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High elevation hesitation

E
Dec 8, 2008
812
36
28
Chelan area
On my 670x, when i get into the higher elevations (say, 4-5000ft and up) the sled lacks power, it dosnt stumble or bog out, it just dosnt have that last 1/8" throttle response (the final BWAAAAAAAAAH!). I thought it could be my clutches, as i have never adjusted them until this year, i also thought it could be my DPM (Digital Performance Manegement). How would i go about pinpointing the problem? Can i "test" the DPM? Thanks guys. :cool:
 
D
Nov 11, 2009
8
0
1
Hi there.I had a friend who had similiar problems with a 99x only his would lose power but it ran fine below 4000 ft ,after much frustration we discovered pto side bearing was failing and had taken seals with it , piston damage was evident also . The clue that led us into the engine was the pto side carb slide/plunger was moderately scored on the engine side of it,basically telling us that something was being blown back onto it .Hope this helps.:)
 
4
Aug 27, 2009
43
2
8
Laramie, WY
What jets are you running I have a 98 X modded now but stock jets were 340PTO 330 MAG. The last 1/4 throttle should be your main jet it plays a part everywhere else but most significantly up top. Also what rpm are you limiting at and engaging at. I ride 9-11,000 mostly and anything below 4300 rpm for engagement and it was a dog in the trees on the stock setup. And it ran best with the primary limiting at 7900-8000 rpm. The easiest first step is to mess with the clickers there are three bolts on the perimeter of the primary. Loosen the nut but don't take it all the way off just far enough to turn the head of the bolt to another position. There is a hash mark on the bolt head that points to the "clicker number." The higher the number the higher the limiting rpm and engagement speed. Each number is about 200 higher governer rpms

To check the main jet (relative to altitude) with the sled warm, Pin the throttle for 300yards or so and hit the kill switch with your opposite hand. Pull the plugs and look at the electrode color, milk choclate is good and safe.

The DPM workes well on my sled, I know there is a way to check, i can't remember the profession way. Seems to me a basic check was to un plug the two plugs going into the rail and the air sensor on the air box. If the sled runs poorly and super rich with things unpluged compared to everything plugged in then the DPM works.

There was also a factory recall on a screw coming loose inside the DPM rail on the early 98's. The recall is long since over. My guess is if you didn't have this problem initially then you don't have to worry about it.
 
E
Dec 8, 2008
812
36
28
Chelan area
Hi there.I had a friend who had similiar problems with a 99x only his would lose power but it ran fine below 4000 ft ,after much frustration we discovered pto side bearing was failing and had taken seals with it , piston damage was evident also . The clue that led us into the engine was the pto side carb slide/plunger was moderately scored on the engine side of it,basically telling us that something was being blown back onto it .Hope this helps.:)

I DONT WANNA HERE IT! haha, thanks for the info dano.

What jets are you running I have a 98 X modded now but stock jets were 340PTO 330 MAG. The last 1/4 throttle should be your main jet it plays a part everywhere else but most significantly up top. Also what rpm are you limiting at and engaging at. I ride 9-11,000 mostly and anything below 4300 rpm for engagement and it was a dog in the trees on the stock setup. And it ran best with the primary limiting at 7900-8000 rpm. The easiest first step is to mess with the clickers there are three bolts on the perimeter of the primary. Loosen the nut but don't take it all the way off just far enough to turn the head of the bolt to another position. There is a hash mark on the bolt head that points to the "clicker number." The higher the number the higher the limiting rpm and engagement speed. Each number is about 200 higher governer rpms

To check the main jet (relative to altitude) with the sled warm, Pin the throttle for 300yards or so and hit the kill switch with your opposite hand. Pull the plugs and look at the electrode color, milk choclate is good and safe.

The DPM workes well on my sled, I know there is a way to check, i can't remember the profession way. Seems to me a basic check was to un plug the two plugs going into the rail and the air sensor on the air box. If the sled runs poorly and super rich with things unpluged compared to everything plugged in then the DPM works.

There was also a factory recall on a screw coming loose inside the DPM rail on the early 98's. The recall is long since over. My guess is if you didn't have this problem initially then you don't have to worry about it.

ALL last year i ran on clicker 3, i didnt know A THING about adjusting clutches or that i could, so i left it. As of now i have it set to clicker 4 and im gonna see how that works out. Dont know what jets im running, probly low alltitude being it runs amazing under 5k. I USUALLY ride around 2500-3500ft, and when i go mountain riding its 3000-9000ft. I dont know what rpm im running at, i really didnt know alot about my sled last year, as i enheareted it from my dad that same year. Im sure its somewhere around there though (same as you) i remember asking my dad- "are the RPM's sappose to be that high?!!". haha.

When i get out on my first ride i'll try the cut-off technique, i dont have a kill switch but i'll just pull the tether. Mines a 99 so im not sure if the loose screw deal applys to me. Thanks for the help! I'll unplug the DPM when the sled is warmed up in the middle of a ride and see how it runs, mabey start it, wait a second for the DPM to help the idle and un-plug it and see if it stumbles?
 
D
Nov 11, 2009
8
0
1
hesitating 670

sorry for scaring ya.i do hope you find the problem and its not expensive like my friends was.Maybe pull the carb slides and take a peak or for the sake of a couple of o-rings pull the head to make sure all is well under the dome,before you start replacing external stuff or pulling your hair out.lol:beer;
 
E
Dec 8, 2008
812
36
28
Chelan area
sorry for scaring ya.i do hope you find the problem and its not expensive like my friends was.Maybe pull the carb slides and take a peak or for the sake of a couple of o-rings pull the head to make sure all is well under the dome,before you start replacing external stuff or pulling your hair out.lol:beer;

I pulled the Y pipe off a couple weeks ago and i could kina see the piscons and rings, they looked ok.
 
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