Another one Bites the Dust

[Tinken]

So does the thermostat allow hot water to flow directly to the cold output side, bypassing the heat exchanger?

 

[mag00]

This is looking up from the bottom of the tank to show where the thermostat pin fits and pushes off of.



And this next photo is the one that has me puzzled. The area is the alleged partition from lower and upper radiator flow. That little rubber piece is inexplicable to me at this time. There is a small passage from the top to bottom, right above the rubber flap when radiator is installed.



If you look at the bottom of the opening, you will see a hacksaw slice. What is that about you may ask? Well, to get this apart was a bugger. This radiator was the one from the "fire damage" on ebay. It may have been ultra stuck because of the fire. I cut to relieve the stress, reached in where the hose was and pushed from the inside, used the pry points that seem to be designed into the tank, and still had trouble breaking it free.

Also, for reassembly should you wish to go stock, it is nearly impossible to get that pin to line up with the socket. The week point in this assembly seems to be where the spring seats in the black housing. It is plastic, and the little 4 little tabs on the bottom break, as well as the cage tabs on the top.

The real fix is posted as the real fix above.

But... if the motor was designed to keep a constant flow of even temp coolant around the cylinder, then oh well.

Here is where I struggle. If the high tech design of the radiator and thermostat is the best for the engine, that is what needs to stay. This is where the appeal of the waterless coolant becomes relevant. It stops corrosion and deposits from fouling the delicate system.

Does optimum engine life and performance come from a steady operating temp?

Is it enough to worry about?

Now to the issue of removing the thermostat. I guess trial and error is the best method.

Looking at and trying to understand what really goes on with the flow is interesting. My guess is that the design of thermostat assembly is more of a balance valve to divert pressure for the scavenge of the fluid from the top hose. The balance of porting and clearances looks like when the thermostat moves, it simultaneously change the other portion of the assembly, making a path of least resistance for the suction of the water pump to draw from either the top half or bottom half. When drawing from the top half, the coolant flows through the radiator, and the cool fluid mixes with the hot in proportion to the engine need.

This is just a theory I came up with, makes sense to me, but could be totally not the case. I have a waterproof bore camera I am thinking about using hmmm, very interesting indeed.

 

[mag00]

So does the thermostat allow hot water to flow directly to the cold output side, bypassing the heat exchanger?

That appears to be the case.

The bottom is open and fluid flows up past the spring. When the pin expands, it opens the seat, and closes that section between the two ports past the spring. To remove the thermostat, you would need to glue something in there after you remove the brass and the middle spring assembly. The pin pressure is what holds it all together. The bottom large open cage would be the part to modify.





If and when this system fails, I will go to a cross flow radiator as done by glengemen.

 

[Tinken]

I think what we can do is make that entire piece you have in your hand out of aluminum. There is an o-ring on the bottom, but we can add one at the top to separate the hot and cold outputs.

 

[mag00]

I think what we can do is make that entire piece you have in your hand out of aluminum. There is an o-ring on the bottom, but we can add one at the top to separate the hot and cold outputs.

The BMW guys would love you too. While I understand the concept of the continuous flow design of the factory config, I think this mod would be far more reliable.

 

[Tinken]

Do you have a part number for that thermostat by chance?

 

[danketchpel]

Do you have a part number for that thermostat by chance?

I don't see a callout in the parts manual for the thermostat by itself, not good. I don't even see a part number for the cap by itself! So you buy a whole radiator to get the cap???

 

[danketchpel]

Here is where I struggle. If the high tech design of the radiator and thermostat is the best for the engine, that is what needs to stay. This is where the appeal of the waterless coolant becomes relevant. It stops corrosion and deposits from fouling the delicate system.

Does optimum engine life and performance come from a steady operating temp?

Is it enough to worry about?

Yes, maintaining a fairly constant engine temperature is important to the life of the engine and consistent fueling.

