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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => The Motobrick Workshop => Topic started by: jonnyTHUNDERmaker on June 23, 2012, 03:28:41 PM
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Hello Gentleman,
I am new to the forum and a fairly new BMW K75 owner (love it)
I was having an overheating problem and traced it to the radiator fan motor wiring harness
Good news is I found the problem, better news is the fan motor is still good. Bad news is that that actual magnetic slides that touch the copper cylinder is where the problem was.
Now if I can just track down the actual wiring harness part of the fan motor that would be excellent.
This is what I need. Just the harness. Not the whole motor
(http://i1124.photobucket.com/albums/l572/adriannarnold/92%20BMW%20K75S/7bf45442.jpg)
Actually, this is all I need. Just this one little dang piece. From the brown wire to the copper coil and plastic housing.
(http://i1124.photobucket.com/albums/l572/adriannarnold/92%20BMW%20K75S/f85f5ff3.jpg)
I would rather not have to spend $70 and get the whole fan assembly
Thanks for your help
Here is the link to my thread from DoTheTon. Has all the info on stuff I have done to the bike so far
http://www.dotheton.com/forum/index.php?topic=37865.0 (http://www.dotheton.com/forum/index.php?topic=37865.0)
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I'm not sure if you can buy the harness as such. I'd just buy the fan motor from beemerboneyard or somewhere else who sells it.
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Yeah. I know beemerboneyard has the motor, but it's $70. My hope is to find someone that replaced their bad motor and obtain the part I need from them for cheap.
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Welcome Jonny,
I suggest you check out Duck's (Frankenduck) parts site here: http://www.kbikeparts.com/ (http://www.kbikeparts.com/)
If you don't see what you need, email him. His email is on the first page of the site.
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Thanks Wayne,
Ill look into that
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The motor isn't very different from lots of other Bosch motors used for automotive ventilation fans or radiators. Even though the whole motor is fairly specfic to the brick's application the brush assembly may be common to various Bosch motors. You may want to check with an automotive motor shop, or if you have a good wrecking yard see if you can find a similar motor in a Volvo, VW, BMW, Mercedes, etc.
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First question is what leads you to believe this part is the failing component? Have you tested continuity from the soldering lug to the brush and found it to be open-circuit?
If so, have you thought about trying to remelt the solder on the lug? Or maybe replace the wire from the lug to the brush?
Lots of questions but maybe trying to salvage the assembly you have may avoid having to purchase a new fan motor.
You might want to download the "Heat Management" document from the downloads page on K100rtforum.com as it contains instructions on replacing the BMW fan with a modern DC brushless fan (will give you longer term reliability).
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I apologize for my brief and somewhat vague description. I did multiple tests with the fan and after careful examination I noticed the problem. The brush from the hot lead was severely melted, damaged, crooked, and in no way able to make contact with the actual motor. If you look closely at my second picture above (sorry its blurry) you can tell how disfigured the housing is from the meltdown.
Here is the good side. I noticed the silver clip and how centered the small copper coil and housing are.
(http://i1124.photobucket.com/albums/l572/adriannarnold/92%20BMW%20K75S/28985bab.jpg)
Here is the bad side. No silver clip, I have no idea how that disappeared and how crooked and melted the housing is
(http://i1124.photobucket.com/albums/l572/adriannarnold/92%20BMW%20K75S/29befc45.jpg)
Also the brush looked as if it was resting against the actual motor housing which would have caused the initial meltdown.
I may just go ahead and order the fan motor from beemer boneyard and have a spare. I really want to get back on the K75.
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Take a look in the alternate parts sticky in the lieberry. The motors are an ac condenser fan motor from a few older cars. should be availiable at Napa or whatever car place. or rockauto.com
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wmax,
Thanks a bunch. I will check it out. I was just at Napa a few hrs ago picking up my submersible fuel line.
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Try EME http://www.euromotoelectrics.com/BMW-Motor-Radiator-Fan-K-models-1983-1995-p/fan-k427m.htm (http://www.euromotoelectrics.com/BMW-Motor-Radiator-Fan-K-models-1983-1995-p/fan-k427m.htm)
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Gentleman,
Thank you all for your input. I appreciate it.
I think I have found my solution. I am heavily leaning towards replacing the entire fan assembly with a modern fan (Thanks rbm) I signed up on the K100rt and found the heat management info.
Looks like I can find a 7.5" Spal fan assembly for as much as just the OEM motor (around $70)
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I've looked at those Spal fans before. Let us know how it works out.
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Yeah I would like to know how you go as I get a bit tired of fixing fans over the years.
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Gentleman,
I'll be sure to keep you informed. I just purchased the Spal 6.5" Puller fan from:
http://www.brightonracingproducts.com/65-Spal-Puller-Fan-20-002.htm (http://www.brightonracingproducts.com/65-Spal-Puller-Fan-20-002.htm)
With shipping it was just at $50, so a tad cheaper than just the OEM motor. Should be here is a couple days. Thanks again for all the input.
