M
Hmm kinda a bummer hearing about temps. What about slightly closing down the bypass valve?
Selkirk Engine Armor
- Thread starter Chadx
- Start date
A
I dont think you can close up the bypass valve, as it would cause the water pump to struggle. I feel like you need proper flow.
M
I thought u could neck it down during real cold temps but maybe ur right and i miss understood marc when i chatted at him awhile back
Reducing, or even closing, the bypass circuit is an option. Deadheading will not hurt this type of waterpump. But most thermostats have bleed holes anyway so even if the bypass is completely closed off, you are not truly deadheaded. Somewhat a concern is thermal shock, meaning your thermostat opens and 100% icy coolant hits your hot motor, but the bleed hole is already caring for that to an extent. And we are already blasting our hot engines with snow. And if the coolant coming out of the head is hot, the thermostat opens and coolant circulates freely and cools your engine.
For heated bars, you typically wouldn't completely close off the bypass circuit anyway. For the heat exchanger, you might. Still not much of a concern (FAQs regarding deadheading on the C3 website explain this), but if you are still concerned, Selkirk sells valves that you could plumb to bypass the heat exchanger, as needed, with a valve so you can tailor how much is going to the heat exchanger and how much is straight bypass (and/or handlebars).
For heated bars, you typically wouldn't completely close off the bypass circuit anyway. For the heat exchanger, you might. Still not much of a concern (FAQs regarding deadheading on the C3 website explain this), but if you are still concerned, Selkirk sells valves that you could plumb to bypass the heat exchanger, as needed, with a valve so you can tailor how much is going to the heat exchanger and how much is straight bypass (and/or handlebars).
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M
Thanks ChadX for the info!! U know ur stuff!!
A
Good info - thanks Chad.
Chadx, fwiw, I found the Yamaha runs a little stronger if temps are kept under 200. Apparently because the rear of the cylinder (exhaust side) runs hotter than the intake (front side) which gets more air and snow exposure causing a bit of cylinder distortion that results in power reduction. I tested this theory several times over two seasons when my buddy and I both had 450fx's. We raced several times, the bike that was at 170ish would beat the bike that was at 200 or better. The same bike was not always the fastest. It was the one that was running a bit cooler if the other was pushing 200. Both had stock ecu so Yamaha might make adjustments to help lower temps as the temps get near 200.
Im not familiar with the Selkirk system and how well it insulates the rads from air and snow, it looks good in photos. If the radiators get enough snow or air to stay cool the engine will run cool. With the thermostat closed and no coolant being pumped by the pump, convection alone will cool the engine. The cold coolant in the radiator will fall into the engine case and warm coolant will rise into rads via the lower rad hoses. Also, the thermobob bypasses (a lot) enough coolant when added to convection would create reduced temps. Unfortunately, that bypass coolant is not regulated by the thermostat so cold coolant from that heat exchanger is constantly sucking heat out of the engine. I bet reducing the volume of the bypass will help. I agree regarding the bleed hole and deadheading the pump.
I ran all day on Sunday with a constant bath of snow on the case and the front of the bike. I had the rads covered 90% all day. I saw 180 a few times but mostly 160-170. All cooling was by convection and coolant thru bars as my 195 thermostat never opened all day. Little or no convection movement with a tunnel cooler, much better control as coolant flows thru thermostat not convection, thats why they work better.
Im not familiar with the Selkirk system and how well it insulates the rads from air and snow, it looks good in photos. If the radiators get enough snow or air to stay cool the engine will run cool. With the thermostat closed and no coolant being pumped by the pump, convection alone will cool the engine. The cold coolant in the radiator will fall into the engine case and warm coolant will rise into rads via the lower rad hoses. Also, the thermobob bypasses (a lot) enough coolant when added to convection would create reduced temps. Unfortunately, that bypass coolant is not regulated by the thermostat so cold coolant from that heat exchanger is constantly sucking heat out of the engine. I bet reducing the volume of the bypass will help. I agree regarding the bleed hole and deadheading the pump.