The Kawi KLR650 has a very silly thermostat and coolant routing in stock condition and allows the engine temps to swing all over the place. An aftermarket thermostat and coolant routing system was developed called the Thermobob. I installed one on my KLR and it improved engine temp stability dramatically. One of the design aspects of the T-bob is allowing coolant to recirculate back to the engine while it's warming up which makes huge sense. The coolant should always be circulating to avoid hot spots and micro steaming.

Honestly in stock condition and in proper working order I see the temps of my Husky quite well controlled. I don't mind if the fan comes on frequently, that just means they put the thermoswitch temp setting for the the fan circuit low enough to start cooling sooner rather than when it gets way to hot. Modern cars work the same way keeping the coolant temps very close to ideal.

I don't see anything wrong with Husky's design. My concern is being able to source replacement parts (t-stat & cap w/o buying an entire radiator assembly) and keeping the system clean and in good working order.

 

[Gibster]

Do you have a part number for that thermostat by chance?

The BMW 650 single uses a similar set up. The thermostat is available, but no idea if it is the same.

 

[mag00]

The BMW 650 single uses a similar set up. The thermostat is available, but no idea if it is the same.

Yes, maintaining a fairly constant engine temperature is important to the life of the engine and consistent fueling.

The Kawi KLR650 has a very silly thermostat and coolant routing in stock condition and allows the engine temps to swing all over the place. An aftermarket thermostat and coolant routing system was developed called the Thermobob. I installed one on my KLR and it improved engine temp stability dramatically. One of the design aspects of the T-bob is allowing coolant to recirculate back to the engine while it's warming up which makes huge sense. The coolant should always be circulating to avoid hot spots and micro steaming.

Honestly in stock condition and in proper working order I see the temps of my Husky quite well controlled. I don't mind if the fan comes on frequently, that just means they put the thermoswitch temp setting for the the fan circuit low enough to start cooling sooner rather than when it gets way to hot. Modern cars work the same way keeping the coolant temps very close to ideal.

I don't see anything wrong with Husky's design. My concern is being able to source replacement parts (t-stat & cap w/o buying an entire radiator assembly) and keeping the system clean and in good working order.

Thanks for that. The Thermo-bob, that is the ticket, and put in the replacement bypass cage in the radiator. Or just modify the stock one. http://www.klrworld.com/index.php?o...k=view&id=193&Itemid=286&limit=1&limitstart=1

I'd like my fan to come on sooner. I bought the spare radiator and fan assembly for the fan (and hard to find parts) , and was going to add a secondary fan for slow trail work. It don't fit on the opposite side of the frame. When I get ambitious, I'll look for a smaller fan to mount.

 

[mag00]

Do you have a part number for that thermostat by chance?

I don't. There is nothing written or stamped on the brass. The numbers on the seat as pictured earlier is all that there is.

Seems I looked for them back when I was doing this, and they are available for around $70.

You saw the part in the tank that holds the pin right? Well, the photo really doesn't show how cheezy that is. That scares me.

Then, on the bottom of the thermostat assembly, the last picture I posted, those black plastic tabs that hold the spring break. Go figure, tiny little plastic tabs. The concept of circulation I love, as the thermo-bob, the execution of manufacture and design is what is lacking in this system.

If you search photos for bmw g650 thermostat, you will see these things are failing.

I have one concern, and that is about expansion of the parts. I do not know the expansion rates of plastic vs aluminum. I would assume the O-ring seal should be sufficient for the expansion.

I'm going to snoop around the hardware store for cpvc of that diameter. If an end cap is close diameter, making it out of plastic would be an good DIY project. And the beauty of the waterless is that there would be no real pressure to blow it apart. I'm just going to need a bit of time before I try waterless again. I need to get some worry free miles on the bike again.

If you can't find a part local to pull dimensions, I can lend you the small parts. Not sure I want to send the radiator, but I can get accurate dimensions of the bore. Glengeman may be able to lend out parts as well.

 

[Glengemen]

How did you remove the oem thermostat before putting yours inline?

Hold this train here people. Don't start trying to remove thermostats from you stock radiator!! I suppose that is if you don't want the hot water to make a constant loop with little to no cooling. The plug idea cold work, but the #1 thing to remember in this is that the coolant must be forced through the core before going to the other port.

