• Don't miss out on all the fun! Register on our forums to post and have added features! Membership levels include a FREE membership tier.

Thermostat

KAWGRN

Well-known member
Premium Member
Nov 26, 2007
2,522
394
83
everywhere
Here is what a ice racer from Sweden uses on his 500. He uses twin 55C stats. I think it will be to cold. I am in the process of fitting twin 70C stats in my 500. Would be more or less the same as what MtnDoo ran on his KX500 with no bypass. Gonna try it and see what i get. I still like Thermobobs idea and i think with a 1/4 bypass line it will work well. Still waiting for a good size housing from him though for a 70C. The 195F housing he currently has is to big imo.

2m7i1oo.jpg

Thats the stat Im planning on using in conjuction with my KTM bypassing stat, but Im going to use the single direction in the outlet side on the second radiator, this is on my 570 berg.
 

summitboy

Well-known member
Premium Member
Nov 26, 2007
2,146
851
113
90c just give him a call he can answer question he's been dealing with lots of snowbike guys lately

I've been talking to him lots. He is machining a new housing for a 70C stat for the 2 stroke crowd. I just need him to make the housing smaller. That 90C stat is a monster housing.

KAWGRN are you going to run the 55C in your berg ? That will prob be too cold. I think Thermobobs 90C stat is the answer to the 4 stroke imo. Consistent and hot ! However in the deep powder it seems some cant get the temps up which makes me think the bypass may be a little big. Guys will have to test them a little more.
 
Last edited:

scooter4x40

New member
Lifetime Membership
Oct 10, 2010
30
2
8
Alberta
Do you think a small ball valve choked back would work as we do that on jet boats to keep temp up in cold rivers.

Thanks
 
S

snowboatboy

New member
Oct 22, 2011
138
4
18
Petersburg Ak.
I have a cr500 and I'm planning to put a valve on the lefthand rad. and leave the stat with bypass on the righthand rad. I think that this with a temp gauge will be pretty effective. I'm looking for the best valve, small and compact, light.

I have a KTM stat now but it's in the way for putting a large desert tank on so i'm attempting to reposition it.
 
Last edited:

summitboy

Well-known member
Premium Member
Nov 26, 2007
2,146
851
113
I have a cr500 and I'm planning to put a valve on the lefthand rad. and leave the stat with bypass on the righthand rad. I think that this with a temp gauge will be pretty effective. I'm looking for the best valve, small and compact, light.

I have a KTM stat now but it's in the way for putting a large desert tank on so i'm attempting to reposition it.

Which stat do you have now on your CR ? Pics ? You say its a KTM ? 55C ?

Sad news, the KTM 70C stats do not fit the KTM 55C housings. Booh

Still waiting to see what Thermobob has for a final size. The current ones are huge. I think he said he could get down to 2.0" width/diameter.
 

J&L Snowhawk

Well-known member
Lifetime Membership
Jan 3, 2008
1,269
288
83
Aberdeen, SD
stores.ebay.com
What thermostat is this

Where do you buy this thermostat



Here is what a ice racer from Sweden uses on his 500. He uses twin 55C stats. I think it will be to cold. I am in the process of fitting twin 70C stats in my 500. Would be more or less the same as what MtnDoo ran on his KX500 with no bypass. Gonna try it and see what i get. I still like Thermobobs idea and i think with a 1/4 bypass line it will work well. Still waiting for a good size housing from him though for a 70C. The 195F housing he currently has is to big imo.