I ran all day on Sunday with a constant bath of snow on the case and the front of the bike. I had the rads covered 90% all day. I saw 180 a few times but mostly 160-170. All cooling was by convection and coolant thru bars as my 195 thermostat never opened all day. Little or no convection movement with a tunnel cooler, much better control as coolant flows thru thermostat not convection, thats why they work better.
Dooman,
Great insight regarding the yamys preferred temps. I can't imagine the bike running up to or over 200 when offtrail so no worries, but very interesting nonetheless. Even on trail when moving slow, I'd see the temps creep up to 194 or so and then my C3 thermostat opening would bring it back down to 190 or 191, then slowly back up to 193. I think I only saw temps over 193 a couple times; Once in very slow mogul-from-hell trail section and one time idling and not paying attention.
Your point about the radiators is spot on, hence my desire to have the ability to cover them completely like in my previous builds. The current selkirk setup does not have that capability so I'm working towards a solution there. Covering the radiators is a higher priority than sealing up the grates in the side of the selkirk. Looking at the bike tonight, it may be important to have at least some grated section on the upper sidepanels so air has some way to push out to increase radiator flow on the trail, but I noticed a fair amount of snow entering through the current side grates so reducing the grated area will help. The unregulated bypass circuit, as you mention, is the main suspect with the current setup's low temps. MTNMOTOs experiment of disconnecting the heat exchanger and engine temps running at in a much warmer range is further evidence.
Tunnel cooler cooling was my intent for this new build but for 2020, the Yeti can no longer use the C3 tunnelcooler as they could from 2019 on back to the early kits. 2020 has new aluminum bracing in the area where the C3 tunnel cooler would occupy. It was quite disappointing.
I'm trying to be open to the intended design of the selkirk, though the logical part of my brain still needs convincing as to why the heat exchanger is on the bypass circuit rather than the open-thermostat circuit. I am entertaining myself with alternative plumbing designs in my mind should I decide to replumb with the heat exchanger on the thermostat circuit rather than the bypass one.
Great insight regarding the yamys preferred temps. I can't imagine the bike running up to or over 200 when offtrail so no worries, but very interesting nonetheless. Even on trail when moving slow, I'd see the temps creep up to 194 or so and then my C3 thermostat opening would bring it back down to 190 or 191, then slowly back up to 193. I think I only saw temps over 193 a couple times; Once in very slow mogul-from-hell trail section and one time idling and not paying attention.
Your point about the radiators is spot on, hence my desire to have the ability to cover them completely like in my previous builds. The current selkirk setup does not have that capability so I'm working towards a solution there. Covering the radiators is a higher priority than sealing up the grates in the side of the selkirk. Looking at the bike tonight, it may be important to have at least some grated section on the upper sidepanels so air has some way to push out to increase radiator flow on the trail, but I noticed a fair amount of snow entering through the current side grates so reducing the grated area will help. The unregulated bypass circuit, as you mention, is the main suspect with the current setup's low temps. MTNMOTOs experiment of disconnecting the heat exchanger and engine temps running at in a much warmer range is further evidence.
Tunnel cooler cooling was my intent for this new build but for 2020, the Yeti can no longer use the C3 tunnelcooler as they could from 2019 on back to the early kits. 2020 has new aluminum bracing in the area where the C3 tunnel cooler would occupy. It was quite disappointing.
I'm trying to be open to the intended design of the selkirk, though the logical part of my brain still needs convincing as to why the heat exchanger is on the bypass circuit rather than the open-thermostat circuit. I am entertaining myself with alternative plumbing designs in my mind should I decide to replumb with the heat exchanger on the thermostat circuit rather than the bypass one.
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So the time has come, my Selkirk Kit is sitting in the garage waiting to be installed. I’m kinda on the fence about just going back to blanket ....
