I disagree, there is no threat of over-cooling the TR650. However, there is a potential issue with the oem thermostat as I see you have changed yours. I have two large street bikes and one is a 1200. Neither of these have thermostats and only require a few more minutes of warm up before I ride. I have no problems with either machine and I have never stranded in the middle of no where over heating. I can make the bypass if you guys want. My coolant will flow past the oem thermostat no problem either way, I am only trying to help you guys out.
Here is a quick crude sketch of what it could look like. Should be easy to turn on a lathe. I do not think an o-ring on the inside is needed, might be better to not have one, to let air bubbles purge. Some sort of design on the bottom end for removal. Maybe a threaded hole to put a handle in or even a temp sensor.
I wanted to talk a little bit about this. For me, the thermostats purpose are very important, due to my riding style and wish for a long lasting engine. There are some positive effects of running the motor cool. Those do not interest me, for my style, but for others, more oil changes helps. If the motor is running cooler, the efi is going to add more fuel. This got me thinking again of the TR650 fueling issues, and why some may have bigger trouble than others. Right now, my bike is running right at about half on the temp gauge. In past reading, some others bikes run warmer. Dropping down to a 185 thermostat, might help the bike run better, if you have a real lean one. This mod may have some really good advantages in drivability beyond the burping issues. The running temp of the TR650 may be for an EPA requirement, not a performance spec. Run warmer, better fuel efficiency, run cooler, more power. I will run a t-stat. The heating and expanding of the metals and gaskets and parts will take it's toll over time, and I'm looking forward to 100k miles.
I absolutely want to run a T-stat. My only concern is the reliability of the rather fragile appearing stock plastic components surrounding the OEM t-stat. I fully believe in a stable operating temperature in a reasonable zone. Too cold is bad, too hot is bad, something in the 185 - 190 deg F seems pretty good with an upper "max" temp around 210 or so. So far mine seems to run just a tad above mid range on the meter but I have no idea what actual temp that is. It seems pretty stable overall and I like that, it's not swinging all over the place rapidly. Sure it goes up in stop and go traffic or very slow going, that's expected. Then the fan kicks on or I start to move faster and it cools back down. I simply want to keep it running that way reliably. I think we'd need to look to the BMW sites to see where and how this unit frequently fails to have a better understanding. Based on the info in the F 800 diagram it appears they've been using this design for quite some time so it's history "should" be well established.
Feel free to disagree. In an environment that is roughly guessing 80*F or hotter your temps will likely stay stable regulated by the electronic operated cooling fan. What you need a properly heated motor for is better fuel atomization, proper oil temp(that's a big one) less carbon build up and a few others. Longevity is the key here. As for the potential issues with the thermostat I really don't believe there is one besides its tricky to purge air. People have bought air locked bikes new on this forum. There is a learning curve on the cooling system on the TR, not a problem. As I stated before once you bleed the system properly this bike will NOT overheat. I've proven this myself.
If we need a thermostat there are inline and bypass thermostats. Something like this http://italianmotorsusa.myshopify.com/products/iame-thermostat.
Yes the tool applies a vaccum to the system. This also serves as a test to the integrity of the system itself as you cannot pull a vacuum on a cooling system with a hole in it. The vacuum pulls coolant into the system. This means that even if you have a hose running higher than the radiator fill or a cavity it will be filled. This is a YouTube demonstration I found just now. This is the tool I have, but there are others out there. Tool name and part# is: Uview Airlift 550000 View: http://youtu.be/FQnfUe6P5VI
Is there a write up anyplace describing a good procedure for bleeding out the cooling system for these bikes? I have had this issue before with a few cars, it can be tricky to get the air pockets out if there's no "highest point" vent/purge valve.
I'm guessing from reading through all of these posts, if you raise the front of the bike using a lift, chain hoist or ratchet straps and get the head of the engine level with the floor, then you could bleed it properly. But the thermostat still remains in question.
I had good luck burping the hoses. Just squeezing every hose till they where full of coolant. I watched the radiator to make sure no air bubbles where present. I have a Jeep Cherokee and everyone has to burp the hoses to get the air out of the system.
I ordered a thermostat housing and I will prototype when I get the items. If you wish a thermostat, thank Glengemen for finding a Meziere inline thermostat housing, not sure where to find one with 1" hose barb ends though, might be a direct item. There are many high flowing thermostats available for the housing. You may wish to see his original post to see the specifics.
Yes, this is a unlisted part. I called on the off chance that there was a 1" available. I spoke with Jerry he can be contacted at (760) 746-3273.
The vacuum fill method of filling your coolant system is what I have seen any professional car builder use. ALthough they let the gauge stay on over night to make sure there is no leaks.
Something to think of is around town the automatic fan will regulate temprature as needed. The only issue would likely be in extremely cold climates cruising at high speed low rpm where the radiator is at maximum airflow. I still will put $$$ on the fact that it will not cool below the thermostats opening temprature. Would not make sense to design a system that if you ride down the freeway at a certain speed at low temp, that the thermostat would be cycling on and off. I dont buy it.
You guys are pretty smart and may reengineer the cheesy thermostat to work with all of those hi-tech fluids. That would be an accomplishment for sure. The (cheesy) thermostat is one of two faults of the rotax engine (the other being rough cut gears that need to be back-cut to keep from grinding AND splitting the case to get to them.) And since it is manufactured for the minimum cost over 20 years with no development in the thermostat (95% C.I.,) the probabilities of successful transformation diminish. BMW Chain gang members have reportedly tried electronic thermostats with pretty good results, with several innovative stages of development. The whole oem system is faulty because it is based on a $3.50 automotive thermostat: nothing you do can change that. You guys are racers so you may figure it out in a matter of a couple of weeks with or without their previous 15 years random development from other smart professionals (not racers.) Racers rule.
