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Discussion Starter · #1 ·
What's up, everyone! New to the forum, as well as the motorcycle world, so bear with me here.

I just bought a 1978 CX500, and since then it has been running pretty hot according to the gauge. So I purchased a new thermostat (New Thermostat GL1000 1100 1500 Goldwing CX500 CX650 GL500 GL650 | eBay)

When I went to replace it last night, I opened the housing to find that there was not a thermostat in there.

I understand the concept that running without one can keep the bike from overheating for a short period of time, but on the other hand prevents the radiator from fully cooling the coolant down.

I placed the thermostat in spring side down (i think... i distinctly remember putting it in one way and it not closing, then flipping it and it sealeding up no problem) reinstalled everything as it was and now the bike is overheating even faster.

I've read that testing the 7v Regulator is the next step, but I cant find a solid walkthrough on how to do that- does anyone have one? I have a voltmeter, but not a clue how to test the regulator

Another note, when I removed the water pipes and the thermostat housing, a bunch of blue coolant(?) came out of the bike. The coolant in my reservoir is still very very green (and full), so I know it's not pumping back and forth. Could there be a block somewhere causing it to overheat?

Thanks in advance!

Garrett
 

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Just check the voltage on the wire going to the sending unit near the t-stat. It should be very near 7V. There is a bullet connector under the fuel tank on that wire where you can check the voltage.
 

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How hot is it running?

My temp gauge reads about halfway between where the white line goes from thin to thick and the red zone on hot days like when its in the 90s, especially if I'm running it at speed like on the freeway 65-70mph. I'm told this is normal. I'll notice the temp even climbs a bit over half in those conditions if I'm following behind another vehicle and am in the wind shadow of that vehicle (less air mass hitting the radiator). This was the case just yesterday and I was worried something was wrong since I've just been doing a bunch of cooling system work, but then last night when it had cooled into the 80s, the temp needle was closer to that split from thin to thick in the white line.
 

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Discussion Starter · #5 ·
Just check the voltage on the wire going to the sending unit near the t-stat. It should be very near 7V. There is a bullet connector under the fuel tank on that wire where you can check the voltage.

it's reading 7.3 ish
 

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If thermostat is new check for corrosion in the radiator itself. After 36 years they tend to be corroded. If you flush or drain be sure to burp the system to prevent air pockets.
 
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