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Sent from my iPhone using Tapatalk
I must disagree with closing down the bypass completely. With my first Snowbike builds 10 years ago I talked with Allen and we were having trouble keeping temps up with just the bypass. Mind u we didn’t have slid plates on some and didn’t block radiators back then. I put a pressure gauge on my ktm back then and that little pump could produce dam near 40 psi when deadheaded. You are asking for seal and gasket failures if you deadhead. Ask me how I know...lol. Marc runs the heat exchanger I believe to keep the snow shield ice free and to help keep the oil warm. I ran his shield on a yz450 last year and with all the vents blocked, in deep powder we would have to block the left radiator to keep temps up. On my 20 501 this year I rode at rev in nipple deep powder with the front shield on and bars on full heat and the husky ran 170-180 all day long. I am wondering if the placement of the cooler up front on the yammy is working too good and robbing to much heat. I understand Marc’s thinking of keeping the aluminum shield ice free, but maybe not at the cost of engine temps. I am also running a pr2 Ecu on my husky and though maybe that was keeping temps up, but I had a pr2 on my yammy. One thing I do know is Marc will figure it out.
S
Yamahas run cool, KTM/husky can run hot. We went to slightly smaller vents on the Yamahas this year, will probably go even smaller. We are working on a different style of Yamaha radiator guard/protection/heat shield to replace the ice prone stock plastic. Blocking off the upper 1/3 of rads should increase temps and help ice buildup. Spacing the heat exchanger 1/8 off front of shield will help keep heat in. Seal the gap between lower side panels and frame to keep snow out. Easier to make it warmer than colder.
As for KTM's running cold with Engine Armor, not in our experience. Stuck open thermostat? If running cool, slow airflow, block left side radiator to get temps up, cover left side vents if needed. Let the heat exchanger, thermostat, and cooling system control the temps.
If running hot, run a fan or ride faster! Airflow makes a big difference, slow going will raise temps. Every bike, rider, and thermostat/bar combo runs different. Block or increase airflow to adjust, keep the heat exchanger working.
There is very little coolant in these engines, not much capacity for rapid condition changes.
We will have more block off options as soon as we can get caught up on orders.
Thanks everyone!
As for KTM's running cold with Engine Armor, not in our experience. Stuck open thermostat? If running cool, slow airflow, block left side radiator to get temps up, cover left side vents if needed. Let the heat exchanger, thermostat, and cooling system control the temps.
If running hot, run a fan or ride faster! Airflow makes a big difference, slow going will raise temps. Every bike, rider, and thermostat/bar combo runs different. Block or increase airflow to adjust, keep the heat exchanger working.
There is very little coolant in these engines, not much capacity for rapid condition changes.
We will have more block off options as soon as we can get caught up on orders.
Thanks everyone!
M
Thanks Marc and Monica for the info and especially u guys for great customer service even when u were so busy. Cant wait to get on the snow!
Glad you joined the thread! Top notch!
A
I had my maiden voyage with the selkirk yesterday. Outside temps were around -3c or 27f. After reading this thread I decided to float my heatsink and put some small washers between the skidplate and the heatsink. We had 3ft of blower pow, so it was the perfect day to test with me plowing snow wherever I went, and yet warm temps on the trail up.
All I can says is... WOW it was amazing! It is everything I wanted it to be. Here are the points of interest of the ride:
1. Trail up was groomed and the bike was getting a bit hot, pushing 200+F and forcing me to hop off the trail into the powder wherever possible in order to bring temps down.
2. Once I got to the top in the powder the temps were PERFECT all day. Always 150-170 in the deep powder.
3. An added benefit I noticed is that the engine retains heat a lot better when you stop for a while. Usually it gets quite cold when you stop to dig someone out or have a snack. I would fire up the motor after a wait and be greeted with temps around 120-130 still.
4. Since the only time it was getting hot was on the trail, I wanted to test taking the front rad blocker off and going in powder to see what would happen. To my surprise, the temps were not affected and still hovered between 150 and 170 in the deep stuff.
5. Trail down is always easier on the motor and wont be as hot, but going down the temps were a perfect 170 without that front cover on.
