K75 Cooling Fan?

[cayuse60]

The contnuing tear down of the 1991 K75 I recently bought:rolleyes .

It would seem this is not the OEM electric radiator fan. Can anyone out there identify it?

The only part no. on it is 062500-5990, 12 4 J, MADE IN JAPAN.

tia----tim

[OfficerImpersonator]

I just replaced the radiator and fan on my '92 K75S. Your fan is definitely NOT stock. The OEM fan attaches to the radiator in three places - yours appears to only attach to the radiator at two places. You can see the unused mounting bracket at the bottom right of the radiator in your photo.

I discovered (the hard way) that OEM fans occasionally "drill" into the radiator due to too much play on the fan shaft, allowing the shaft to come into contact with the radiator, causing a leak and requiring both a new fan and a new radiator.

You should be able to find a used OEM fan out there for about $75. I see beemerboneyard.com had one for $78, but they've sold it. I'm sure others posting to this thread will provide links to other online purveyors of used parts.

I got my new used radiator and fan from my independent wrench, who charged me $100 for the radiator and $50 for the fan, and another $150 to install the two. Perhaps your wrench has a supply of used parts he'd be willing to "part" with?

[jdiaz]

Actually, if the bastard fan is working ok, leave it alone! There's nothing special about the BMW fan other than price and availability.

[cayuse60]

Actually, if the bastard fan is working ok, leave it alone! There's nothing special about the BMW fan other than price and availability.


The fan (what ever it is:dunno ) is operable when fired up with 12VDC. The way it was mounted left alot to be desired...a new mountinting bracket and edgeing the shround with split 1/4 in. vacuum hose helped keep the shround from contacting the radiator cor. The orinal picture only shows the one bolt holding the whole assembly in place allowing the fan shround to vibrate against the radiator core.:uhoh
I removed the motor and fan and have fitted the pictured configuration to the clearances behind the fan motor and above the engine and no more contact between the fan shroud and the core.

I'll let you know how this works, but still would like to know what I have for a radiator fan.

----tim

[98lee]

, but still would like to know what I have for a radiator fan.

----tim



It's either for a 1958 Borgward Isabella TS or a 2006 Aston Martin DB9.:bottle

Either way, it should be more than enough unless the bike is orange.


Sorry, I couldn't resist.:stick


:dance :dance :dance

[cayuse60]

It's either for a 1958 Borgward Isabella TS or a 2006 Aston Martin DB9.:bottle

Either way, it should be more than enough unless the bike is orange.


Sorry, I couldn't resist.:stick


:dance :dance :dance

Thanks...it will remain a mystery, or as has been stated in an earlier post...bastard fan:beer

[deilenberger]

It's not an Isabella one.. they were made in Yugoslavia.

Whatever it is - it's probably BETTER than the POS BMW put in at the factory... that has a habit of seizing up and burning up.

If you can come up with a clean mounting - I'd suggest browsing JCWhitney&Co website and see if you can figure out what it is - you'd have a marketable replacement for the horribly expensive and generally awful BMW OEM one.

[deancox]

[QUOTE=dvandkq;199805] I see beemerboneyard.com had one for $78, but they've sold it. I'm sure others posting to this thread will provide links to other online purveyors of used parts.
QUOTE]

I bought that fan from BBY a couple weeks back and have it installed on my '89 K75C. It just saw me through my first IBA qaulification ride...so far so good, but I would have preferred a new one, but doubling up on the $78 (more or less) was against my religion.

I understand the Bosch motors are/were used on early Porsche 911 airconditioning condensor fans, but I could never suss out the correct part number although there a list on another board that claims to have it...I couldn't verify it.

I took my fan motor to a local rebuilder and he said not to bother. I am a little nervous to have a used fan on the bike, and I would certainly be willing to use a "bastard" fan from another application if I knew exactly how to spec the replacement out. I am sure I could fabricate a mounting.

Anyway, my bike has an operational fan for the first time in the 3 years I have owned it. Whenever the cooling light came on in the past, I just began splitting lanes or pulled over and shut it down until I could move fast enough to get air flowing.

Bottom line, there has to be a better answer than what BMW provides. It seems as if the design is very vulnerable to road grit, water, and the elements in general.

[98lee]

Dean,

Check out euromotoelectrics.com.:german

They have just about any Bosch part available for K and R bikes. Complete fan assemblies $120, fan motor only $69.

They also carry fuel pumps $139 & $219. They carry starters and alternators, plus they carry all the rebuild kits ( brushes, stator kits, drives, regulators) if you feel like rebuilding your own stuff. Also complete Bosch line of plugs and coils and filters.

The owner, John, is a fellow Beemer rider in Colorado who, through his connections in Europe from working at Lucas Electrics (go figure) and Bosch, decided there was a need to make this stuff available without the crazy markup. He has researched over 150 Bosch parts for our bikes and is a pleasure to do business with. Try giving him a call.

I made the decision last year that I didn't want to trust 20 year old fuel pumps or fan motors on my bikes, especially now that my wife is riding one of them.:heart

:dance :dance :dance

[deancox]

Lee: Thanks! With an '89...I have the same concerns,,,,except my wife does not ride, so my concerns are more selfish....I just don't want to be bummed out on the side of the road.

[cayuse60]

Bastard radiator cooling fan appropriately installed.:)

[jimmyenglish]

So what is the bastard fan model #? I need one too and there's no way I'm going to pay oem prices for something that almost never gets used. Thanks!

[BuddingGeezer]

I have had to replace the fans in 1987 K75 & K100. The K75 I bought a Beemer Boneyard used fan and the K100 I bought a new Bosh motor and rebuilt the fan.

