Does anyone use a thermostat on Wr 426? In cold temps. engine runs cooler.I'm talking 32 and below. I searched for inline T-stats that fit in radiator hoses, with little luck. I've seen KTM uses them on some bikes.

Dirt Bike or Dirt Rider had an article a while back about covering 1 radiator with something to block the airflow.

Any info. about T-stat would help.


KTM and Husaberg have one that fits.

Timo Mc

Dont forget to get heat to the carb from the engine. Carbs like to ice up real bad when riding in cold weather. :thumbsup:

this is something i have always hated also ( running the little motors to cold)

in the cold season here, 50 to 70 range , i will always have one whole radiator blocked off with duct tape,

and i can generally get the cooling system up to 200 in the rad ,( 210 in the head )

without the tape the poor thing runs 140 or so which is way to cold and not good for any motor,

i have been trail riding in moab and utah and it was cold as hell,

i had only 1/2 of one radiator flowing air and that seemed to be about correct ,

if i was just a single track or trail guy i would install a thermostat system on my bikes ,

the things work really well about 230 in the heads and 210 in the rad :thumbsup:

I'm looking for info about this as well, especially since it has been so. damn. cold. in Colorado this last week.

Anybody finding a link to one of these inline t-stats please post it here.


Honda XR 650's have a thermostat try that?

Maybe Indy can shed some light on this, but I dont think there is a bypass water circuit on our bikes like there is on a car engine. If a thermostat is installed in-line in a hose, then it will totally block water flow forever. And if the water flow is blocked off, it will never circulate through the head and the hot coolant will never get to the thermostat to open it up.

Better off to block off a radiator with cardboard or duct tape.

Thermostat would be at waterpump outlet side. Hot coolant would be pushed against it.

Bypass has me questioning if its needed or not. I agree all coolant flow would stop when T-stat is closed. But for how long, before it got hot enough to open.

A small by pass could be added before T-stat, MAYBE. Hose is short at pump outlet.

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