getting temps up

[JustAnewb]

So I have been out on 2 rides now and both times I am having trouble getting temps up to 180+. I have PST jacket, Tstat, heated bars and Obie skid plate. I am seeing temps around 130 to 160 but we have been riding mostly in powder. If I let the bike sit and idle it will hit the 180 mark but as soon as I take off it drops. I am wondering if blocking off my rads would help but if the Tstat is closed it shouldn't matter, right? I have tried closing off the heated bars but didn't make a difference. Any ideas? I tore a muscle last ride and am out a few weeks. Of course it's now dumping feet of snow but oh well, going to concentrate on making the bike run better.

 

[wwillf01]

100 percent block the radiators it's good for 30 degrees on my bike to 80 degrees... also make sure the rear of your engine is blocked off from snow.

Sent from my SM-F900U using Tapatalk

 

[jrlastofthebreed]

So the T stat only stops 90 percent of the coolant. So the radiators are still loosing heat. Also the air flowing through then blows on the engine. I also make a guard on to cover the back of the engine from snow off the track.

 

[JustAnewb]

I've noticed that there is always snow packed against the intake and back of the engine. time to fabricate a block off. Any ideas on blocking the rads? I have trail tech aluminum guards

 

[Chadx]

I'll third that. We simply must block off radiators when in deep powder if you want to get your temps up. Some even put a shutoff valve on the bottom hose of the left radiator. Also agree with covering the back of your engine and also any other part you can (bottom of engine between it and skidplate with appropriately sized closed cell foam).

 

[Chadx]

... Any ideas on blocking the rads? I have trail tech aluminum guards

Some use hard plastic and some use flexible plastic fabric. Anything will do. I recommend the cover being on the outside of your radiator guards. Some like the inside. I've tried both and what I found is, if you're blocking plastic is inserted between the radiator guard and radiator, the radiator guard will clog with snow and ice and then when you remove the covers because need to flow air (when back on the trail), the clogged guards won't flow enough air.

 

[jrlastofthebreed]

far as matereal there are threads on here for that. Racecar plastic. plastic signs, kids sleds, It all works. I used signs for 3 years and upgraded to a roll of 1/8" thick black racecar plastic. Looks nicer and costs $30

 

[teal_210]

Blocking off the back of the motor helps a ton. Also put some insulation between your skid plate and motor. I also have insulation behind all areas of my sxs snow shield. What I used was sort of like a pool noodle - something flexible and doesn't absorb water. These two things helped a ton to keep temps consistent. Before it was normal to see 60-80 degrees even with both radiators blocked. After the lowest I see is 120-130.

 

[JustAnewb]

Starting to gather new parts for the bike and I am trying to decide between blocking off the radiators or installing a shut off to the radiators. I ordered a roll of racing plastic and will be molding a shield for the rear of the motor and could use it to block rads or I’ve also looked at a shut off for the rads but thesnowbikeshop is the only place I can find one and it’s outrageous expensive after shipping. Pic is shutoff I’m thinking of using. Thoughts?

 

[Chadx]

Are you talking about both radiators or only one like I'd mentioned earlier in this thread? If you are considering a manual valve to block off all flow to both radiators, I would think it will be a pain to turn that valve off and on manually and it will need to be buried underneath your engine blanket and hard to get to. You have a thermostat and it does this automatically for you. True that many thermostats have internal small hole bypass that lets some hot coolant flow through the radiators all the time, but most of the flow routes through your bypass circuit. The amount of heat pulled out of the coolant by that is very minor compared to snow powder blasting your radiators and onto your engine from all sides. Concentrate on blocking off entire engine and quick covers for your radiators. The other thing to consider is the thermal shock of opening up that valve when your motor gets really hot but your radiators have been blasted with snow for 20 minutes. True that the bypass circuit would temper that a bit if you have it routed reasonably, but in my opinion, manually turning off both radiators isn't needed or even beneficial and is making a lot of manual work for yourself monitoring temps and manually working a valve. You'd still want to so something to block off the front of the bike or you'll be shoveling snow back into your motor. So just focus blankets for the radiators, motor (front, back, underneath with either homemade, separate units, or a Selkirk unit) and let the thermostat do it's thing.

As mentioned, after doing all the appropriate engine blankets, etc. which are the biggest bang for the buck, some have done a shutoff valve on the return of only one radiator but that would be in addition to your engine blankets and radiators being blocked. I've seen guys do that for those numberplate-deep days when even radiator guards and engine blankets can't keep temps up. With that setup, one radiator flows nothing (usually left one) and the right one (with filler cap) can act normally (though both are blocked off with radiator covers) and you won't have to mess with that valve except for the trail ride out and ride back. That valve is not very common and kind of an extreme thing for extreme days and for when you've done all the other things. and still need more heat retention. It's pretty rare conditions that anyone needs to go that far to keep temps up.

 

[dooman92]

Justanewb, the valve you are considering would definitely raise temps, but very quickly and would require rapidly opening the valve in any engine load situation. With a thermostat completely closed, we still have a high percentage of cooling capacity because the cold coolant (radiators cold) will fall from the rad and warm coolant (from engine) will rise into the bottom of cold rad via bottom hose. This is called convection and is very effective. If you close this off with the valve the engine will warm rapidly. I considered a similar setup but decided turning that valve on and off would be a PIA and not able to do quickly and didn't like the cold shock issue either.

Good ideas in above posts. Controling the temp of the rads with coverings has been the most effective measure I have used, but on those headlight deep light snow days even completely covered rads don't keep temps up and some method of protecting the engine block from getting snow washed is necessary.

 

[JustAnewb]

Thanks for the replies. I will be looking at materials to block rads. I may start with race car plastic but I think something with more flex will be easier. Back to google.