If you have a good working aftermarket fan, don't mess with it. The Bosch fan motors tend to melt the plastic brush holder. This is the same motor used in early Porsche 911 air conditioner condensers. They also melted the plastic brush holder.

Not a good design.

Ralph Sims

[BuddingGeezer]

[QUOTE=deancox;200264][QUOTE=dvandkq;199805]

I understand the Bosch motors are/were used on early Porsche 911 airconditioning condensor fans, but I could never suss out the correct part number although there a list on another board that claims to have it...I couldn't verify it.



I called a foreign car parts store with the proper part number. They can't get it. Must be a dealer only item. I paid less than $70 for the new motor at Beemer Boneyard. The BB fan motor has spade terminals. My wires would not fit in the motor case with spades. I soldered directly.

Ralph Sims

[98lee]

Once again: euromotoelectrics.com

More Page
Part Name Motor Radiator Fan - K models 1983-1995
EME Part Number FAN-K427M
Product Description Bosch Original Equipment New MOTOR; Fits ALL K models 1983-1995. This is the motor only. Some careful dis-assembly of the orignal radiator fan assembly required.
Vehicle Manufacturer Name BMW K
Vehicle Manufacturer Part # 1 74 01460 427, 51 33 1 460 427
Manufacturer Name K
Vehicle Model # K75, K100, K1100
Engine Displacement 750cc, 1000cc
Vehicle Model Start Year 1983
Vehicle Model End Year 1995
Application BMW K75, K100RS,RT, LT, K1100
Assembly Name Motor for Radiator Fan Assembly
Original Equipment Manufacturer
Unit Manufacturer Name BOSCH
Power Rating 12 V, 28 Watts, 4 Amp
Technical Specification 4500 RPM nominal speed, 6 Ncm Continuous Torque, 35 Ncm Breakaway Torque. Spade terminals allow easy reconnection of original wire harness coupling.
Retail Price $69.00
In Stock
Availailable
Picture
Drawing Picture

[98lee]

OR:

More Page
Part Name Radiator Fan Motor Assembly - K models 1983-1995
EME Part Number FAN-K427
Product Description Bosch Original Equipment New Fan Motor Assembly. Fits ALL K models 1983-1995. Complete motor, fan and housing assembly. BMW # 1 74 01 460 427, 51 33 1 460 427 . For MOTOR ONLY, see Pt # FAN-K427M.
Vehicle Manufacturer Name K
Vehicle Manufacturer Part # 1 74 01460 427, 51 33 1 460 427
Manufacturer Name BMW
Vehicle Model # K75, K100, K1100
Engine Displacement 750cc, 1000cc, 1100cc
Vehicle Model Start Year 1983
Vehicle Model End Year 1995
Application BMW K75, K100RS,RT, LT, etc
Assembly Name Radiator Fan Motor Assembly
Original Equipment Manufacturer
Unit Manufacturer Name BOSCH
Power Rating 12 V, 28 Watts, 4 Amp
Technical Specification OEM Fan Motor with fan and housing. Improved heat resistance provides longer life when exposed to high heat in the K application.
Retail Price $120.00
In Stock
Availailable





:dance :dance :dance

[warredon]

Lee, thanks for posting. I'm sure I will use him in the future.

[jimmyenglish]

Yes! Thanks for all the good info!

[soccerchainsaw]

My recently purchased '85 K100RT started buzzing in a funny way at the end of a recent ride. I suspected either fuel pump or fan issue (no change in sound whether stopped or riding). When I opened the fuel cap there was no noticable change in sound (with about 2/3 tank of gas). After reading this thread I'm thinking more about the fan.

Please feel free to comment cause I'm really open to suggestion and I hate taking any motor vehicle to a shop without already having a good idea of what is wrong!

[BuddingGeezer]

My recently purchased '85 K100RT started buzzing in a funny way at the end of a recent ride. I suspected either fuel pump or fan issue (no change in sound whether stopped or riding). When I opened the fuel cap there was no noticable change in sound (with about 2/3 tank of gas). After reading this thread I'm thinking more about the fan.

Please feel free to comment cause I'm really open to suggestion and I hate taking any motor vehicle to a shop without already having a good idea of what is wrong!

If the fan is running, there is no mistaking the sound of the air its pulling through the radiator. You can not hear the motor, it's the air being moved that makes the sound.

The fan doesn't run until the engine is very hot. If the bike is moving above 10 mph the fan shouldn't run.

If you hear a buzzing sound when the bike is moving, I doubt it's your fan.

The Clymer repair manual fan test is wrong.
On the L Jetronic K bikes, you can ground the temp probe (one lead goes to the fuel injection control and the other to the fan switch, you may have to try both in the plug) and hit the starter button. If the fan, fan switch, are all good the fan will run.

Ralph Sims

[mrich12000]

thanks for the fan info I save the post to a word format and saved in my K75 folder,great thanks. :thumb

[soccerchainsaw]

My buzzing started after a ride in the area to get things warmed up, etc. I had been noodling around town and it started after puttering into my neighborhood. In other words slow speeds & not much wind movement. After shutting down for a little while, I started up and the buzzing started up as well. (I doubt things had cooled down much.) I haven't been on a ride since to see if it starts up right away. My prior riding had been from Phoenix to Charlotte in February so with the cooler temps and highway speeds, this fan may not have been on at all.

Thanks for everyone's input.

[bikerfish1100]

buzzing sound, or buzzing vibrations? if sound, consider it might be sound of fuel pump when low on fuel (1 gal or less remaining)