I think I am going to leave that cover off on nice days and experiment with putting it on for those cold days. First ride though, I am thrilled!
All I can says is... WOW it was amazing! It is everything I wanted it to be. Here are the points of interest of the ride:
1. Trail up was groomed and the bike was getting a bit hot, pushing 200+F and forcing me to hop off the trail into the powder wherever possible in order to bring temps down.
2. Once I got to the top in the powder the temps were PERFECT all day. Always 150-170 in the deep powder.
3. An added benefit I noticed is that the engine retains heat a lot better when you stop for a while. Usually it gets quite cold when you stop to dig someone out or have a snack. I would fire up the motor after a wait and be greeted with temps around 120-130 still.
4. Since the only time it was getting hot was on the trail, I wanted to test taking the front rad blocker off and going in powder to see what would happen. To my surprise, the temps were not affected and still hovered between 150 and 170 in the deep stuff.
5. Trail down is always easier on the motor and wont be as hot, but going down the temps were a perfect 170 without that front cover on.
I think I am going to leave that cover off on nice days and experiment with putting it on for those cold days. First ride though, I am thrilled!
0
What Bike are you riding?
A
2014 450SXF Factory edition with a 520 big bore kit. Pictures higher up in this thread.
0
Ok thanks for the report
A
Also, I am not sure if it matters, but I plumbed my bike like this:
Thermobob-> Splitter-> One line to Heated bars/One line to Heat Exchanger-> Both come back to a Y into a single bypass line
Thermobob-> Splitter-> One line to Heated bars/One line to Heat Exchanger-> Both come back to a Y into a single bypass line
Here is the quick and easy radiator cover I incorporated into my Selkirk Engine Armor radiator cover. It's a a fabric that I ordered from Big Duck Canvas years ago and have used for many projects (snowbike radiator covers, rear engine guard and other projects). It takes grommets well, which I did on my previous snowbike bib. Note that it will melt in direct contact with an exhaust pipe, but have not had any issues with melting when fabric is in contact with engine or radiators.
The fabric description is: 18 oz/61" Industrial Coated Vinyl with Fire Retardant
I made this cover a few weeks ago an it has worked great so far (3 rides). Started with a square piece, cut a hole for the Selkirk 1/4 turn fastener to pass through, and installed behind the Selkirk radiator panel using it to hold the fabric in place. Then trimmed to the edges of the radiator guards. On top of each radiaor, I left enough material to simple curve the material backwards over the top of the radiator. It's never flopped forward or moved when riding three different rides. The nice thing about this being on the outside of my radiator guards, rather than between the radiator guards and radiator, is the guards don't clog with ice and snow. So when it's time to remove the fabric and hit the trail, I get full air flow rather than restricted airflow due to ice in radiator guards. It folds easy, even in cold, so I store it as the top layer within my Pelican case. Typically I leave it off for the ride out and off for any short off-trail playing on the way out, then install it once I'll be off-trail the rest of the day. Once back to the trail, pull it off for the ride back to the trailhead.
The fabric description is: 18 oz/61" Industrial Coated Vinyl with Fire Retardant
I made this cover a few weeks ago an it has worked great so far (3 rides). Started with a square piece, cut a hole for the Selkirk 1/4 turn fastener to pass through, and installed behind the Selkirk radiator panel using it to hold the fabric in place. Then trimmed to the edges of the radiator guards. On top of each radiaor, I left enough material to simple curve the material backwards over the top of the radiator. It's never flopped forward or moved when riding three different rides. The nice thing about this being on the outside of my radiator guards, rather than between the radiator guards and radiator, is the guards don't clog with ice and snow. So when it's time to remove the fabric and hit the trail, I get full air flow rather than restricted airflow due to ice in radiator guards. It folds easy, even in cold, so I store it as the top layer within my Pelican case. Typically I leave it off for the ride out and off for any short off-trail playing on the way out, then install it once I'll be off-trail the rest of the day. Once back to the trail, pull it off for the ride back to the trailhead.
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