Ok here's the situation. I have been having issues with getting my 09 D8 to pull rpm. I have been pulling around 7700. I have put on a new fuel filter, new clutch springs, gone through the clutches, added a power addiction head, checked motor mounts. Im running slp pipe and intake and now the head. Im running 68g mtx weights with an 1oz in each hole, slp blue pink, stock secondary spirng and helix. Just cleaned power valves and changed to pink spring, bilows looked good, plugged of cylinoid. I tend to run around 7-9000ft. I'm running out of ideas. Is it possible for tps to get out of adjustment. Only thing i can think of now. Sled was updated in january of last year so it has what ever flash was current then.
Need help low r's
- Thread starter modjunkie
- Start date
Sounds a lot like my problem. Let me know if you figure it out.
Did yours ever run the right r's with the current set-up?
http://www.snowestonline.com/forum/showthread.php?t=255352
Did yours ever run the right r's with the current set-up?
http://www.snowestonline.com/forum/showthread.php?t=255352
Seen the exact same problem a few times now, its getting quite common..and as of yet no one has found a sure fix for it....sucks just hits a wall at aroud 7700-8000 no matter what you do. One sled even runs the same rpm with 58,s as it does with 64's in back to back tests...just crazy
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mtnclmr
Member
I know you guys have checked your exhaust valves already, but thats pretty much how the sleds I've seen with valve issues have ran. You could try pulling the springs out and running it, also check those little holes under the bellow where it gets its pressure from the engine, make sure they are not plugged up. Another thought was your exhaust partially plugged, packing coming loose in the can? Just some ideas.
When i first got the sled it ran, around 81-8200. Then one day it just quit pulling. Have not changed the set up. The only thing that changed was the update, thats why i thought the head might fix the problem. Sled diffently pulls harder on the top end with head but still wont rev. It wouldn't be so bad, but the two m8's i ride with kill me on the hill.
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deepdiver
Well-known member
After the Jan 2010 update, compression is lower. Light riders dont notice much difference but heavier riders do.
You didnt mention if this was a turbo sled but 68's are heavy for your elevation for a stock motor. I would run 10/62's...the SLP lite blue with pink spring doesnt impress me..I ran it for a bit and pulled it out and went back to a new stock primary spring.
I weigh 245 and ran into a simular problem..I would hit 7900 like a brick wall. I played with weights and they wouldnt get it to where it needed to be no matter what I did..I went heavier on the reccomendation of a Polaris mech..and she fell flat on her face. 10/62's at 6-8K work.
I changed secondary helix to a SLP 58/38-58/40 er .46
Use a Team red/black spring left hand secondary. switched to Team 10/62's in the Primary and of course the little infamous delrin washer for secondary spring.
After that I hit 8150 dead on!
You didnt mention if this was a turbo sled but 68's are heavy for your elevation for a stock motor. I would run 10/62's...the SLP lite blue with pink spring doesnt impress me..I ran it for a bit and pulled it out and went back to a new stock primary spring.
I weigh 245 and ran into a simular problem..I would hit 7900 like a brick wall. I played with weights and they wouldnt get it to where it needed to be no matter what I did..I went heavier on the reccomendation of a Polaris mech..and she fell flat on her face. 10/62's at 6-8K work.
I changed secondary helix to a SLP 58/38-58/40 er .46
Use a Team red/black spring left hand secondary. switched to Team 10/62's in the Primary and of course the little infamous delrin washer for secondary spring.
After that I hit 8150 dead on!
Sled is not a turbo. Two weeks ago i ran 10/60's and still could not pull over 7800. Went back to the mtxs and pulled weight out of the tips didn't change a thing. Thinking about checking fuel pressure maybe the pumps getting weak, but it doesn't seem to get weaker as i pull just goes there and stays as long as you hold it wide open.
I also have been having problems with rpm's can barely hit 78, used to pull 82 to 83 day in and day out. I also pulled some weight out of the mtx weights didnt help at all. Yesterday I opened it up on a trail it hit 78 and slowly fell to 72 to 73.
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SpokaneRMK
Well-known member
I had the same exact problem, Bough a pcv and i am now able to hold 8100, i think the top end in the stock mapping is way to rich and the sled just falls on its face, i've been through all sorts of clutching changes, still not getting the r's that i want(8300), but adding the pcv definitely helped the top end.
That might help but still doesnt explain why it ran spot on earlier but now is falling on its face.
Talked with a very reliable source today. He said he gets this question a bunch wishes he could just set up a recording to answer it. Basically what he told me is that they have found that it is bottom ring failure. It wont show up in a compression test because the top ring holds it until you are really pulling hard. This is just one of the many pieces to the problem. He also said that the tolerances of the stock polaris pistons allows for virtually no wear. He pretty much told that in 400 miles after my update that the pistons are shot and the motor just wont hold compression under heavy load. He said to plug the decompression holes that that would help as well. He also said that a pcv is a must to make these sleds reliable. Once the bottom ring goes it rocks the piston just a little and causes the scuffing that we all see. I told him that i was seeing a little scuffing and he told me that he could gaurntee that me top end was shot. He said that these sleds just run way to hot and cause excessive wear. He also said that alot of the oils we run just don't protect these newer style motors like they should, and recommended that i run redline from all of there testing it was the best oil to protect against the excessive heat these motors porduce.It was really depressing to find out but everything he said makes perfect sense to my issuse.
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SpokaneRMK
Well-known member
K, today had a vr replaced, idle set, and tps set, sled was rode today, sled still won't run right, hits 8k and holds for seconds, then spits and drops some r's, i'm FRUSTRATED. Sled will b home tomorrow, gonna check fuel filter, and pull powervalves and take a look.
whoever you heard this from is dead on based on my 09 800 engine failures (in my opinion). so i think basically the next time i loose rpms, if i still own this wreck i must replace the top end.
When you have your power valves out shine a light down the hole and check your pistons for scuffing. Just curious what you'll see. How many miles on your top end?
try changing your belt mine would only pull 7800 changed my belt and im back up to 8200.
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SpokaneRMK
Well-known member
500 miles on top end........will b looking at top end tomorrow night
Spark plugs do that sometimes under load when they're starting to fail.
New top end didn't fix my rpm's although the pistons clearance was way over spec.
my sled didnt pull rpm this year like it used to. long story short the spark plug caps were corroded. new caps and i was good to go.
After doing more investigating i ordered "the fix" from pms yesterday. Talked to the guys at hi mark rentals in west and they have not had a failure since they have started putting these kits on. I will be tearing down my topend in the next couple of days. I'm thourghly dissapointed that I can only get 400 miles out of a stock top end. My old 99 700 has about 3,000 hard miles with a head and pipe and still runs like a top, rest of the sled is pounded out, but the motor is still strong. Can't figure out how polaris can go from something so reliable to such a piece of junk. I was mad at my artic cat becuase no matter what i did i couldn't keep it from eating belts every 300 miles. I guess i can either change belts or top ends. Hopefully with the fix i wont have to do either. Shawn said they had sleds with 2000 miles on them still running the same top end. Will keep everybody posted on how it runs.
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SpokaneRMK
Well-known member
Well, tore it down last night, broken ring on exhaust side, need a new head, two pistons, cylinders redone, i'm pissed, cylinders measured at 84.99 thou, and pistons, 84.44 thou, now that it way to much slop, 500 miles, thank u polaris, u r the way out.
