ok to ride triz w/o thermostat?

[triz25o]

I am curious if you can remove the thermostat from the housing and still ride without causeing any damage also will the over heat light still work?

[twgranger]

I have had people tell me that they run them with out it with no problems.

[chris200x]

Isn't it basically the same as in a car? You only really need it in cold winter months?

[Wickedfinger]

Yes ........ not really needed. Winter or summer, it will take it a bit longer to warm up.

[Darius1502]

I took mine out...runs fine and yes it still warms up just fine. The thmostat is designed to stay closed when cold then open up when hot. This helps the motor reach correct operating temperature faster.

I can tell you that Z's run hotter than R's (in my opinion) so they will reach the correct operating temp quickly without the thermostat.

[Yamahammer490]

I've run mine without the thermostat for two years now, both winter and summer.

[J.D.]

I recommend leaving it in. Yamaha didn't just say "Hey, let's throw a thermostat in!!" It's there for a reason. Contrary to popular belief, a thermostat will actually in most cases help you stay cooler. WTF you say?? Well, here's how. How/What does a radiator do? It allows heat transferred from the cylinder/head to be passed through liquid into the radiator. It needs to stay there long enough to cool back down, so it can go back to the cylinder/head to do it's job again. Here's where the thermostat kicks in: It restricts the flow of water so it stays in the radiator longer before it goes back through the cyl/head. If there is no thermostat, the water will be constantly flying through the radiator and not given a chance to cool down.

Anyways, to the original question....I ran my Z without a thermostat for a long time, even in 110-120 degree desert days riding for hours with no problems.

[Darius1502]

SSJ3Goku, interesting point. I guess when its open it still will slow the flow down some. Did yours ever overheat?

By the way...the fuel pump works great...thanks man!

[OldSchoolin86]

Run with out it, it will cool down just fine.

[Red Rider]

How/What does a radiator do? It allows heat transferred from the cylinder/head to be passed through liquid into the radiator. It needs to stay there long enough to cool back down, so it can go back to the cylinder/head to do it's job again. Here's where the thermostat kicks in: It restricts the flow of water so it stays in the radiator longer before it goes back through the cyl/head. If there is no thermostat, the water will be constantly flying through the radiator and not given a chance to cool down.

Goku, I understand your viewpoint & you're logic, but the purpose of a thermostat, as has already been stated, is to help the engine reach it's proper operating temperature quickly. The point you're missing is this: while the coolant trapped in the radiators is getting nice & cool, the coolant that's trapped in the cylinder is getting nice & hot, thus causing the cylinder & piston to expand at equal rates.

If you fire up your non-thermostat-equipped Tri-Z, and go ripping around in 40 F temperatures, you run the risk of a cold seizure. A cold seizure, if I remember correctly, is where the piston expands rapidly due to heat, but the cylinder doesn't, because it's still cold. So, basically you're forcing a larger-than-usual piston through a smaller-than-usual cylinder, and I think we all know what's going to result from that. A thermostat would have restricted coolant flow until the coolant, and therefore cylinder, was hot enough to cause the thermostat to open gradually. As long as you let your bike warm up for about 4-5 minutes before riding it hard, your thermostatless Tri-Z should do just fine.

[TimSr]

Without the thermostat, you might be prone to fouling plugs during warmup if you dont warm it up properly. In super cold weather, it takes a lot longer to reach operating temp, but once it reaches it, it will stay there and run fine until you shut it off, and it begins cooling down again. They run super rich while they are cold. Only once has it been a problem in Ohio winters, and that was when I was racing Indoor MX, and it was about 15 degrees outside where I had to keep it until race time. The 2 or 3 minutes of warmup time before going inside, and then sitting another 5 minutes shut off before starting the races made it tough to reach operating temp. It took a couple laps before it warmed up enough to get rid of the off-idle bog you get when you turn the choke off too early. Other than that, Ive never had a problem in 14 or 15 years. Keep in mind, I think the Z is the only one that even uses a thermostat. They commonly fail and stick open, so most people that have them dont realize its not doing anything for them. The other plus to not running one is you can pull off your radiator cap and know if your coolant pump is working without having to guess if its warm enough for the thermo to be open.
Unless you run in very cold conditions most of the time, Id remove it, as it just one more thing to malfunction to make diagnosis of cooling problems more difficult.