Thermostats for increased engine temps

[teal_210]

This is also an option:

http://www.helmarparts.com/product_p/m456-1.htm

I have something similar to this installed in the hose coming from the cylinder. So far so good, I was worried about the system building too much pressure and blowing the water pump seal, but it seems to allow enough flow through the thermostat to not cause any problems.

My trail tech stopped working on the first ride with a thermostat, so I haven't been able to watch the water temps. Hopefully I will have it back this week.

 

[Snowoff311]

So is this something that would need to be removed for summer riding or will it function just fine?

 

[sniffone]

2011 yz450f with raptor 660 thermostat

This is what I used for a thermostat raptor 660, then for the temp sensor from the trail tech I drilled out the raptor sensor and pipe tapped it 1/4" then I got a fitting from fleet farm that went from 1/4" to 1/8". Then the sensor screwed into the 1/8" end. Then I also built a flat piece of aluminum 4"x9" to cover the left radiator under the luvers.

 

[PalousePoo]

Sniffone, goodlooking bike, what I can see. Looks like you have an oil cooler on it too. Is that for summer time, mostly?

 

[sniffone]

I have pictures on a different thread of the whole bike. The oil cooler is for summer but I am going to try it see waht happens with the oil temp, I might block that radiator from the bottom up to where the oil cooler is, to try and keep the temps up.

 

[mtn-doo]

I was hoping it would be closer to 180 F.

Here is the new test unit. The bikes will solve a lot of little issues if they were operating in the 180/190 range. I would caution against blocking off a radiator. We tried that with inconsistent results. An automatic thermostat keeping temps in the 180/190 range with no hastle would be ideal. This "thermo-bob" 190 degree set-up might be the one ? Let's try it.

http://www.klrworld.com/index.php?o...k=view&id=193&Itemid=286&limit=1&limitstart=1

 

[summitboy]

Randy, does your AF have only one inlet on the head with the AF conversion ? On a stock 500 head you have two inlets. I see why some ice racers use two stats in the lines going down to the head. I see u only run one. I'm guessing one inlet only on the KX motor.

 

[mtn-doo]

Randy, does your AF have only one inlet on the head with the AF conversion ? On a stock 500 head you have two inlets. I see why some ice racers use two stats in the lines going down to the head. I see u only run one. I'm guessing one inlet only on the KX motor.

Yes, there is one large line leaving the top of the head. It is a large single line for a few inches then "Y"'s and feed's the top of each radiator. The flow is down through the rad's, out the bottom of the red's, into the lower case, through the water pump, then up through the cylinder and back out the head again. You want to place the thermostat in the line leaving the head going to the top of the radiators. Important to also install it with the "direction of flow" correctly. The thermostat needs to be installed with the flow direction going "from" the head, flowing "into" the top of the rad's. One is all you should need, unless that line below the "Y" is so short you don't have enough length to get it there. Then one in each branch of the "Y", flowing "up" will work.

It is important to know the direction of flow and the proper place to install the thermostat. I have had a few bikes that I helped trouble shoot and found the thermostat was in the wrong location or facing the wrong direction.

 

[snorider99]

So whats the easiest way to figure out the ''direction of flow''?

 

[albertaguy]

So whats the easiest way to figure out the ''direction of flow''?

the ktm thermostat I picked up has a small extra 1/4" outlet that you block off which points down and to the outside on my 13 kx450f. Pretty much one straight line coming up from the bottom (inlet) then it y's to go to both rads or two outlets. I used some small rubber vacum line plug offs and put two zip ties on it as a hose clamp seemed too bulky. The vac caps were not as thick or heavy duty as I would have liked but we will see how they hold up under pressure. Not entirely sure but I assume that small 1/4" nipple I plugged was the "blocking off the bypass line" as recommended above. I plan to pack a few extra vac caps and zip ties incase I have a blow out.

 

[code4]

I ended up using a short piece of 1/2" heater hose (2-3" at most) onto the Stat nipple (Bypass nippple )then plugged the other end with a brass 1/2 pex plug. Finished very nice, using the smallest hose clamps I could find. Better clamps to use if you can find them, are corbin style.

 

[summitboy]

The CR500 has two outlets on the top of the head. That is why some of the installs ive seen have two stats. I think that Bob setup may be the ticket for keeping these bikes in the higher temps. May need two of them for the CR. The Bob is a 90 degree stat vs the KTM 55 and 70 degree stats.

Randy have you spoken with the Bob guy ? I know you said the 70C stat keeps your bike in the 130-150 range. Would a 80C stat be more what we are looking for ? 90 may be a little high no ?

Flow is usually from pump to head out the top to top of rad and then out the bottom to pump i believe. I think LOL

 

[mtn-doo]

Okay, I see your situation. I guess you would need two then. I have not talked to the thermo-bob guy yet. I feel the 90C will be great for 4 strokes. The 2 stroke sled thermostat's I researched are 130F. The 2 strokes prefer cooler running temps than the 4's do. The 70C put's my KX right on the money, from about 120 to 150. I am going to leave it there. When a 2 stroke get's hot, you get that "fade" on the top end. I wouldn't go to hot. We don't have a valve train and upper cylinder oil etc to be conserned with. I feel the 130 to 150 range is just right. Do some sled thermostat research. Let me know what you find? I found two. Ski Doo 800R and Polaris were 130F

 

[summitboy]

I'd like to put twin 70's in but my housings have 55's. Not sure if the 70 from KTM is the same size or not. Will have to see.

