05' IQR with Polaris 685 engine setup

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IdahoPowderHound

Well-known member

Jul 3, 2008

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Alpine Wyoming

• Feb 1, 2010

• #1

Was just wondering If anyone could give me an idea on clutching and jetting for a 685 polaris with twins. Just bought the sled from a dealer and was told it was set up for 6 to 9 thousand feet. cant hold r's up at 8 to 9 thousand feet. Changed belt two weekends ago and im leaning twards cluching now. Was told that it had a low comp head on it for pump gas but im not sure that its safe to run a 685 with twin pipes on only pump fuel. Havnt tore into the clutches yet but did notice that the primary has a bright green spring. Any ideas would be greatly appriciated.

 

A

autolodge

Free Member

Nov 27, 2007

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43

Grand Marais, MN

• Feb 1, 2010

• #2

Take an LED light and look down you plug holes. How's the piston wash look? You should be able to see a thumb nail size part of bare aluminum on the top of your piston at each transfer port. Any more than that and you are running fat.

 

I

IdahoPowderHound

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Jul 3, 2008

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Alpine Wyoming

• Feb 2, 2010

• #3

anyone know of weight setup for the primary and spring that should be run with the 685 on pump fuel with twins at 7-10 thousand feet? What about gearing and secondary setup and belt size. thanks

 

I

IdahoPowderHound

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Jul 3, 2008

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Alpine Wyoming

• Feb 4, 2010

• #4

any ideas on the primary weight setup at 7-10 thousand feet for this engine setup with a 155 polaris track? Just having problems holding rpm's in deeper powder. thanks

 

I

IQmodster

New member

Jan 4, 2009

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8

In the cold

• Feb 5, 2010

• #5

RMPs

Are you hitting your peak RPM then it drops back or doesn't it even hit top RPM at all? (Top RPM depends on the recommendations of the pipe manufacture)

 

I

IdahoPowderHound

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Jul 3, 2008

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Alpine Wyoming

• Feb 5, 2010

• #6

Im only pulling 7,900 RPM's. Was just told that its a comon problem and that the fix is a different helix.

 

I

IQmodster

New member

Jan 4, 2009

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In the cold

• Feb 6, 2010

• #7

Okay. You can try that and let us know.

I would think it is your primary wts. being a little heavy or too much on the toes. Can you see it shifting(on your tach)?

There is a great thread on Snowest under performance/modifications describing the art or clutching check it out.