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18 MC EB overheating

bucky919

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Feb 3, 2008
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North Dakota
Did a trail ride with the wife over the weekend, on a groomed trail and 20+ degrees. Never saw over 132 degrees on the trail and 105ish off trail.
 

boondocker97

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Oct 30, 2008
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Billings MT
Mine has been running on the hot side. For example I rode in 6" of fresh on groomed trail and it runs hot. 14,000 sled and I have to drag my flipping boots to keep it cool.
Damn B.S. if you ask me.
Tar.

You've got an air bubble trapped in the system or something. That is not normal.
 

boondocker97

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Oct 30, 2008
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Billings MT
How has the cooling capacity of the Mtn Cat held up now that we are well into the winter season? Thoughts from others would be appreciated.

I still find my sled getting warmer than I believe is normal considering some of the snow depths/conditions I have been riding in. The sled does very well off trail in the powder, averaging temps in the 110-120 range. On the trail however, that number climbs to 135-145 when cruising at 50-60 mph with several inches of fresh snow sitting on a groomed trail base. Oddly enough, where the trail is tighter and winding through the trees, speeds drop to around 35-40 mph and the temps also drop to around 110. This is the direct opposite of every other sled I’ve owned. Rule of thumb is to speed up to add cooling capacity, but this doesn’t seem to be the case with my Mtn Cat. I believe there is a lean RPM section in the fuel map that increases temperatures in the 6500 rpm range - this is why I’m seeing higher temps at higher rpms.

Has anyone noticed anything similar?

Does anyone have any experience with adding the larger, longer cooler to the 153” chassis? This might be an option I pursue over the summer to make the sled a little more trailable next season. While I understand this is a deep powder sled, there are times where I need to ride 20-40 kms of trail to get to the good stuff.

Historically cats have run a little hot in the midrange with the timing they run. As long as you're staying under 150 degrees I wouldn't worry about it. If you really want the long cooler, get a list together of all the mods you want to do to your sled, and have the parts ready because you'll have it torn down far enough to do them all in one shot.
 

MTN_VIPER

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Nov 26, 2007
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NW WA St.
fourstrokesolutionsllc.com
I noticed is that my sled runs hotter when standing up vs sitting down. The difference is really noticeable when slow speed boondocking through the trees. I did some experimenting with overheating on my sled and I found that ride height in the rear skid makes a huge difference. When I'm sitting down the rear of the sled is squatted down more vs when standing.
Basically the closer the snow flap is to the snow, the cooler the sled runs. I suspect this is because it allows the snow flap to deflect the roost back on to the paddles more, which in turn carries the snow back up to the heat exchanger.

Normally I run 120 psi in the rear shock and when I dropped the pressure down to 110-115 psi there is a noticeable improvement in cooling. The draw back to being in the 110-115 psi range, is that there is more sag unloaded and ride quality/handling was somewhat reduced.

Taking it to next level I decided to try a Hygear dual pressure reservoir on the rear shock. Basically it makes the shock in to an EVOL type shock. Depending on where you set the pressures, a dual pressure shock is more linear. This allows you to be able run a slightly higher main chamber pressure and still utilize the full suspension travel without it becoming to stiff towards the end of the travel.

I set the main chamber pressure back up to 120 psi and 180 psi in the bottom out chamber. I have just one ride on it so far on firmer spring snow, but the sled rides better and more importantly the heat light never came on once all day! I'll probably have to wait until next season to know for sure if the shock mod helps with cooling, but so far the results look promising.
 

sno*jet

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Dec 13, 2007
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my buddy runs no flap without issue. I think some people were not meant for liquid cooled sleds. Its too bad there is not more of a fan cooled market anymore. they should bring the 570 back in the new chassis.
 
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