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Sounds like a good purchase.
My Formula SAE team runs a SPAL fan on the car. Running 22 km in 100 degree heat, the temp never went above 80* C.
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Just curious but why did you order a puller? (OEM is a pusher.)
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I thought it was a puller. It blows air back to my legs when it runs.
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Frankenduck,
I read that it was a puller fan. It pulls cooler air through the radiator. A pusher would push warm air from around the motor into the radiator. I could be mistaken, I guess I will see how it works.
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I was mistaken. When I test them off-bike I usually do it face down and it pushes up (why I was thinking push) when that actually means it's pulling from the radiator.
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Don't worry Duck just keep taking that medication and can I have your bike when they cart you of to the home for the permanently bewildered. :hehehe
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home for the permanently bewildered. :hehehe
I've already been to Australia.
:neener:
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It's not permanent the man in a white coat said I'd get better :loopy:
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Hahaha...Cool, glad that was cleared up. I was starting to second guess. Thanks gents. Hopefully the fan will arrive before the weekend. I cant wait to get back on this thing.
p.s. anyone know a good place to get the hose from inside the tank that goes from the fuel rail return (i believe) to the fuel pump filter spout. I am assuming a 1/4" submersible fuel line would work. A lawn mower shop maybe? I only need like a foot.
p.s.s: Its number 15 on the diagram below
http://www.ascycles.com/Illustrated_catalog2/MicroList.aspx?id=51745&catID=16&catname=Fuel_Supply&bindName=FUEL_PUMP_FUEL_FILTER&bindCat=16_0809 (http://www.ascycles.com/Illustrated_catalog2/MicroList.aspx?id=51745&catID=16&catname=Fuel_Supply&bindName=FUEL_PUMP_FUEL_FILTER&bindCat=16_0809)
Thanks
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Just to confirm, the fan is a puller. I wired my OEM fan up wrong once and experienced constant overheating problems with the engine. It was like a positive feedback loop where warm air in the engine compartment was being forced through the rad, warming up the cooling liquid, ad infinitum. Took me a few months to sort the problem. A real DOH! moment when I solved it.
As for the fuel line, use any hose rated 30r10 for internal to tank useage. Napa and other auto parts stores should carry that and sell it by the foot. This is also useful reading:
http://www.napabeltshose.com/images/Barricade_Training_Final.pdf (http://www.napabeltshose.com/images/Barricade_Training_Final.pdf)
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Ok Gents,
I finally had some time to get the bike back on the road. First the good news.
I tracked some fuel line down locally and got the fuel tank all buttoned up.
New rubber fuel pump damper, new fuel pump filter, and new hoses.
(http://i1124.photobucket.com/albums/l572/adriannarnold/92%20BMW%20K75S/5d14f2a0.jpg)
Then I unwrapped my new Spal 6.5" fan which was packaged nicely.
(http://i1124.photobucket.com/albums/l572/adriannarnold/92%20BMW%20K75S/abc6b307.jpg)
The Spal fan lined up perfectly with the two mounting holes on the bottom. On the top the hole is about an inch off so I fashioned a bracket for it. After all that work when trying to install it I realized the fan housing and the bracket would barely hit the frame (2-3mm). :hmm:
So after some more looking and thinking I removed a small section of the top of the fan housing with a dremel and a part of the top mount. The mount presses up against the frame so there was no need to bolt it on anyways and the fan fit nicely in place.
(http://i1124.photobucket.com/albums/l572/adriannarnold/92%20BMW%20K75S/da9e302f.jpg)
Sorry for the blurry picture, but if you look closely you will see where the top 1/3 of the outside housing has been trimmed back and the top mounting hole is gone.
Next I clipped of the connection that came with the fan and soldered it to the old plug head. Threw everything back on the bike and finally got to take it for a spin after a couple long weeks of waiting.
See next post for the bad news.
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The fan and tank where put on on friday night. I drove the bike about 5 miles back to my place from where I was working on it.
Saturday I got up and drove the bike with my wife on the back about 3 miles, the bike was fairly low on fuel, maybe 1 gallon left in the tank.
Later that afternoon on the return trip we stopped to do pick up some groceries. While cruising around in the parking lot in 100F weather the fan kicked on. :2thumbup: Yay! No more overheating. It blew nice and strong and I could feel the extra air coming at my legs. That was reassuring.
After a quick stop, maybe 30 minutes we hoped back on the bike. Drove through the parking lot and as soon as we got onto the road the bike died. I rolled the throttle and nothing. Electrically it was all still on, but no motor action.
I pushed it into the nearest parking lot to take a look. Like I said low gas, but not out. The first couple times I tried to start it it gurgled for about 1 rotation. After that nothing. I pushed it about 1/4 mile to the gas station and put in another gallon and a half just for the heck of it. No change.
