My RMK Caught Fire

[Skeld]

Big problems this weekend. I'm not a mountain rider, I ride in the Maine backcountry. I was breaking out a road with about 4' of snow on it...I could only maintain about 30 MPH, 6500 to 7000 RPM (not full throttle though). Belt was doing fine, but I looked down after about 2 miles of being the first sled and I see orange flames through the right side panel vent!

Muffler got so hot it set the side panel foam on fire. I dropped the panel and started bailing snow in. It warped my hood and belly pan some, I had to bungee the side panel on. Also singed the recoil rope so badly that it promptly broke. What a pain in the ***...

After this I rode the sled about 50 more miles and it seems to run fine...any ideas why this happened? It's kind of a drawback for me if I have to let a 600 ETEC 146 Summit break trail for me.

Some facts: Sled has 3600 miles on it. Elevation about 1200 ft., sled is clutched for 0-2000 ft. All stock. This fall at 2550 miles it had 125/126 PSI compression. Water temperature was 132 at the time. Seems to run fine before and after, other than it will struggle to pull max RPM at higher speeds. It will pull max RPM at slow speeds, full throttle, deep snow.

 

[Robbie]

It sounds to me that your brake was stuck. Either the parking brake was on, or the brake pads didn't release. I'd look at your brake disk and see if it is blue.

 

[Skeld]

I've never even set the parking brake before. Interesting thought, but I don't think I could have overcome the brake plus the snow. Maybe they were stuck, but I normally am pretty paranoid about how much rolling resistance I'm feeling, and the disc isn't blue.

Also I ride with a finger on the brake all the time so I would have noticed something being off I think.

 

[maurfello]

You could have a hole in your exhaust. My Pro RMK had a hole in the pipe under the heat shield and melted my plastics in a similar way but I caught it before it caught on fire. If you notice lots of loose fibers under the hood that may be the issue.

PRO RMK 800

 

[Skeld]

You could have a hole in your exhaust. My Pro RMK had a hole in the pipe under the heat shield and melted my plastics in a similar way but I caught it before it caught on fire. If you notice lots of loose fibers under the hood that may be the issue.

PRO RMK 800

Haven't noticed anything but definitely worth taking a closer look, thanks.

 

[BigMan]

Now the whole Dragon thing kind of makes sense?

 

[die hard poo]

Could be a fuel injector failing dumping extra unburnt fuel into your exhaust causing a fire... At least that is how I have seen other pros catch fire. But most of them weren't so fortunate to be able to extinguish the fire.

 

[Powderforlife907]

One of the Iron Dog guys 600 Rush caught fire. Looks like way too much fuel...

http://youtu.be/3bebj6CcP-E

 

[roni87]

flames

My 12assault had flames out the exhaust earlier this year too. Would happen after a short 10
second wot pull.
Here's what I did:
1 pint of toulene solvent in gas
Slp sparkplug wires
New plugs gapped .018

Stock plug caps seem to have arcing issues imo.

 

[ditch1000]

A guy I know had the same thing happen to his 13 PRO RMK 600, the sled had only 400 miles. Polaris checked the sled over twice and it did not have any codes... His thinking is the insulating foam fell off the side panel and melted on the muffler and caused the fire... Food for thought....

 

[Skeld]

A guy I know had the same thing happen to his 13 PRO RMK 600, the sled had only 400 miles. Polaris checked the sled over twice and it did not have any codes... His thinking is the insulating foam fell off the side panel and melted on the muffler and caused the fire... Food for thought....

Could be as simple as that foam being too close.

I saw the Iron Dog video before, apparently the exhaust fire caught the vapors from fueling on fire...not good. I doubt I had open flames coming out the exhaust so not sure why my panel caught on fire and the ID guy's did not.

 

[diamonddave]

Could be as simple as that foam being too close.

I saw the Iron Dog video before, apparently the exhaust fire caught the vapors from fueling on fire...not good. I doubt I had open flames coming out the exhaust so not sure why my panel caught on fire and the ID guy's did not.

Maybe...

But if it were me, I would still have the injectors flow tested and cleaned just to verify there isn't a possible repeat.

Fire sucks when not wanted.

 

[Woodsrider]

Iron Dog fire happened after fuel was sprayed on outside of fuel tank. Sled was running (as required) and had flame coming out of exhaust. Run into McGrath fuel stop was done at extended high speed. FYI 2 years ago it was a Ski Doo that flamed on.
http://www.ktuu.com/news/news/watch-iron-dog-sled-bursts-into-flames/24548190

 

[Skeld]

Maybe...

But if it were me, I would still have the injectors flow tested and cleaned just to verify there isn't a possible repeat.

Fire sucks when not wanted.

I agree. Kind of ruined my day. I'll have the dealer look in that direction. Probably going to be about $1k in parts to fix the cosmetic damage.

I think I'm going to skip the foam kit on the new panel, that might help.

 

[Powderforlife907]

Iron Dog fire happened after fuel was sprayed on outside of fuel tank. Sled was running (as required) and had flame coming out of exhaust. Run into McGrath fuel stop was done at extended high speed. FYI 2 years ago it was a Ski Doo that flamed on.
http://www.ktuu.com/news/news/watch-iron-dog-sled-bursts-into-flames/24548190

I was just pointing out the constant flame coming out of exhaust. I have never seen a stroke motor do it that much before..... It has too be over fueling to do that.

 

[Woodsrider]

Over fueling could possibly be the cause of flame out of the exhausted. Most Polaris teams run there sleds in the ethanol mode to compensate for regular fuel. Couple that with the nature of 2 stoke motors to allow unburned fuel to escape the cylinder and collect in the muffler. At idle enough oxygen could enter muffler outlet to ignite this unburned fuel. The run into McGrath is fairly long and at high speed and this year very little to no snow for cooling so motors and exhaust were very hot.

 

[Jaynelson]

I would check the brake...with that much snow, it can get trapped (or refreeze) in the lever itself and hold it on juuuust enough to drag. Has happened to me and a few sleds in certain snow conditions.

 

[pulltype_polaris]

Id say your tps is set on the edge of the lean side. My 600 sb with stock muffler got so hot the hood started dripping plastis on it and it deformed the side panel. Dealer checked it out couple time and never found out the issue. That was my only guess as to why it would get too hot. According to the plugs they were always a bit on the light side

 

[Skeld]

It's a little puzzling really. You'd think I would have smoked the motor if I was running lean enough to set the side panel on fire through the muffler...but they checked the motor and it's still 125/125 psi. Also I was probably getting 8 MPG or less that day and I was into it for half throttle or slightly more to maintain 25-30 MPH ground speed. Keep in mind also I'm only at 1,000 feet here so I have more power than you guys might out west.

The new panel isn't going to have the foam on it. I'm hoping that will leave a little more room for circulation...also, I think in powdery snow there is enough spray to cool things down but in wet heavy snow it doesn't get to the panel at all.

 

[sledneck322]

Those mufflers get super hot....at least according to my food coming out of my muff pot for lunch...lol. Seriously though, they do get hot and maybe the panel was a little closer than normal for whatever reason (rolling over after getting stuck...etc) and it was just hot enough to ignite. I would put adhesive backed heat tape on the inside of your panel and do not reinstall the sound deadening foam.

I have seen the pipe melt side panels on summits before but not catch fire.