2m7i1oo.jpg
 

summitboy

Well-known member
Premium Member
Nov 26, 2007
2,146
851
113
They are off a KTM 380SX. They fit a number of different bikes. They are 55C stats. I may have two units for sale. I need 70C. Will know this week. Cheers
 

dooman92

Well-known member
Lifetime Membership
Mar 1, 2010
742
238
43
thermo

Anyone come up with additional options for thermostats and maintaining temps?
 

phatties super shop

Member
Lifetime Membership
Premium Member
Dec 6, 2008
44
9
8
If you have a Kawasaki use a Kawasaki Racing thermostat. If you have a KTM, Yamaha or Honda use the Trail Tech thermostat.
 

dooman92

Well-known member
Lifetime Membership
Mar 1, 2010
742
238
43
thermo options

Phatties super shop, I appreciate the info. I am looking for a husky setup. I could not locate the trail tech thermostat set up. I did find the thermo delete for ktm and the trail tech inline temp sensor t, but no housing with thermostat from trail tech. Would you have a link? Thanks
 

summitboy

Well-known member
Premium Member
Nov 26, 2007
2,146
851
113
I think a lot of guys mistake the TT thermostat delete for a thermostat. Ill post a pic of the new 70C Thermobob once i get them.
 
I have KTM thermostats on my 2012 KX 450’s and all I can get them up to in the deep snow is 120o max, most of the time they are under that. I think I am going to try pinching off the hoses on one of the rads. If that does not work I am going to eliminate the by pass on the thermostat housing and drill a very small hole in the thermostat so the hot water will reach it so it will open when up to temp.

Allen

Allen, are you still using the KTM t-stats? Did you drill a bypass hole in them?

Just curious as to what you've been doing to maintain temps on the demo fleet.
 
M

mtn-doo

Well-known member
Feb 26, 2004
1,315
661
113
Kalispell, Mt
Allen, are you still using the KTM t-stats? Did you drill a bypass hole in them?

Just curious as to what you've been doing to maintain temps on the demo fleet.

We did a lot of testing with the KTM stat in the beginning. With the re-circ used, it is enough recirculating through the cold case that the temps never get up much. The stat will almost never open. We got a coolant plug from NAPA and plugged the recirc nipple. Next we took off the radiator cap to watch the return line entering the top of the rad. Started the bike in the shop and let it idle. Observing the return line entering the rad, there was a small trickle of coolant flow. After the thermostat reached approx 170F the stat opened and had full flow. We disassembled the housing and found they have a small vent hole drilled in them which allowed the small amount to flow through. Running this way helped temps a bunch but still not enough I feel.

I did some research on the 450F motor testing, and the specific tests were to be done at an oil temp of 190F. That made me come to the conclusion they dial that motor for a 190F operating temp. That would be ideal. Hard to get those temps in the snow, but blocking the recirc nipple bumps you up into the 130 to 160 range. When the stat opens, you will get a surge of cool water and a momentary drop, but average in the 130/160 range.
 

summitboy

Well-known member
Premium Member
Nov 26, 2007
2,146
851
113
One thing to take into account here is we typically measure the temp at the head exit (outlet). If you run the bypass you get a overall constant temp in the motor albeit lower than we would like. I'm not sure what the best temp situation is for the motors. Hot exit and cold inlet or warm exit and warm inlet.

I talked to Bill at Thermobob at great length about this and dwell time. He said running no bypass and getting the temp up at the outlet is really just making us feel better LOL. The inlet temp is lower than outlet with no bypass, more constant overall with a bypass. The problem with the snowbikes is they obviously seem to get too much cooling when in the fluff. Running a larger stat (2 stroke) helps but you can only go so far and then you may be to hot in other situations.

Seems like the 70C works well on the 500 as per MtnDoo's KX and maybe a 90C would work better on the 4 stroke machines. The KTM 4 stroke bikes run the 70C. May not be enough.

I am going to split the bypass and run a smaller 1/4 bypass to start and see how it fares. If no likey then i will cap the bypass and run it that way. If i could be in the 110C to 130C with bypass that would be perfect on the 500. Kinda doubt it though. Im bettin 90-110 with bypass will be reality.
 
Last edited:
M

mtn-doo

Well-known member
Feb 26, 2004
1,315
661
113
Kalispell, Mt
Chris, When you get the smaller housing being built, will the 90C stat fit the smaller housing? If so, I will be trying that on the SXF with a "small" bypass. Something like a 1/8 bypass with the 90C may be ideal for the thumpers.
 
Premium Features