The real radiator fix.

[Mark_H]

Mark, the thermostat does not cover the inlet or outlets of the radiator cores - effectively the radiator is 2-pass - the thermostat allows colder coolant to bye-pass the core - as the coolant heats up the thermostat closes off the bye-pass, directing more flow thru' the cores

I fully understand the Tr650 layout and system which is as you say quite clever in its design allowing a continuous flow. I was quoting the general set up of thermostats on a liquid cooled engine, example a car where the coolant does not even leave the engine until the thermostat opens to allow flow to the radiator.

 

[Mark_H]

Someday when you actually get your thermostat out, take a closer look at it. If it worked as intended, we wouldn't be sitting here having this conversation.

I do not need to remove my thermostat to understand how it works and how the coolant has to flow over it to make it operate, just like any other Thermostat.
Please try to understand, if there was actually no flow when it is cold/closed, there would be little or no heat and it would never work- simple as that.

By the way, the thermostat on a TR650 is actually open in the cold position, ie it allows full flow past it and straight back out of the right side of the radiator. When it is heated it closes off the short bypass and redirects the flow across the radiator to achieve more cooling. It actually operates in a balanced sort of way allowing and restricting the flow according to the coolant temperature in such a way that it never closes anything off completely.
As Engineerk9 says, quite a clever design, despite its possible faults.

 

[Tinken]

That's not true, there is no free flow when cold. If the valve doesn't open, coolant can only force it's way around the thermostat body to exit. Even when hot and the valve is open, the flow is not full, there is obstruction by the device.

 

[Tinken]

Better yet, why don't you draw us a diagram how you think this works.

 

[danketchpel]

Like I said - You do not need a thermostat in California, so why bother ?

Mark, actually a thermostat is still very useful in California as we do encounter "colder" temps while riding year 'round. In P.I. I think it may be "optional" due to very consistently warm temperatures, but here it has a purpose.

I have been riding my air/oil cooled Moto Guzzi Stelvio to work for the past month or so with temps in the low to mid 50s (F) while I'm riding in the morning and evening. I just did the 25k mile service on it and while pulling the valve covers off to check/adjust the valves found this yucky white stuff on the outside leading edge of the valve covers which is basically condensed water emulsified in oil. This happens when the engine doesn't get up to temperature long enough to "boil off" the water condensate that collects in the engine. My mostly freeway commute is about 16 miles/20 minutes long, so obviously not long enough to get an air cooled engine in cold air fully up to temperature long enough to drive out the water condensate. This is not typical in warmer conditions and the only time I've seen it as it's the first time I've done a service in the winter. While I've ridden the bike year 'round from purchasing it new, this is the first time a service interval has landed in the dead of "winter" as we know it here. I've confirmed this condition with other Guzzi owners who live and ride in much colder climates, it's typical when the engines don't get fully up to temperature. This is with running high quality 100% synthetic oil.

This is the same thing that will happen to liquid cooled engines if they don't get fully up to temperature. I experienced this with a forklift engine that ran for short periods at a time also, though it was far worse, almost disgusting.

There really is a need and purpose to keeping the engine at a suitable operating temperature range and why EVERY manufacturer puts a thermostat in the cooling system, even going back decades before emissions were a part of the picture. It's a huge drawback to air cooled engines and one reason for the move to liquid cooling. Not only does it allow for pulling more heat out, it allows for maintaining a desirable operating temperature range.

Here's pix of the valve covers with the yucky white condensate in the leading outside corners. The rest of the engine was clean as was the oil that drained out. Though I can't say that for the forklift I had, when I pulled the oil of that it was really mixed white "mayonnaise" and oil, seriously disgusting.

Right side;


Left side;

 

[engineerk9]

Better yet, why don't you draw us a diagram how you think this works.

Very rough sketch, will give you the idea of what would work

 

[Nick780]

This is the same thing that will happen to liquid cooled engines if they don't get fully up to temperature. I experienced this with a forklift engine that ran for short periods at a time also, though it was far worse, almost disgusting.

Oh..... Is that what this is?

 

[engineerk9]

View attachment 63476

Oh..... Is that what this is?

Very common on engines running stop/start frequently & only operating for a few minutes at a time
Residues being that white could be something else, usually they are a brown or darker depending on the amount of carbon in the oil
The TR has a much smaller engine mass than a forklift, therefore coming up to temperature quicker
In your case I might be looking deeper into the cause

One of the major reasons to maintain the ideal operating temperature is to ensure precise clearances within the motor, cold would mean wider piston/cylinder etc

Aircooled are by design wider clearances to accommodate the varying temperatures

Good that you are using full synthetic, possibly a 0-30 sae would be suggested to improve circulation

I think by nature Guzzis are "cold-blooded", perfect is southern Italy, but not quite is freezing north america

Mineral oils are more prone than synthetics

 

[engineerk9]