 

[eric82930]

Carbed bikes run fine all day at 130-160. If you want to just avoid the issue you can measure your coolant sensor when it's at about 170 and buy a 10 cent resistor of the same value then install a double pole switch so after a cold start flip the switch to use the resistor instead of the sensor.

 

[needpowder]

Thanks for the replies. I will be looking at materials to block rads. I may start with race car plastic but I think something with more flex will be easier. Back to google.

As mentioned, race car plastic works just fine. This has been working well for me.

Radiator covers YZ 450

I have found that covering my radiators with a removable piece of plastic is just as effective as an engine blanket. On super deep cold days the engine blanket is not enough and I need to cover one or both radiators— at least some of the time. It is nice to have removable/adjustable radiator...

www.snowest.com

 

[mortimis]

Not to hijack the thread, but am curious-- I'm running engine jackets, coolant heated bars, t-stat, etc, should I be getting some basic radiator blockers too? I've seen some that people have taken material (like Flying Carpet or similar material) and either putting them in between the louvers and radiators themselves, or rigging them to sit over the radiator louvers themselves. Any recommendations? TIA.

 

[Chadx]

Yes, you should also have removable radiator covers as well. Typically, you'll run without them on the trail and set up snow and with them on in deep powder. Hard plastic ones work and can be stored pretty easy since they are only radiator sized. Some prefer the cover to slide between the radiator guard (or stock plastic lovers) and the radiator. They secure well there.

I ran them that way on my first snowbike and it worked fairly good, but found that snow and ice would build up on the radiator guard and then when I needed the cooling and removed the covers, the ice buildup on the radiator guards hampered airflow to the radiator. So I started using radiator covers that sat outside (in front) of the radiator guard. You can do this with hard plastic or flexible material. I found a flexible material and did a sort of one piece bib on the next snowbike. It worked great as it covered the entire front of the bike left to right, shroud to shroud. If I wanted a bit of exposure/flow, I would fold down the top edge on one or both sides of the bib and expose the upper portion of the radiators but still keep them mostly still protected from snow blast. This bib prevented all ice build up and was very effective at blocking cold air and snow. That bib, along with a retail engine blanket and homemade rear engine blanket made from the same bib material, proved to work great and engine temps stayed up.

The next build, and my latest, is similarly protected and complete in coverage, but this build I started with Selkirk engine cover. I used 1/4 thick, closed cell foam sheet to go under engine between engine and skid plate touching the engine (this is a yamaha so selkirk heat exchanger is up front rather than below engine like for other bike brands). Ran the same foam from under the engine up behind the engine to block and insulate from the rear plus a yeti enclosed tunnel throws less snow. On previous kits, in addition to blanket on the rear of the engine, I blocked the top front of the tunnel to stop snow from being thrown up.

The Selkirk has a removable radiator shield panel, but they are screened towards the top so I used the same flexible material as my previous bib to create a shroud-to-shroud bib that is held in place by the removable Selkirk radiator partial covers. This bib lays all the way up the front of the radiators and back across the top of the radiators. Great coverage and I have 3 levels of coverage to choose from: Run with all of it in place, remove only the bib or also remove the Selkirk radiator panel to get a lot of airflow and exposure. Works great. I run 170 F. to 190 F. most deep powder days. I have a 194 F. (90 C.) C3 thermostat which starts to open around 188 - 190 F. I'll only hit above 194 F. on low speed trail work or long steep uphill pulls. With radiators uncovered and on the trail, if temps creep up over 200 F., I speed up. Anything over about 20 mph will bring my temps back down and keep them there.

For me, the key has been wrapping, blocking, covering as much as possible. Then, other than covering or uncovering the radiators for the day's conditions, the thermostat and radiators do their job without much drama. Would be even better with tunnel cooler replacing one of the radiators.

 

[POLZIN]

I made some block offs from 1/8 rubber sheet and used some snap buttons to hold them to the rad guards i can just pop then on/off in seconds. Would work with just about any rubber or plastic sheet.

 

[needpowder]

Not to hijack the thread, but am curious-- I'm running engine jackets, coolant heated bars, t-stat, etc, should I be getting some basic radiator blockers too? I've seen some that people have taken material (like Flying Carpet or similar material) and either putting them in between the louvers and radiators themselves, or rigging them to sit over the radiator louvers themselves. Any recommendations? TIA.

Short answer, yes. You will see a huge difference in temperatures

 

[Chadx]

By the way, this is flexible material I use for bibs, etc. Pretty good stuff. Will melt directly on exhaust pipe, but not against pipe guard, radiators, coolant hoses, etc. It's been pretty handy to have around the house for other things as well. And it takes grommets well (I folded and doubled up the edge for that project, but seems like it would hold a grommet single ply as well if there wasn't too much pressure on it). It will start to get a bit more stiff as the temp drops but still plenty flexible. "Cold crack" rating is -30 Degrees F.

Search for:
18 oz/61" Industrial Coated Vinyl with Fire Retardant - BLACK

I bought from Big Duck Canvas but available from many sources.

 

[CATSLEDMAN1]

To get your engine to run nicely at 190 in deep powder you have to cover any area of the motor that loose snow can contact aluminum engine cases/head/cyl etc. In sifting cold grainy powder your 190 thermostat doesn't work because your coolant temps never reach 190 so it makes no difference if you have a thermostat or not.

Attention to detail here. Go over your motor methodically covering ALL exposed engine cases.

The last 5 or 6 years I have always run a heat exchanger with right side radiator just to use to fill the system. I only really achieved constant engine temps when I finally ditched my totally encosed in foam right radiator. You will know when you finally get good heat control when your engine temps just stay at 186 or 193 or 182, never seen a thermo bob thermostat actually run right at 190.