Pulled the plugs, they looked fairly lean. Then I noticed I didn't hear anything coming from the fuel pump. No noise, whine, clicking, nothing.
So did my fuel pump just kick the bucket after I did all that work to prevent it? Did it sitting out of the tank for 2 weeks kill it? At this point I am leaning towards a dead fuel pump. Is there any good ways to test it? Thoughts?
Thanks
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Could also be your connector to the fuel pump, quite common problem.......RHS battery cover.
Also check that you got power at the green/white wire in this connector at harness side, when pushing
the starter button........if not, check fuse #6.
If you got power at the connector, measure if it`s present directly at the fuel pump connector w/o voltage drop.
Inge K.
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Thanks Inge K,
Just did a little testing. I believe I tested the correct locations.
Fuel Pump harness connection. I tested the green/white wire on the bike side of the harness
(http://i1124.photobucket.com/albums/l572/adriannarnold/92%20BMW%20K75S/53491e25.jpg)
I got around 11.4v, I cleaned the connectors with contact cleaner again and got the same.
Next I tested the connection at the fuel pump itself. I unclipped the pump from the tank and pulled it our enough to unscrew the connections. I also got 11.4 at these
(http://i1124.photobucket.com/albums/l572/adriannarnold/92%20BMW%20K75S/4b887d26.jpg)
Next I tested the battery and ground it to the frame it read right around 12.8v
So???? Will the pump not fire at all unless it gets at least 12v? Is a loss of about .6v enough to screw things up? Where should I troubleshoot next? Thanks again
Also I forget to mention, when we stopped to shop the fan was on when I turned off the bike, would this have any affect on draining the electrical system/battery? It doesn't seem likely it did if my battery is now reading 12.8V.
Just trying to think of everything here without giving up and replacing the fuel pump. Is there a safe way to test the pump directly?
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A voltage drop of 1,4 is a bit much.........but the pump should still run I think.
It seems like your pump is the problem.
What I did have in mind when I said "measure directly at the pump" it was just that.......
The idea was to test out the connector.......with no load in the circuit, you won`t reveal this.
You could also test the pump with a pair of wires with the correct connectors as on the fuel pump
and long enough to reach the battery.
Connect to the fuel pump, and other ends in your hands...and just connect at the battery a couple
of seconds at the time..............try both directions.
Much muck in the tank lately?
Is the the gause present at the bottom of the pump?
Inge K.
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Ok, Tested the pump directly.
Ran wires from the battery directly to the pump. It kind of jolted a bit and everytime I touched the battery, but didn't "stay" on.
No muck in the tank at all, but I did remove the float off of the gauge when I went through the tank to clean it. The float is filled with gas and no longer floating. Without the float would this "tell" the system there is no gas and cause the pump not to run?
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The level sensor just signal the warning lamp (and gauge, if fitted) and nothing else.
It seems like something have jammed inside the pump.
Did you try both directions?...........a few did have suucess with this, when the pump been jammed.
Some have opened the fuel pump, and that way prolong the lifetime a bit....
I`ll see if I can find back some links............don`t have to high expectations.........
If I added together all hours I`ve used for searching old posts on the net w/o any success...........
I would be scared to death...........
Inge K.
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Thats what I figured for the gauge.
By both directions, do you mean swapping the connectors on the top? Ill try that. Thanks for helping me out on this
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With both directions.............it`s enough to reverse the wire ends which you hold in your hands
when connecting to the battery.
Inge K.
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Ok tried that,
Nothing except a little jolt. Is it possible that an air bubble got inside and messed stuff up? I replaced the return line that goes into the fuel pump filter inlet and I am sure there was air in it.
Again not sure about any of this as it ran fine for about 10 miles and the stopped suddenly.
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Thanks for helping me out on this.
............see that you are located in Austin.....................and I just loves the blues.........
just kiddin..........would have helped anyway.
Inge K.
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A air bubble would`t make trouble like this, if you got just air inside your pump it would run but not deliver.
The hose attached to the gauze is for ventilation, so it`s quite normal that it got air inside.
That it did stop suddenly don`t seems that strange, since it looks like something been jammed inside.
Inge K.
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Some have opened the fuel pump, and that way prolong the lifetime a bit....
I`ll see if I can find back some links............don`t have to high expectations.........
If I added together all hours I`ve used for searching old posts on the net w/o any success...........
I would be scared to death...........
Then I have to add another hour to my list...........scaring.
And you would be occupied rest of the evening, after you have checked this (http://hrsbstaff.ednet.ns.ca/bvogel/K100/fuel_pump/index.html).
Or the easy path, put in a aftermarket, look in the "Lieberry".
Inge K.
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Thanks Inge K,
Looks like Ill be digging into the fuel pump tomorrow evening to see what I can find.
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Q: how's that Spal holding up? You are the second person I see on the board doing a Spal mod. What did you do for the top fastening, and if it is still working, what would you do differently? Your mod seems to have the advantage of using the less expensive fan, as well as less extensive fabrication.