Very common on engines running stop/start frequently & only operating for a few minutes at a time
Residues being that white could be something else, usually they are a brown or darker depending on the amount of carbon in the oil
The TR has a much smaller engine mass than a forklift, therefore coming up to temperature quicker
In your case I might be looking deeper into the cause

One of the major reasons to maintain the ideal operating temperature is to ensure precise clearances within the motor, cold would mean wider piston/cylinder etc

Aircooled are by design wider clearances to accommodate the varying temperatures

Good that you are using full synthetic, possibly a 0-30 sae would be suggested to improve circulation

I think by nature Guzzis are "cold-blooded", perfect is southern Italy, but not quite is freezing north america

Mineral oils are more prone than synthetics

This thread was started by members concerned about the reliability of the thermostat & possibly not fully understanding it's relationship with the cooling system

 

[danketchpel]

This thread was started by members concerned about the reliability of the thermostat & possibly not fully understanding it's relationship with the cooling system

No, this thread was started by the OP in regards to working out a fix for the fragile plastic radiator header tanks. His tanks had cracked (failed) due to a crash. He stated his fix as being aluminum tanks.

That is why I followed up with this thread in my intention of having custom aluminum radiator tanks built to replace the fragile plastic tanks.

The bit about the T-stat is a bit incidental in that it needs to be replaced by something else once you build custom "normal" tanks that don't include the T-stat.

I fully believe in the usefulness of a T-stat and described my solution for replacing the stock in-tank one with an inline one, basically the same as the OP, only a different source and slightly different design allowing for a coolant bypass during warm up.

 

[Tinken]

Why did you draw me a sketch of a thermostat block off? I know how to make a block off, I made the one in the image below. Gluing a disk to the top of a plastic frame and hoping it doesn't separate and kill your $10k motorcycle is mind boggling.

What I asked for was a sketch of normal operation of the BMW thermostat.

By the way, the thermostat on a TR650 is actually open in the cold position, ie it allows full flow past it and straight back out of the right side of the radiator. When it is heated it closes off the short bypass and redirects the flow across the radiator to achieve more cooling. It actually operates in a balanced sort of way allowing and restricting the flow according to the coolant temperature in such a way that it never closes anything off completely.
As Engineerk9 says, quite a clever design, despite its possible faults.

The part of the quote I underlined is incorrect. There is no valve to shut off the minimal flow past the thermostat in it's cold position.



Coolant must flow around the outside of the upper lip of the thermostat support frame and there isn't a lot of room. There is very little flow in this position. During a failure, temperatures could rise so rapidly, even before one would notice it on a gauge. If the thermostat does open, there is nothing to shut off the coolant from bypassing the heat exchanger either other than the obstruction of the thermostat frame lip. This is a very poor design which BMW no longer uses on any of it's models.

The best fix is to replace the heat exchanger completely and add a thermostat to one of the external lines. Or add the Zipty delete. If that is too much to import, then throw a piece of delrin on a lathe and cut one like the ZipTy unit.

 

[danketchpel]

View attachment 63476

Oh..... Is that what this is?

Umm.... well yes, it looks to be the same yucky mayonnaise looking condensate.

It is not uncommon and most often the result of the engine not running at a warm enough temperature for a long enough time to boil off the natural water condensation (from the atmosphere) that occurs in every engine.

 

[engineerk9]

Why did you draw me a sketch of a thermostat block off? I know how to make a block off, I made the one in the image below. Gluing a disk to the top of a plastic frame and hoping it doesn't separate and kill your $10k motorcycle is mind boggling.

What I asked for was a sketch of normal operation of the BMW thermostat.



The part of the quote I underlined is incorrect. There is no valve to shut off the minimal flow past the thermostat in it's cold position.

View attachment 63477

Coolant must flow around the outside of the upper lip of the thermostat support frame and there isn't a lot of room. There is very little flow in this position. During a failure, temperatures could rise so rapidly, even before one would notice it on a gauge. If the thermostat does open, there is nothing to shut off the coolant from bypassing the heat exchanger either other than the obstruction of the thermostat frame lip. This is a very poor design which BMW no longer uses on any of it's models.

The best fix is to replace the heat exchanger completely and add a thermostat to one of the external lines. Or add the Zipty delete. If that is too much to import, then throw a piece of delrin on a lathe and cut one like the ZipTy unit.

I think Tinken we'd better agree to disagree on the way the thermostat operates in the TR

 

[engineerk9]

No, this thread was started by the OP in regards to working out a fix for the fragile plastic radiator header tanks. His tanks had cracked (failed) due to a crash. He stated his fix as being aluminum tanks.

That is why I followed up with this thread in my intention of having custom aluminum radiator tanks built to replace the fragile plastic tanks.

The bit about the T-stat is a bit incidental in that it needs to be replaced by something else once you build custom "normal" tanks that don't include the T-stat.

