Go Back   ADVrider > Bikes > Thumpers
User Name
Register Inmates Photos Site Rules Search Today's Posts Mark Forums Read

Thread Tools Search this Thread Display Modes
Old 04-02-2008, 07:16 PM   #1
reepicheep OP
Gnarly Adventurer
Joined: Sep 2006
Location: Lebanon, Ohio
Oddometer: 232
KLR 250 temp sensor kludge... sticking it to the man!

Well, after 20 years, the temperature sensor switch for the fan died. The previous owner had wired a manual switch in place of it, but it bugged me that its not automatic, and was yet another thing to confuse some poor newbe if I loaned the bike out to them (which was one of the main reasons I got a KLR-250 in the first place).

So I started hunting. Sure, I could have bought the $50 Kawasaki part, which I am sure my dealer doesn't stock, but where is the fun in that?

The solution? Go to Autozone, and ask for a coolant fan switch for a 1991 Honda Civic. It is part TU121, and will be about $13.99. They will probably have it in stock.

Get a die, Metric 10mm by 1.25. You need to cut new coarse threads. You will need an o-ring as well.

Then just cut the new threads, and slap it in! The original switch is probably a bimetal switch, so it goes from infinity to zero ohms at a particular temperature (with hysterisis). This part is a resistor that changes with temperature. But hondas have relays as well, just like the KLR does, so the Honda part will turn on and off the KLR relay just fine.

This was actually the final result that worked, not the intermediate tests and hunting. You have no idea how hard it was to find the right "non standard" part. I probably spent $70 in gas and on parts before I found the $14 part that was the right one... so other people have to use this so I can pretend it was worth it

That thing with the "97M" on the side is the original part (gutted). The new shiny one is the Honda part, and the box shows the part number.

Enjoy! I hope this is useful to somebody! I tried it a few times tonight, and it worked fine. When my temp guage got just a shade past half way, the fan kicked on and ran for a few minutes.

This will probably work fine for other water cooled bikes that have a temperature sensor that runs a relay that runs an electric fan...
reepicheep is offline   Reply With Quote
Old 04-03-2008, 06:26 AM   #2
tbirdsp's Avatar
Joined: Mar 2002
Location: Nebraska
Oddometer: 8,774
Funny, I had a Mojave ATV (same motor as KLR250) and the fan switch was bad in it too. I put a manual switch in

Good job on the penny tech fix that cost 90 bucks
Mike S.
'09 Bonneville Black, '05 KLR650, '07 Yam Majesty
tbirdsp is offline   Reply With Quote
Old 04-03-2008, 09:36 AM   #3
reepicheep OP
Gnarly Adventurer
Joined: Sep 2006
Location: Lebanon, Ohio
Oddometer: 232
The story of my life! All in all it's cheap entertainment though... when I was fixing this, I was too busy to break other stuff :)
reepicheep is offline   Reply With Quote
Old 05-10-2013, 12:13 PM   #4
Time to ride....
evilwerkz's Avatar
Joined: Nov 2009
Location: Taxco, Mexico......
Oddometer: 205
I tried this and would like to report that IT DID NOT WORK for me, the TU121 is too cold, turns the fan on before the KLR250 even gets warm, and it does not let it turn off its a no go, at least on my 2002 KLR 250
evilwerkz is offline   Reply With Quote
Old 05-10-2013, 02:53 PM   #5
Gnarly Adventurer
Joined: Aug 2010
Location: northern n.y.
Oddometer: 278
You are a gentleman and a scholar, thanks for the tip, stop by spot c15 at mid ohio for a free beer and abuse, emti
emti is offline   Reply With Quote


Thread Tools Search this Thread
Search this Thread:

Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump

Times are GMT -7.   It's 04:33 AM.

Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2015, Jelsoft Enterprises Ltd.
Copyright ADVrider 2011-2015