Is it OK to remove the 630 thermostat?

[XLEnduroMan]

The thermostat and extra cooling plumbing on the 630's is a pita. Anyone who has adj. their valves knows this. More plumbing = more potential for failure. The extra plumbing looks like it can easily be cleaned up and made free flowing like the smaller engines with the same dohc head. The smaller engines don't have a thermostat (right?), and the rads on the 630's look to be the same size as the other bikes. So why won't the 630 run at temp without a thermostat? I would rather eliminate the thermostat and related hoses then go through the pita valve cover removal again. 630 owners, what are your thoughts?

 

[jtemple]

I don't want to remove the thermostat. I would love to relocate it to make that valve cover easier to remove.

 

[CJBROWN]

How 'bout.....
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NO!!

 

[XLEnduroMan]

I can't help but try it. Our two '08 TE's don't have the extra cooling mess and they run great in all kinds of temps. (The 250/310 has an '09 ECU). We have had them out many times in the snow and cold weather. That is with the Hi Flo water pumps too. Surley I will be able to tidy it up on the 630's and make them less complicated and easier to service. It may take me some trips to the auto parts stores to source the hoses. As long as the 630 ECU plays nicely without the thermostat, (I don't see why it wouldn't) I am sure it will be better off. Our 630's for the most part only get ridden in the nice weather anyway.

 

[diverabe]

I know that cars would have a problem with that.I dont know what the ECU monitors and what it doesnt.If you take the t-stat out of a
newer vehicle it will know.It measures warm up time to calculate fuel trim,time to closed loop and other data.
Not sure how the computer functions on these bikes.Cars will set a check engine lamp real fast.

 

[CJBROWN]

My KTM250 4-stroke doesn't have one either and it always runs good. I still don't think I'd F-with it on the TE though.

Mine has seen some cooler temps and I don't worry about it running cold, it stays at an even temp. I think it's better for the motor in the long run. When they're cold they run more lean and fuel doesn't combust as completely. A fully warm motor is running at it's best.

 

[kingmoochr]

I have a wideband o2 gauge installed on my bike. the bike definitely runs richer for the first few minutes before it is warmed up. this indicates the ecu is reading engine temp and adjusting fuel accordingly. removing the thermostat isnt a problem as long as the bike reaches the ecu's "operating temp" and switches to the non-warmup fuel map. if it does not reach temp, you end up with a bike that will be overfueled. this is the same way cars work.

 

[organ donor]

We did a series of experiments on the 644DS CCM and tried to eliminate the oil cooler. It worked ok in winter but the oil thermometer screwed into the oil filler cap showed that the temperature rose to dangerous levels in early summer and the oil would have broken down. Don´t even try it without some method of measuring oil temperature.

 

[kingmoochr]

We did a series of experiments on the 644DS CCM and tried to eliminate the oil cooler. It worked ok in winter but the oil thermometer screwed into the oil filler cap showed that the temperature rose to dangerous levels in early summer and the oil would have broken down. Don´t even try it without some method of measuring oil temperature.

water thermostat, not oil thermostat, different animal.

 

[organ donor]

Yes ... but both show when the engine heats up too much. In Europe (as in most parts of North America) climate and weather changes can be extreme. Manufacturers cater for these extreme changes in temperature. Removing the thermostat could be appropriate in cooler conditions but then there would be no protection against overheating in warmer conditions (I tape up the radiator during the winter months).

 

[RDTCU]

Yes ... but both show when the engine heats up too much. In Europe (as in most parts of North America) climate and weather changes can be extreme. Manufacturers cater for these extreme changes in temperature. Removing the thermostat could be appropriate in cooler conditions but then there would be no protection against overheating in warmer conditions (I tape up the radiator during the winter months).

I think you got that backwards, it will run cooler without the thermostat as coolant will be circulating constantly...

 

[organ donor]

You´re right ... was thinking of removing the oil cooler in winter.

 

[hammer]

I think you got that backwards, it will run cooler without the thermostat as coolant will be circulating constantly...

You actually have a better chance of over heating without the stat because the coolant is constantly circulating.

 

[blakebird]

More plumbing = more potential for failure.

That's a bit of a stretch to support your reasoning.
How often are you in there adjusting valves? Is it really worth making that drastic a change in your cooling system to make that access marginally easier?

I didn't think it was a huge deal when I did mine - I did remove the one hose in the way to push it aside, had a tiny bit of coolant escape, plugged the hose and topped it off when I was done.

 

[RDTCU]

You actually have a better chance of over heating without the stat because the coolant is constantly circulating.

How so?

 

[pinocono]

How so?

If I may butt in, it's been my experience if you simply eliminate the thermostat, the coolant may circulate too quickly, and not get cooled down enough as it passes through the radiator(s). I used to have a '67 Mustang with a modified 289. Living in Southern California, I just tossed a malfuctioning thermostat. The car overheated. I found out that if you pull the thermostat in a small block Ford, you need to replace it with a restrictor with a 5/8" hole in it to slow down the circulation, allowing adequate heat transfer (cooling).

 

[hammer]

How so?

The stat has one real function, to keep the coolant at a specified temperature. To do this it stays closed until the coolant in the engine is warm enough to open the stat. Cool coolant is then introduced to the engine and also closes the stat. This gives the hot coolant time to cool in the rads and the cycle continues.
If the coolant is circulating continually it will stay too cool in cold weather or get super heated in hot weather.

http://en.wikipedia.org/wiki/Convective_heat_transfer

 

[hammer]

If I may butt in, it's been my experience if you simply eliminate the thermostat, the coolant may circulate too quickly, and not get cooled down enough as it passes through the radiator(s). I used to have a '67 Mustang with a modified 289. Living in Southern California, I just tossed a malfuctioning thermostat. The car overheated. I found out that if you pull the thermostat in a small block Ford, you need to replace it with a restrictor with a 5/8" hole in it to slow down the circulation, allowing adequate heat transfer (cooling).

Yes you beat me to it.