I fully believe in the usefulness of a T-stat and described my solution for replacing the stock in-tank one with an inline one, basically the same as the OP, only a different source and slightly different design allowing for a coolant bypass during warm up.

I have a question regarding this - the radiator is a 2-pass, with the external thermostat how do you manage flow thru' both passes?

Tinken's delete would be one way - without this the coolant would bye-pass the cores & the motor would over heat

 

[Tinken]

He welded a new divided end cap onto the heat exchanger.

 

[mag00]

View attachment 63476

Oh..... Is that what this is?

Glad I live in the desert. No high dollar oil is substitute for regular oil changes.

Why did you draw me a sketch of a thermostat block off? I know how to make a block off, I made the one in the image below. Gluing a disk to the top of a plastic frame and hoping it doesn't separate and kill your $10k motorcycle is mind boggling.

What I asked for was a sketch of normal operation of the BMW thermostat.



The part of the quote I underlined is incorrect. There is no valve to shut off the minimal flow past the thermostat in it's cold position.

View attachment 63477

Coolant must flow around the outside of the upper lip of the thermostat support frame and there isn't a lot of room. There is very little flow in this position. During a failure, temperatures could rise so rapidly, even before one would notice it on a gauge. If the thermostat does open, there is nothing to shut off the coolant from bypassing the heat exchanger either other than the obstruction of the thermostat frame lip. This is a very poor design which BMW no longer uses on any of it's models.

The best fix is to replace the heat exchanger completely and add a thermostat to one of the external lines. Or add the Zipty delete. If that is too much to import, then throw a piece of delrin on a lathe and cut one like the ZipTy unit.

Possibly 3d print one out of good material.

Then install the Thingamabob, or doohicky like the KLR folks use.

For reference again, http://www.cafehusky.com/threads/another-one-bites-the-dust.45824/page-2#post-449283

 

[Mark_H]

Better yet, why don't you draw us a diagram how you think this works.

Here is your answer....remember a long time ago when you were asking how it worked?

Your question was.....

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

And the guy who knew the answer said......

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.

So.....no diagram needed cos that is how I (and you) know how it works.
Once again I re-iterate there is no way that there is no flow in the Cold position and also no way for the Thermostat to fail and close the coolant flow off completely - which is what you originally said a few days ago.

 

[danketchpel]

I have a question regarding this - the radiator is a 2-pass, with the external thermostat how do you manage flow thru' both passes?

Yes, Tinken's answer "He welded a new divided end cap onto the heat exchanger." is correct. I will be replacing both end tanks with custom fabricated aluminum ones that will be welded to the stock core. I will have the guys at Fontana Radiator design the baffle(s) in the tanks for best flow, but essentially the right side will be divided as depicted.

I plan to change the hot return coolant input location to near the top of the right side, just under the fill cap location. Then the radiator flow will look like this, only the fill port will be on the right side.

 

[Glengemen]

danketchpel, sorry for the slow response as I'm not on here very much.

My side tanks were fabricated by Motor Mission here in Las Vegas. It was a long while ago and I'm sure to make a copy it would be from scratch.

The tank design is very simple though and could be done by any good tig welder. The hose side where the thermostat was has a baffle. This baffle has a 1/4" hole in it. The opposite side is simply an open tank. The cap neck is a prefabricated part holding the stock cap. The brackets are welded and bent to fit the mounts.
The thermostat housing is a 1" and is not listed on the Meziere website. I called to see if they have one and they did at the time. The hoses are 1"silicone. Doing it over I'd just use heater hose and rubber preforms. I have $100 in hoses!!
There is no bypass on my bike. I didn't feel the need to complicate things further.
I am a master mechanic and do 100% believe in using a thermostat on this motor. If I didn't it would have saved me over $100 in parts.

The bike runs as good as the stock setup with the same temp indicated on the graph. This is in 120-25 degrees. I run prestone coolant from the local parts house.

The most important thing you can do afterwards is get all the air out of the cooling system. I use a vacuum filler with perfect results. I have not tried it but I believe good results can be had by lifting the front of the bike so the can is perpendicular to the ground while filling.

Best of luck and I would do it again in a heartbeat over buying a new factory radiator.

 

[Tinken]

I don't personally own a 650, so when I asked the question of how it worked, it was long before I had one in hand. Another issue is that the 5 or 6 of them I have taken apart came with fully encapsulated thermostats which do not allow coolant up through the center like They were originally designed on the BMW1200. These units flow coolant around the outside of the thermostat frame. I assume, it's these encapsulated units really having the cooling issues. As with everything else BMW gave to Husky to sell, they just tossed in whatever misc parts. Regardless of those facts, there is extremely limited flow, even when fully functional. This is we'll documented on Adventure Rider and several other BMW forums. Whichever way you choose, I would switch to a different system or get the 1200 model which is larger in size as it was originally designed.