Thermostat.

Mad Frosty wrote:

Pathfinder wrote:Just to clear one thing up about EVANS.....your engine will actually run hotter than with ethylene glycol/water mixes
A lot of people get confused and think EVANS cools better, It doesn't, it simply tolerates a higher temperature without boiling off. so if the slightly higher temp is ok for your engine, then its safer to use

Correct .

Umm, yay & nay. Yeah, it definitely will run hotter, but what does Pf mean with "slightly hotter"? Besides, what about marginal situations, tight slow singletracking with little wind through the rads? The temp will soar but the rider will be blissfully unaware of it because the stuff does not boil off... which ain't good for the engine!
Water please, with some glycol added >> called coolant, sold the world over! Cools best, protects so well it is OEM-prescribed by all manufacturers bar none, and is cheap enough too.

Hi guys. I found my bike was running quite cold on its first ride when I bought it. It was a fairly warm day. I expected it to hit high 70's C but it never got there. I pulled the thermostat out today and found the pin bent. A common problem from what I read. I pushed it straight and it ran home smoothly as it should. I figured the only problem is the height of the upper cage. It's too high. The pin can extend too far and run out of it's "guide" and cock to the side. When the thermostat is closed (cold) it still has quite a bit of pin exposed which is wasted travel. Around 3 mm I reckon. I didn't measure it. I put it in the vice and crushed the entire housing to bring the gap back to 0 mm. I then put the lower housing back in the vise and squashed it back a bit to give the pin a tiny amount of exposure. Around half a mm. I put it in a pot and cooked it slowly with a thermometer in with it. I did two runs. It opened both times at 80 degress C which is perfect. It slowly opened wide open as the water heated further. As the water reduced in temp the valve was still open at 80 C and didn't close completely til it got down to 75 C. That's a perfect hysteresis in my book. The Honda thermo may be perfect apart from having insufficient travel of it's guide pin. That's all that pin is there for, to guide the thermo open and closed again. Since the cage is too high, you can lower it mechanically in the vice. Rudimentary I know, but it seams to have worked perfectly. I'll run it a while and let you guys know how I go. I'll know, because the days are hot down here in Australia this time of year! The thermo will definitely be wide open! I have a trail tech so I'll now if it doesn't get hot enough. After my diagnostics, I'm expecting it to sit no colder than 80 C, which is slightly high (by about 5 degrees) but more or less ok in my opinion. Let me know what you guys think. There will certainly be opinions, as its a hot topic on 650R forums! Oh, I'm running Toyota red concentrated coolant at a 30% mix. It's not cold down here. All I want is the anti-corrosion properaties. If it were cold, I'd run it at 50%. I love Toyota coolant. Not a single problem in any vehicle in many many years and some of them aren't Toyotas.. Like this one..!

Interesting , i change my coolant every two years , to prevent any build up inside the system .

I just edited this post. I got my information wrong! I'm over dodgy thermostats. Shortening the cage was a bad idea. The bike runs cool still. Don't know why after the exercise I wrote about above!

I'm off to Suzuki for a 1990 swift one in the interim while I wait for the Fluidyne radiators and the 1.6 cap from Just XRs (not cheap!) I just ordered. I'll do a bunch of test riding in the heat and a bunch more reading but might put fans on too. I can't think of many reasons not to. Especially for social rides like all of mine are where you're stopping all the time to wait for the next guy at the next turn..

Mad Frosty wrote:Interesting ,  i change my coolant every two years , to prevent any  build up inside the system .

The Toyota coolant, red indeed, these days does not have to be replaced anymore, it's now "lifelong" lasting. Their previous version (also an organic acid, it was called Castle Fluid) had to be replaced after 40KKm (I know, odd, not a time but a mileage) to prevent it from making deposits, and it did too, I tried (got several Toyotas).
So, not anymore, and it's a good coolant for an aluminium (the XRR's) and/or cast iron engine.
But yeah Frosty, I also renew it willy nilly, it is cheap enough

I have seen many engines open , most of them had the original coolant still in ( various makes , cars and bikes ) , and i have noticed some gunk floating about and some white build up on the walls , never seen that on a well serviced engine , so that is why i recomend to change it once in a while 4-5 years should be the maximum IMO .

Suzuki go by models bot years. They wanted me to give them a VIN number of the car I wanted a thermostat for. A radiator shop couldn't find a swift thermostat that was offset either. I ordered the XR's only one, along with the 1.6 cap and Fluidyne rads. I'll definitely put a fan on each rad too..

5mman wrote:Suzuki go by models bot years. They wanted me to give them a VIN number of the car I wanted a thermostat for. A radiator shop couldn't find a swift thermostat that was offset either. I ordered the XR's only one, along with the 1.6 cap and Fluidyne rads. I'll definitely put a fan on each rad too..

You only need one fan , unless you are using it as a city comuter in very hot place

One fan works great, It will hold the temp to 200 - 205 deg f in hot slow riding.

Is that all custom brackets? Looks neat. What fan is it? Was planning on using a brushless high volume computer fan. They're quite ok with water & dust..

A friend of mine cut those out on his CNC he has in his garage.  The fan is off of a KTM but if you search SPAL fan on Ebay its the exact same fan and usually for a better price.  As soon as you attach the letters KTM to anything the price goes up.

Yo Eddy,

if this is your bike (I think?) you may want to put some washers between bracket & fan so as to 'shim' the fan's face closer to the radiator. I see a bitofa gap there, and fans have the nasty habit of sucking through there instead of through the fins, the lot becomes more efficient this way.
I also made a bracket (1 piece with bent sides to make it stiff) and did this, works well.

If ordering a Spal direct (not from/via KTM, is same fan so btw) the get the 4" puller, not push type! It is an automotive quality and it's a good one, it lasts.
(Edited later) The funny thing is, Spal is a US brand, but the fan is made in Italy

5mman wrote: I'll definitely put a fan on each rad too.

You can't, at least not a Spal 4" - not enough space, and no tank will fit anymore.
A very low-profile computer-psu fan (not environmentally sealed at all, they will break but are cheap) you may be able to fit on the LHS, but these pull very little air..... ask me, I've tried, worked too but I've discarded this setup.

Burp, you are correct about the gap between the fan and the radiator. I purposely left a small gap because I didn't want the fan shroud rubbing on the radiator tubes with the potential of rubbing a hole through one of them. It probably wouldn't happen but better safe than sorry. It works good enough you can start the bike with the fan on and let it sit there idling as long as you want and it wont overheat.