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Low operating temperatures

Posted on a similar thread, here is some further thoughts that might help.

Hey -------, where is your temp sensor located? Some will use the rad fin style sensor which, while accurate for rad temp, is not accurate for engine temp. The reason is that if the thermostat is closed which it will be often in the powder, the coolant flow is shut off to the rads. When this occurs the rads cool right off and your temp sensor would indicate a very cold condition. Once the tstat opens the rad temp will start to rise but as the cold coolant goes back into the motor the tstat will close and the cycle continues. A much better option is to use the probe style temp sensor that goes into the tstat body on the engine side of the tstat. It will be accurate to the actual engine temp. Same flaw in the rad cap style temp gauges. When there was no tstat in the bike this was not an issue (summer use) but now that we have added tstat's this is a different situation.
Getting consistent temps is a challenge as stated above. Over the last few years of snowbiking this is where I have focused my time and have evolved my engine cover and rad blocking solutions to the point that I finally have good consistent temps in most all conditions. It does require monitoring temps and cycling rad blockers as needed but that is it. I now run all day in the 180-200F range and the bike performs best in this range. Most power, no overfueling, no moisture in the oil.
I started with home made engine blankets, hand made hard snow shields, common industry available engine blankets, pretty much tried them all. Some work better than others for sure and there are some great products out there. In pursuit of my own solutions I soon realized that complete closure was where I started to have great results. The cooling system on the bikes using the just the radiators is more than sufficient to keep the engine cool as long as they can flow air when they need to. I have seen many riders who ride in the powder, bike runs cold, then they get to the trail and the bike overheats. This is because the rads are iced over and air cannot flow through them. I see guys peeling off engine blankets, etc. thinking they are the cause of the overheat. Keeping the rads blocked and clear in the powder and then removing one or both blockers on the trail or in low snow conditions is the answer.
I have developed an engine cover that has been working fantastic and provides complete engine coverage, full frontal closure when needed, and gives tremendous access for service and repairs. I have been building them steady and refining the design over the last couple seasons to the point I am ready to hit the market. (soon) So far I haven't needed to, I can barely keep up as it is. You can see them in much more detail on my FB page, link in sig below. Here is a couple pics of the latest evolution.


IMG_2331.jpgIMG_7932.jpgIMG_7935.jpg
 
My riding partner and I are riding same bike. Over the years we found out in 3rd gear cold powder we had to:
Close all air gaps on the front of our bikes
make a good guard to keep snow from track off back of engine and put thick foam back there on the engine, 30 degree difference on many days just with this mod.
4th and 5th gear on 12" of new snow on trails our bike would run 145 degrees/190 thermostat
Covered the back of our engines, right up to 180 to 190 same trail same conditions next day
5 years ago we ditched radiators and run heat exchanges because even blocked radiators bleed toooo much heat
many cold days in deep snow my ktm500 is operating strickly off handlebars and engine heat loss, I feel my heat exchangers and they aren't even melting the snow off them, yet my bike is 180 degrees and I have to run only 1/3 on my handlebar valve.
I did this last year . Even ditched the radiators completely works great always run 180-190 in any conditions.
 
2018 YZ450. I didn't have one side of my engine blankets finished so I rode 6 days without it. The bike will cool off but rarely goes much below 160. Usually its sitting between 170 and 180, 190+ on the trail using a 190 thermostat. Normally I only block off the one radiator. I'm running my bars off the bypass and they are smokin hot. The tune on my 18 is quite a bit leaner in the midrange than the tune on my Tbob 2011 YZ which may help the motor build heat. My 2011 hangs around 150 or a bit lower with skid plate, rads blocked and blankets and it has a 176 thermostat. I'm going to lean out the midrange of the 2011 and see what happens. The 190 thermostat is the answer at least for Yamaha IMO. The C3 part for the Yamaha is a slick piece, I'm not familiar with their KTM part.
Hi there, I’m new to snow biking and am looking at swapping out the thermo bob on the 2016 yz450f for the C3 set up with they heated bars . Curious what the best thermostat for the bike is, sounds like 190 from what I’ve read. Also what are you doing for tuning, I ordered a gytr tuner so I can adjust it myself heard lots of guys turning down the fuel and cranking up the ignition. Any advice is appreciated thanks.
 
Egenge98, something to consider. The cylinder on the yami heats a bit different because cold air and potentially snow are cooling the front of the cylinder while the back runs much warmer given exhaust discharge and more protected from cooling. That causes a distortion of the cylinder that resulted in power loss. Somewhere I learned that yami programmed the ecu to back off power/timing? at about 180ish in response to this issue. They also had the rad fan programmed to come on at 170. I rode a 17 450fx for several years. Two buddies rode 16 450fx's. The bikes had stock ecu's and similar and same kits. We tested this theory on several occasions. The bike that was running under 180 was always slightly stronger than the one at 200ish. This was sided by side on a trail or open run with both bikes loaded same. I am general an advocate of 190-200 as operating temp. My two 500ktms both run stronger at 200 than at 170, but the yami was just the opposite. So, I used the 176f thermo in my thermobob for that bike. I think C3 has similar option. In my experience no negative to the 190 in the yami other than a possible slight power reduction when really warm. Fwiw.
 
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