The Bob guy says he has sold some 180's (80C) to snowbike guys. I was hoping he would have a 70 LOL. Maybe i will get lucky and the 70 will be the same size as the 55 ??

130 should be the minimum imo. 130-150 like you have is a great range. That stat you have just wont work for my setup. Either need to change stats in my housings or ThermoBob down to 70ish.

Does your KTM housing have bypass or just the bypass built into the tstat rim ?

 

[mtn-doo]

I'd like to put twin 70's in but my housings have 55's. Not sure if the 70 from KTM is the same size or not. Will have to see.

The Bob guy says he has sold some 180's (80C) to snowbike guys. I was hoping he would have a 70 LOL. Maybe i will get lucky and the 70 will be the same size as the 55 ??

130 should be the minimum imo. 130-150 like you have is a great range. That stat you have just wont work for my setup. Either need to change stats in my housings or ThermoBob down to 70ish.

Does your KTM housing have bypass or just the bypass built into the tstat rim ?

It has the small by-pass out the side. I blocked it with a rubber cap.

 

[carbondaddy]

I have been running a ktm 70 degree stat inline in the right hand radiator most of the year in my cr5. For the most part, when the air temps were below about -5C, my temps were good and the bike consistant. This past weekend the air temps were around 0C and the motor would heat up and loose power. I'm considering removing the t-stat and installing a manual ball valve and control the one radiator flow manually

 

[summitboy]

Craig, do you monitor coolant temp with a gauge ? If the bike is getting too hot that tstat should be wide open allowing full cooling. Is the MH capable of building that much load it can't be shed ? Could it be a jetting issue ? Also by running one tstat on the CR500 you are restricting flow in the system until T stat is wide open no ?

I have heard of guys with 450's doing pulls with the fan on which would mean a high engine temp (somewhere in the 200F range to switch fan on). That is obviously a 4 stroke

Randy where do your temps of 130-150F come from, from a ambient temp point of view ? So u have no bypass in yours ? The interesting thing about bypass is it allows your engine to stay in that range more consistently as compared to the up and down of the tstat blocking flow and introducing a cooler influx of water on the cylinder. It's kinda a vicious cycle

Interesting. If you get a chance to read Bob guys testing it is enlightening. He has some great test data to back up his product. I just find his stat a little warm for what I'm trying to achieve.

 

[mtn-doo]

Randy where do your temps of 130-150F come from, from a ambient temp point of view ? So u have no bypass in yours ? The interesting thing about bypass is it allows your engine to stay in that range more consistently as compared to the up and down of the tstat blocking flow and introducing a cooler influx of water on the cylinder. It's kinda a vicious cycle

Interesting. If you get a chance to read Bob guys testing it is enlightening. He has some great test data to back up his product. I just find his stat a little warm for what I'm trying to achieve.

My temps from the Trail Tec gauge stay between 130F and 150F with all different ambient temps. A couple weeks ago at 12 above zero in deep pow and yesterday at 30F and very little loose snow to splash against the cylinder. They have been very consistent. I blocked the bypass. Last year testing that unit, we found the circulation through the by-pass was enough to cool the engine and the stat would not open. Temps would stay in the 80F to 110F range. We blocked the by-pass and it solved the problem. You will not get hot/cold cycles. The stat will slowly crack open allowing a small flow when needed, then modulate further open as temps rise, then modulate flow to maintain temp. It is a temp/pressure assembly. It does not just open or close. It also has a small hole in the stat for circulation. If you pull it out you will see it. Also you can verify flow when it is closed, "cold", by taking your radiator cap off and starting the cold motor. You will see a small flow with it closed, through the tiny hole in the stat, then as temps hit 160F it is full open and a full flow.

I agree, the "bob" set up is to hot for a two stroke. I think they would be perfect for an EFI four stroke though. They need to be n the 190/200 range.

 

[summitboy]

Randy with your setup you see temps from 130-150 range. Is that during normal riding ? Or stop and go riding ?

I see the Bob guys research shows the 20-30 F fluctuation with a normal non bypass system and then with his bypass setup reduces that to 10F. Maybe this is the hot cold cycle I am referring to ? His graphs show a much more consistent temp across the stop and go, speed change testing he did with a proper sized bypass as compared to a open/close tstat system like his test unit has (similar to the way some of MH setups run).

His bypass seems a little smaller than some of the tstats I see on some of the atv/bike setups I see. Just interesting food for thought. He would need a 70 stat for it to work on the 500's IMO to keep it in the 150 range.

Another thing that is interesting is his 190 stat keeps his test unit at 190 all the way through his testing where as a 160 non bypass really fluctuates from 90 to 140 and never really achieves 160. This is all due to bypass.

Here is a link to his PDF

http://www.watt-man.com/uploads/TB_Testing.pdf

 

[mtn-doo]

My 130/150 range is in stop and go boondocking. Those quick stop and go sessions. During steady riding I am around 150 consistent.

That thermo bob set up is very very good looking. Lot's of testing and info. That steady 190F set-up would be perfect for 4 strokes. wow. If he
can make the same set-up with a 160F for 2 strokes, that would be super nice. Thanks