2001 Mountain Cat 800 Problems Please Help!

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moosesp

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Dec 6, 2007

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• Dec 10, 2007

• #1

Just thought i'd ask a few questions for my friend. He has a 2001 MC 800 Carb with ATTAC. I will tell you the simptoms and see if anyone has had the same problems. It seems to be elevation ralated but we don't know for sure. We were in the mountains last year and the sled was running fine on the trail up to the top. The elevation change was probably 4000-5000 feet from bottom to top. As soon as we got to the top the sled would not pull over 4500 rpm. Both cylinders were firing and we eliminated an ATTAC problem I think. It doesn't seem to be a fuel rich issue. The Exhaust valves also seem to be working correctly. Does the ignition system on this sled change the timing based on elevation? Does the temp sensor on the engine change the timing if the engine becomes too hot or if the sensor malfunctions? Just thought somone might have experience with this.

Thank you,

 

A

arcticcat38

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Nov 26, 2007

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• Dec 10, 2007

• #2

is it efi or carbed?

 

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CATillak

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Nov 26, 2007

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dankorage

• Dec 10, 2007

• #3

i dont beleive the 01 had EFI as an option?????

 

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CATillak

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dankorage

• Dec 10, 2007

• #4

sorry for 2nd reply, edit wouldnt load.


is the sled stock? maybe the weights are too heavy? just throwing that out there

 

colorado_matt

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COLORADO

• Dec 10, 2007

• #5

How many miles does the sled have on it? Has the primary clutch ever been serviced or rebuilt? I had an '01 MC 800 and put on a polaris p-85 clutch. The rollers and bushings should be checked a couple times a year if you ride much. If you wait too long, the clutch will become unbalanced and eventually break the bolt and fly off.

 

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diggerdown

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Apr 25, 2004

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Deer Park Wi.

• Dec 10, 2007

• #6

Did it work again when you got to a lower elevation? The barimetric pressure sensor on the ATTAC can go bad and not adjust. I would unhook the controller and try it with regular jetting. If it is bad a lower elevation too it is probably the ecu or maybe the wire conections from the trigger coil or the trigger coil itself.

 

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NEILBUY

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Dec 6, 2007

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• Dec 10, 2007

• #7

Have you ever successfully run the sled at that high altitude before? If yes, the problem could be alot of different things or a combination of several things. If you have never rode at that alititude before my money is also on the weights being to heavy. Look on top of the tool box under the hood there will be a chart that lists the correct weights for the altitude you ride. My 03 used 66 grams weights for 6000-9000. If you do check the clutch weights be sure to varify that all 3 weights are the same weight. I've come accross sleds that seem fine when tested at lower altitudes but the imbalance rears its ugly head at alititude. (Less horse power up there.)

 

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moosesp

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Dec 6, 2007

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• Dec 10, 2007

• #8

Thanks for the responses,

I was thinking more about the problem and its not totally elevation related. I think it is more of a deep snow relation. Is there any chance of the air intake on these sleds plugging off and restricting air flow to the engine. When this problem occurs the EGT's on both cylinders don't go over 450-475 degrees F. The sled also has twin D & D pipes and has been clutched for the 3000-6000 foot range. When the sled is running good the EGT's are proper at around 1000 degrees F full out. As for clutching this wouldn't have a 3000 rpm affect. He has never personally had the thing in the mountains before this. But the sled acted up once or twice back in the lower elevation as well.

 

WyoBoy1000

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Red Lodge MT to North, CO

• Dec 10, 2007

• #9

mine did similar things i got a new primary clutch and belt and it was like new

 

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diggerdown

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Deer Park Wi.

• Dec 11, 2007

• #10

With egt's in the 400's, what makes you think it was'nt rich? Even at 1000* it is still rich! And yes the air intakes do get clogged with powder, that makes them run rich. At 4500 you clutches would barley engage, how did you get out of the snow? I would guess the clutching needs work too, but I do think you have a air/fuel problem. Plug caps could be getting wet and misfiring also. With the holtzman comp. you should jet for the lowest elevation and temp that you will be running in and periodically pull the little blue hose off for a second at that elevation on a high pressure day. Resets the barimetric comp.

 

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JENSEN BROS

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Nov 27, 2007

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ELKHORN

• Dec 11, 2007

• #11

you have a couple of problems. one is d&d twin pipes. do not work at altitude very well. if you don't have the jetting and clutching perfect you lose out at any load on the engine like deep snow. they are notorious for having a small power band. if tuned correct, they rock. if you are off a little, you have less horsepower than the stock pipe. would recommend removing twins and installing a single. much more forgiving and easier to tune. to see if i am correct install the stock pipe and see if you severe bog comes back. i have been there and done that.