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Discussion Starter #1
This question has been on my mind so I throw it out for comments. Would it be a positive change for eng temp to remove the thermostat? I don't know the opening temp but given that coolant temps run as hot as they do the thermostat has to wide open all the time other than when first starting. The thought here is that the thermostat may be somewhat restrictive and taking it out would increase coolant flow. Other than a longer warm up period I can't find any logical reason for it to be in there. Comments please.
 

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lee said:
This question has been on my mind so I throw it out for comments. Would it be a positive change for eng temp to remove the thermostat? I don't know the opening temp but given that coolant temps run as hot as they do the thermostat has to wide open all the time other than when first starting. The thought here is that the thermostat may be somewhat restrictive and taking it out would increase coolant flow. Other than a longer warm up period I can't find any logical reason for it to be in there. Comments please.
The longer an engine takes to reach its operative temp, the more internal wear will occur.. I wouldn't recommend the complete removal of the stat.. However, your right in saying that once the stat has opened, it job is basically finished until the engine completely cools down again..
 

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Discussion Starter #3
I agree on the accelerated wear. Put that aside and assume the engine is up to op temp. With no thermostat to restrict the flow (if it does) would that result in more flow hence cooler temp? Particularly at idle when the flow isn't the greatest due to the pump's inability to move enough coolant?
 

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The thermostat does restrict the flow of coolant somewhat. I have heard that in full summer heat her at the racetrack, removing the thermostat did indeed drop the operating temperature. I think he said 10F, but didn't press for further details. By the way, this is from quite a reliable source, not some backyard hack. (He had just come back from Italy for service training on the Desmosedici.) The reason this came up is that I was asking about heat and mentioned a trick we used to do with cars.

The thermostat is essentially a washer installed in the coolant line. The center hole of the washer gets covered or opened depending on the temperature of the coolant. We experimented with drilling holes in the outer portion of that washer, so that even when the thermostat is closed, there is still some limited flow. My thought was that when open, this might give slightly better flow. His response, "Give it a try. It might help."

Perhaps I'll take a look at it today if I get around to that oil change I need to do.
 

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I used to 'run' an F40 LM (one of about 17 factory cars), no Tstat at all just a roll of Gaffa tape for water and oil rads and a Ferrari inst book of where to stick it!! the problem with taking the tstat out is if the bike drops to 62deg C it will drop onto it's warm up programme (choke) which will not be a 'proper' performance map and you may damage the engine :jsm: you wwill certainly lose performance, best left in I feel :)
 

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Discussion Starter #7
How often does an F4 1000 drop below 62C once it's up to op temp? And if it goes below 62 and the start circut cuts in then it's doing what it should, no? I think it's worth a try, and I'm going to do some testing with and without the T-Stat. Too bad it's 28 dgerees F with 6" of snow out there. But I can run it in the shop and get an idea I think. Or I could bundle my old ass up and play Nannook of the North. Wouldn't be a realistic test envoironment though.

F 40LM eh? You dog.
 

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I used to have problems with my 900SS running too cold. In the winter, I'd tape over the oil cooler, which had no thermostat. With the old 125 and 250 GP bikes, that was how we regulated temperature.

On the F4, I doubt that the temperature would drop too low once moving, but it would take longer to get there, and would be running rich until it was due to the system automatically simulating a choke.

I did just change my oil, but looked at the thermostat housing and decided, "nah, not today." Even if I had modified the thermostat as I suggested, it's not getting over 50F during the day right now, so I wouldn't know if it made a difference or not. The best time for this type of testing is gone for the winter. Perhaps I'll change my mind, or do it in another 3500 miles when I'm due for a valve clearance check.
 

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CAG said:
Why not try and find a thermostat that opens at a lower temp?
That's a good question, but presumes that one is available. That's another old hot rodder's trick. For the MV, I haven't checked. I doubt there's more than one value available.

From my previous experience, I used a cooler thermostat on a car that heated up very quickly and would show a spike of high temperature before the thermostat fully opened. Once the thermostat is fully opened though, the temperature rating of it doesn't matter anymore. If the higher temperature one isn't fully opened at normal operating temperature, a lower one might help.
 

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I suspect that the overheating problem would be resolved with larger capacity fans for the radiators. The overheating occurs when the bike sits in trafic not when it is moving at a decent speed. If the electric fans where sized up to flow enough air across the radiator when the temps are high then the temps should drop. I don't know if MV uses undersized fans due to clearance issues, cost, or whatever--but it seems to me that this is the proper fix.
 

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Has anyone tried putting in a sender unit that switches the fans on at lower temps ??

It wont stop the overheating issue at idle but would give you a bigger time window at the lights before high temps are reached.
It might be an easy fix for some people who go through traffic infrequently...
 

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lee said:
F 40LM eh? You dog.
Yep! real nice thing, it sat in a Japenese collection for many years before my 'man' bought it, he then started doing a few track days with the car before it all started getting a little too serious considering what the car is worth, he has now sold it on, I guess it is a once in a lifetime thing as it is probably irreplaceable.
This isn't his, but you get the idea, it has very little in common with a 'road. F40
 

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Discussion Starter #15
Triple,

Good idea, but I think it would be hard to find a lower opening temp sender that would (a) fit and (b) be compatible with the requirements of the circut.
Some of those things operate on resistance or voltage between two wires and would have to have an output that would send the correct signal to the ECU. I'm also not sure but I think the ECU gets it's engine temp readings from the same probe and changing it would alter the timing and A/F ratio.
 

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The sender in the rad only does the dash temp, I think it is also very inaccurate when the bike is moving at speed. the one by the stat goes to the ecu, the ecu starts the fans
 

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mikef4uk said:
Yep! real nice thing, it sat in a Japenese collection for many years before my 'man' bought it, he then started doing a few track days with the car before it all started getting a little too serious considering what the car is worth, he has now sold it on, I guess it is a once in a lifetime thing as it is probably irreplaceable.
This isn't his, but you get the idea, it has very little in common with a 'road. F40
Hi Mike

Yeah.. not bad I suppose, but I couldn't live with that Red..

Don't they do a nice Pearl orange in that model... NOT !!!!!
 

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Discussion Starter #20
I don't know yet as I got the bike too late before winter set in. I also want to mod the stock fans and add another one on the left side (Duc 1098 fan-small with curved airfoil blades). Once I get that done I'm going to run it in the shop and let it idle until it gets hot and then hit the switch and see what happens. It'll take some testing.
 
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