I have welded on side tanks and there is a baffle on mine to force the coolant to flow into the core. I removed my thermostat and placed it in line with am aluminum housing. I never ran mine without a thermostat.

Running without a thermostat on the street is no good. You will over cool and give you a whole new set of problems. These aren't race bikes that are running wide open all the time. You need the heat in the TR.

 

[RidingDonkeys]

Mag00, sorry to hear about your troubles but happy that they are bringing some issues to light. Thanks for detailing this whole operation for the masses to see.

 

[lankydoug]

You eggheads are making more out of this than it deserves. The thermostat basically blocks and serves to re-direct fluid to bypass the rads when its cold and blocks the bypass when it's hot, opening the flow to the rads. I think Tinken is suggesting machining an aluminum plug that simulates an open/hot thermostat. Problem solved. I'm sure he would drill a small .030" hole in it to prevent air lock in the bypass circuit. Yes it would take the engine longer to warm up... So what? Pretty much every race MX engine has no thermostat and are having none of the imagined thermal expansion problem you are theorizing.

 

[Glengemen]

You eggheads are making more out of this than it deserves.......Pretty much every race MX engine has no thermostat and are having none of the imagined thermal expansion problem you are theorizing.

I agree that a MX bike needs no thermostat. It is ran hard always and would always have an open thermostat. Problem is that this is not an MX bike. It needs to operate in its intended range. Especially true in cold weather. I'm in a range of 120-20F ambient, the thermostat makes it run the same in all temps. If you think this bike would do well operating at 100F coolant temp I'm pretty sure that would be incorrect.

 

[lankydoug]

I

I agree that a MX bike needs no thermostat. It is ran hard always and would always have an open thermostat. Problem is that this is not an MX bike. It needs to operate in its intended range. Especially true in cold weather. I'm in a range of 120-20F ambient, the thermostat makes it run the same in all temps. If you think this bike would do well operating at 100F coolant temp I'm pretty sure that would be incorrect.

I don't know the details of the mapping system but if it's got a temp sensor and a programmable ECU then it can be mapped for various temps. Don't get me wrong I'm not saying it's the best set up for ice racing but the original post suggests that it overheated which means the problem wasn't that it was running too cold.

 

[drzcharlie]

AIT spoofers get negated (usually) by the ECU and reverts back to the original fueling scheme. Nobody has broken the MM ECU's Hexcode yet so we can't change fueling maps yet.

 

[danketchpel]

You saw the part in the tank that holds the pin right? Well, the photo really doesn't show how cheezy that is. That scares me.

Then, on the bottom of the thermostat assembly, the last picture I posted, those black plastic tabs that hold the spring break. Go figure, tiny little plastic tabs. The concept of circulation I love, as the thermo-bob, the execution of manufacture and design is what is lacking in this system.

If you search photos for bmw g650 thermostat, you will see these things are failing.

I have one concern, and that is about expansion of the parts. I do not know the expansion rates of plastic vs aluminum.

I agree, it's not the concept or overall design I worry about, it's the delicate plastic parts in a sprung condition I'm not real keen on.

I agree 100% it should have a thermostat, it's not a race bike operating under fairly fixed conditions. A well controlled engine operating temperature goes a long ways towards longevity compared to one that fluctuates all over the place. Running too cold allows water build up in the oil which doesn't help at all.

I'm in the plastics industry and the typical expansion rate for most plastics is in the 0.003" - 0.010"/inch range. Some are more but not the type used for this application. 6061 Aluminum is about 0.000013"/inch thermo expansion, so far less.

 

[danketchpel]

The BMW 650 single uses a similar set up. The thermostat is available, but no idea if it is the same.

I found this for the BMW F800 which appears to be of the same design. The thermostat is available separately for $42. I suspect some digging might turn up a suitable replacement but can't be confirmed until somebody can examine them directly.

Here's a shot of the assembly and part#s

 

[drzcharlie]

Nice find on the T stat.