Quick Thermostat Question

[Sable]

Well we finally had a day without rain here and I completely drained the coolant system on the V and took out the thermostat.

I am still learning about this bike, and I need someone to confirm for me what the thermostat looks like when it is "open". The Haynes manual says that if you pull the thermostat out and it is open, then it is bad. I dropped the thermostat into boiling water and it did expand, does this mean that when it expands that it is open? If so, then I don't need to replace it :o

Again, I have limited mechanical knowledge about this bike and I am tackling problems as they come.... I have fairly good knowledge about the carbs (Thanks Lucky), and the wiring system. Now, I am working on the cooling system and as always any help is appreciated!

~Sable

[Lucky]

if it opens right up it's good.

[jasonm.]

Turn the screw in the middle clockwise if you want the bike to run cooler.

[Sable]

OK... completely flushed the cooling system in the bike on Friday, replaced the thermo housing o-ring. Also did all the tests for the temp. gauge and the thermostat sending unit.

With a bucket of water, at 150 deg. I put the thermo sending unit in with the gound lead on the housing and the positive lead on the wire connector. Put it in the water... and big surprise, no reading! Accidentally knocked the whole thing into the bucket, now I have a reading... I assumed by this, that because there was no reading with the positive lead out of the water that the thermo sending unit is bad. With water being a conductor, when the whole thing was submersed (*sp) it gave a reading.

Went to Yamaha Dealership to get a replacement thermo sending unit.... I was told the bargan price for it was $93.06 >:(
Needless to say, I didn't order one. Talked with the parts guy, who bought a new Vision back in '83 (and wished he never sold it), said he didn't know of a generic thermo sending unit that could be substituted.
New questions:

1) Anyone know of a substitute thermo sending unit that can be used on the V? If so, where can I get one from and approx. cost?

2) If there is no replacement thermo sending unit available, can someone e-mail me a KIS/S (Keep It Simple/Stupid) wiring diagram and instructions so I can put in a toggle switch for my fan.... it's not coming on when the temp gauge gets to about 1/2.

All help is appreciated,

? ? ? ? ? ?~Sable

[jasonm.]

There are 2 sensors in the cooling system. One controls the gauge. The other controls the fan.  You did not say your sener to the  fan  was damaged...did I read wrong? Also, these gauge senders only go bad if you hit them with a tool. "Been there done that." Also next time just use a meat thermometer, $2 @walmart. I'll look for a spare sensor. But you need to be sure which one it is. I believe one has a single wire(temp). The other has at least 2 for the fan to be swithed on. My Vision's fan does not turn on tilll the gauge reads well past the middle.

[Sable]

Jason,
     I'm sure it's the sending unit to the thermostat, not the one to the temp. gauge (the temp. gauge works fine). If you look at the T-fitting for the cooling system, the bleeder bolt is on the top, then on the left side (from the seated position) the top sensor is the thermostat sending unt (the one that is bad), and then below that, is the sending unit for the temp. gauge. Both sensors only have one wire connected to them. I tested it in water with a thermometer (did get it from Wal-Mart).
     I figured that untill I can get another sensor, the best way to put in a toggle switch for the fan was to take the wire from the thermostat sending unit, connect it to a toggle switch, then gound the other end. This will cause the fan to come on when the switch is flipped.  Just like the test in the haynes manual for the fan relay.

~John

[jasonm.]

I just looked. I only have one good one. The other has the wire tab broken off. It may have been hit too. I suggest you double check your thermo-switch. They are not suppose to turn on till about 210. Which is well past center on most V's. I suggest you check it in some near boiling water. And get a $2 meat thermometer.