re: Flat Air Filter
Post by: Bob_Roller on August 14, 2010, 08:07:18 AM
I'm wondering if there were differences with the air box casting itself, the small 'loops' cast into the box for the spring clips being an eighth inch off or so .

All three of my R65's need to have the filter frame cut out for the filter to fit onto the air box correctly .

The last two filters I got were ordered from BMW, as the dealer doesn't stock them, so I don't think it's an old parts problem in my case .
Title: Re: Flat Air Filter
Post by: Barry on August 14, 2010, 09:31:26 AM
Quote
Does this mean that my '79 has something better than the later model R65's?
 

Well the 79 filter cover certainly looks better, like it was meant to be and the round type filter is much cheaper.  
 




Title: Re: Flat Air Filter
Post by: Ed Miller on August 14, 2010, 05:35:26 PM
I've never trimmed an air filter, and they all fit fine.  6385572 for my VIN.

Title: Re: Flat Air Filter
Post by: Bob_Roller on August 14, 2010, 07:21:43 PM
I've had to trim down every filter including the original that came with the bike when I took delivery of it in '81 .
Title: Re: Flat Air Filter
Post by: bruce_launceston on August 15, 2010, 02:48:04 AM
I've never had any issues with the air filters on the '84 LS, they have always been OEM filters.
Title: Re: Flat Air Filter
Post by: Bob_Roller on August 15, 2010, 08:09:15 AM
The installation looks good, fits like it should, but the filter is held up and not seating correctly on the lower airbox .

Next time you have the filter out check for clearance on the loops that are cast into the lower airbox, the filter frame is usually contacting there .

I cut out about 5 mm or so in the area around where the 'loops' on the lower airbox would mate up to, and the filter then drops down to where the rubber gasket of the filter is in solid contact with the lower airbox .