K11 Owners Group

Flying Duck

This winter I plan to tear down the RS a bit. After the spline lube I'm going to do some 'sperimetin' with the cooling system.

I've got three things to try.

1) I have a 3 core radiator I scored cheap on eBay that someone had already installed a thermoswitch in. It looks something like this and is installed near where the coolant from the head comes in:

Actually, I'm not 100% sure it's a thermoswitch. The one I have doesn't have any numbers on it so it could just be a sensor for all I know. We'll see....

2) I've built one of these and need to test it:

http://autospeed.com/cms/title_Electronic-Radiator-Fan-Switch/A_2477/article.html

3) Lastly, I just found this thermoswitch on eBay that's only $24 shipped. I thing this thing could be the ticket since it's easy to install and cheap to boot. I found several references to it in car forums where guys have had good luck with it installing aftermarket fans in the cars.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=370261292681&viewitem=&sspagename=STRK%3AMEWAX%3AIT

_________________
93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
86 K75C w/paralever, hi perf cams,TURBO!
91 & 92 K75Ss
91 K1
86 custom K100
14 WR250R
IBA #17739 (SS1K, BBG, 50CC)
Buy parts HERE

Mystic Red · Posted: Sat Sep 19, 2009 1:00 pm Post subject:

Be interesting to see how that goes. I'd like mine to turn on a little earlier.
_________________
Scott Hespelt, '94 K11LT
K11 OG #466

Saltcreek · Posted: Sat Sep 19, 2009 1:12 pm Post subject:

Seems a shame you can't just adjust the sensor that's already telling the fan to come on.
_________________
Jim

1994 K1100LT Mystic Red, bfd, 37000 miles, sold Sad

2009 Wilderness Systems Zephyr 155 ST
2002 Litespeed titanium

Flying Duck · Posted: Sat Sep 19, 2009 1:20 pm Post subject:

max · Posted: Sun Sep 20, 2009 6:43 am Post subject:

Duck

Can I also suggest trying something like these:

http://newzealand.rs-online.com/web/search/searchBrowseAction.html?method=searchProducts&searchTerm=to220+thermoswitch&x=0&y=0

About $6US? RS Components are worldwide, or you can search for AirPax at someone like Mouser or DigiKey? NO or NC contacts, temp like 70 / 80 / 90 / 100degC

They're waterproof, gold contacts and can take up to 160degC long term, and do about 38000 cycles of 1A @48v... I know this won't switch the full fan directly, so you'd have to use a relay - but sticking the tab under the mounting screw of something direct on the head/block is a lot easier than tapping & waterproofing a sensor into the coolant stream, and then having to waterproof the switch cage too.

(I'm going to use mine - 90degC - to switch the fan-via-ballast here, that's only just over 1amp anyway, so get no fan until 90deg (on head), ~40% continuously then and for spikes the main full-speed still will kick in.)

Just might be easier, anyway

Max

Flying Duck · Posted: Sun Sep 20, 2009 12:08 pm Post subject:

That's interesting. On one of the car forums I was surfingl I saw a kit that uses something similar - but was adjustable. But that was $115 so I ruled it out.

I actually built two of the kits (#2) above. I bench tested them yesterday and couldn't get either to work. I'm pretty sure I assembled them correctly because I've done kit stuff before and do have a clue what I'm doing.

Besides the circuit board for the kit is large so right now I'm leaning towards the #3 $24 thermoswitch because it's adjustable. That will enable me to fine tune when the fan kicks in. I bought one from Summit on eBay yesterday to experiment with.

The probe doesn't actually penetrate the radiator, it's inserted between the radiator fins. I'll probably put the control unit under the tank and am not concerned about waterproofing it. I looked at the manufacturer specs for it and it has a 15A capacity which is more than enough for the fan.

But when I get to this, I'll test all 3 of the methods I mentioned above and report back.
_________________
93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
86 K75C w/paralever, hi perf cams,TURBO!
91 & 92 K75Ss
91 K1
86 custom K100
14 WR250R
IBA #17739 (SS1K, BBG, 50CC)
Buy parts HERE

hockeyshifter · Posted: Sun Sep 20, 2009 5:54 pm Post subject:

These bike are set up like a car 325i .. just smaller. the "switch on the block " is really only use to manage fuel mix during warm up once the o2 sensor gets it correct reading the mix leans out. once at optimal temp the sensor is really only for the fan.

what needs to happen is a seperate switch in the radiator it self... that is paced in front of the block sensor circut. remember electricty looks for the shortest path. also make sure you put in a relay that is connected to the switch other wise the fan will kick on with out the key in. by placing the seperate fan switch seperate form the block sensor is that you can control it with a switch or with a resistor ( ie dial in the fan speed)
also having this set up will protect the delicate circut boards and programing in the ecu itself . if you get a short you might cause more damage to high cost components than damaging to a simple circut switch ...
_________________
fix the problem not the blame ; fix what is messed up ; NO one is to blame.

Flying Duck · Posted: Sun Sep 20, 2009 6:31 pm Post subject:

My plan is to have the switch trigger a micro relay that grounds the existing fan relay. That relay is switched power already and I won't need to add another fuse.
_________________
93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
86 K75C w/paralever, hi perf cams,TURBO!
91 & 92 K75Ss
91 K1
86 custom K100
14 WR250R
IBA #17739 (SS1K, BBG, 50CC)
Buy parts HERE

Flying Duck · Posted: Sun Sep 27, 2009 10:58 am Post subject:

owrstrich · Posted: Sun Sep 27, 2009 11:04 am Post subject:

arent you in the sand box... what was it 117 there yesterday... good place for fan switch experimentation...

j o
_________________
yeeeeeehaaaaaaa...

Flying Duck · Posted: Sun Sep 27, 2009 11:21 am Post subject:

I arrive in the "sand box" on Wednesday evening. Very Happy

_________________
93 LT (x2)
94 RS
86-97 K75F(K75/100/1100 Frankenbrick)
86 K75C w/paralever, hi perf cams,TURBO!
91 & 92 K75Ss
91 K1
86 custom K100
14 WR250R
IBA #17739 (SS1K, BBG, 50CC)
Buy parts HERE

owrstrich · Posted: Sun Sep 27, 2009 12:02 pm Post subject:

r o d g e r t h a t...

well then... i may pull out the smoker and fill it full of pig ares... or prime ribbs... or both...

j o
_________________
yeeeeeehaaaaaaa...

Flying Duck · Posted: Sun Sep 27, 2009 12:10 pm Post subject:

6899 · Posted: Sat Oct 03, 2009 6:11 am Post subject:

Duck,

What 3 core radiator did you get? A K100? Custom recored K1100?

Just curious. A 3 core rad will cure most problems.

Thx

Bagram Red
_________________
1996 K1100LT, 73K (bought at 61K on 2006)
1977 R100/7, bought new, rode 97K in 29 yrs before parting out
1970 R50/5, bought used, rode 40K & sold

BMWMOA #6899 since 1976
Indy BMW Club since 1975