'82 Thermo switch found

[vl5150]

If your bike runs fine, then great.  For those of you that need help, then please read on.  There's multiple posts of people running fan switches so this is an alternative and I decided to try something different to solve this once and for all.

My bike runs into the red when stuck in traffic because the fan does not turn on until after the needle is almost to the red line.  I live in S. FL and the temps have been over 95 F so this has been happening a lot.  The blue coolant from the bike shop works good, but just delays the needle from spiking  .  I recommend a flush of the system with distilled water and refilling with quality coolant.  So for my bike this is what solved the problem (instructions below). On my bike the fan turns on now just above the middle of the temp gauge and turns off just below the middle of the temp gauge.  Problem solved in 20 mins.

I put in the 170 degree thermostat, PN W0133-1634599
I then ordered  a Duralast SW1799 thermo switch from auto zone.  Don't freak out when you see it.  It works and has specs to keep you running at  ~180F in traffic instead of ~215F
I went to Ace HW and got some wire and connectors (pictured and listed below).


Do this at your risk!
remove the tank, airbox, etc to get to the sensor housing.
Leave the old thermo switch in.   Unplug the battery negative terminal. Make sure bile is cool.
It looks like the hole where the stock switch goes uses a tapered thread so the new sensor doesn't really go in there.  It does fit perfectly in the regular 10mx1.0 thread where the "burp" bolt goes.
Take the "burp" bolt from the top of the aluminium sensor housing. 
I used teflon tape. Put the new switch in..
Take the connector from the stock thermo sensor and put it on one of the terminals of the new thermo sensor.
Make a short wire for the ground using a Noble 522M and a Noble 223M connector as pictured.
Hook the connector to the other switch connector and the other ring connector to share the ground on the housing with the existing wire.
Remember leave in the old switch in.  It's unused and needed to plug the hole.

Put it all back together and post your feedback here to see how this is working for you.  Nothing permanent so it can go back to stock if you like running hot.

I just ran it for an hour and let it idle for 20 mins.  No problems so far, but YMMV.

[vl5150]

Another pic..
This pic doesn't show it well but the stock ground is screwed into the housing along with my wire. If you don't have the stock ground screwed in your temp sensor and display won't work.

[Rikugun]

Thanks for the detailed write-up. Looks to be a straight forward installation some members may find helpful.

Just to clarify a couple of things...

As of this post it's only the hour test ride followed by 20 minute idle period? Was this in the 95 degree weather that had been giving you trouble? As you get more miles with the new switch let us know your findings.

I'm a little confused about the new switch threads - do you know if they are tapered or not? The burp hole threads are parallel and the bolt has a flange to tighten and seal against. Tapered threads use a wedging effect to tighten and often a sealant.

Tapered vs. parallel aside, are the old and new switches different diameter thread i.e. 8 vs. 10?

[vl5150]

Yes, I'm asking for more testers to try it out.  I rode it in the same conditions that would have cooked the engine before, including let it sit for 20 mins.  On my bike, when the fan kicks on, the temp goes no higher.  this was the case before, but the old thermo switch waited until the red line to do it. No I never actually over heated, but it was darn uncomfortable being that hot.  My my experience with the Corvette, the engineers ran them hot for emissions purposes and this may have been why Yamaha spec'd the fan to come on at 210C.  I reprogrammed my vette's fans to come on lower and picked up a few .10's in the 1/4 mile (along with ditching the 190f thermostat)

As for my mounting location, you certainly can try to get it into the stock hole.  I went to the hardware store with the old sensor and it came up as M10X1.0 thread and the new one is the same, but I couldn't get mine to thread in the stock location.  I didn't want to to damage the housing so I used the upper position.  Someone else should try and report back.  It looks like there should be no size issues getting it into the stock hole.

There's plenty of other switches that are M10x1.0, but the temp on/off settings aren't published.  This one was and I didn't want to spend $20 a pop boiling water in an pot and testing the circuit's of the others.

The new switch is teflon taped and screwed in all the way to the aluminium housing.  I haven't seen any leaks so far.

If your cooling system is serviced and the fan works good enough to keep the temp from rising further this should work since the fan kicks on at 185F and turns off at 176f.  If your fan kicks on and the temp keeps rising, then this will not work for you and there's another problem in the system resulting in the fan being ineffective.  These bikes are over 30 years old so lots of variances amongst us at this point.  I have a few older Corvettes and no 2 are alike either and develop individual personalities.

Here's a list of the switches:
http://www.thirdgen.org/techboard/cooling/648953-list-fan-switched-pns.html

[Rikugun]

OK, thanks for the additional info - that's odd it wouldn't start in the stock position. From the picture it appears to have parallel threads so maybe that's why. I wonder if in it's intended application it utilizes a 10 mm crush washer. In any event, it tightens down until it's shoulder seals against the aluminum fitting?

My experience has been similar in hot weather. When the fan (finally) comes on it won't necessarily lower the gage but does keep it from climbing higher. Not much wiggle room at that point and my gaze frequents the gage rather than the road ahead.  :(  Seems reasonable to arrest it's progress before allowing it to flirt with the red zone.

[vl5150]

I was going to do another round of testing today, but my bike won't start since the starter innards looks like the Exxon Valdez oil spill. 

So a starter rebuild kit on order and a week down  >:(

[sunburnedaz]

I went and looked at the joint today where all the sensors and bleed screws are. I think both the sensors are threaded to JIS tapered metric threads. AKA good luck ever finding them.

And the burp screw is threaded for 10x1.25 standard thread which relies on the gasket at the top for sealing, hence why the new sensor fits there as anything with parallel threads can not use the threads alone for sealing.

[vl5150]

So far so good with mine.  No leaks. I did wrap the sensor with teflon tape.  Plumbers putty would probably work fine too.